Melatonin Ameliorates Busulfan-Induced Spermatogonial Stem Cell Oxidative Apoptosis in Mouse Testes

Ameliorating effects of selenium nanoparticle coated by gallic acid on histological and biochemical parameters of testis in azoospermic rat model

This study was designed to examine the effects of selenium nanoparticles (SeNPs) coated with gallic acid (GA) on testis in azoospermic rats. Thirty-six adult Wistar rats were assigned to six groups: control (1 ml intraperitoneal (i.p.) phosphate-buffered saline (PBS) for 7 consecutive days), SHAM (single i.p. injection of 1 ml of 8 % dimethyl sulfoxide (DMSO)), BUS (single i.p. injection of busulfan (BUS) 30 mg/kg body weight), GA (single i.p. injection of BUS 30 mg/kg on day 1, 100 mg/kg body weight GA from days 2-7), SeNPs (single i.p. injection of BUS 30 mg/kg on day 1, 0.5 mg/kg body weight SeNPs from days 2-7), and SeNPs-GA (single i.p. injection of BUS 30 mg/kg on day 1, 0.5 mg/kg body weight SeNPs-GA from days 2-7). Subsequently, serum levels of testosterone and insulin-like growth factor-1 (IGF-1), antioxidant markers, sperm parameters, and histological parameters were evaluated. The results showed that BUS injection induced azoospermia in rats by causing oxidative stress and testicular tissue damage. In contrast, co-administration of SeNPs and GA showed significant improvements in testosterone and IGF-1 levels, antioxidant status, testicular tissue characteristics, and sperm parameters. Overall, the findings suggest that GA-coated SeNPs offer therapeutic potential in BUS-induced azoospermic models.

A comparison of the potential of melatonin and tryptophan to ameliorate CCl4-induced hepatic and renal toxicity in Wistar rats

CCl4 causes oxidative injury, fatty degeneration, fibrosis of the liver, renal failure, and even hepatocellular and renal carcinoma. Certain substances have the potential to neutralize the harmful effects of CCl4, so it will lead to numerous beneficial effects. Melatonin (MEL) is a powerful antioxidant that regulates circadian rhythm and has beneficial effects on organism; tryptophan (TRP) is its precursor necessary for the synthesis of MEL. The aim of the current study was to determine whether MEL and TRP, have protective effects during subchronic application of CCl4 to the liver and kidneys. Results suggest that CCl4 led to decrease of total proteins, albumins, globulins, erythrocytes, hemoglobin, and hematocrit; and increase of creatinine, AST, ALT values, and leukocytes. MEL and TRP both showing protective effects on regulation of serum proteins, albumins, globulins, A/G, AST, ALT, and creatinine levels. TRP had been shown to have potential in regulation of disbalanced hematological parameters caused by CCl4. TRP had beneficial effects on hepatocyte morphology in term of beaded chromatin and preserved cell morphology. Overall, oral supplementation of TRP had better protective effects on liver/kidneys compared to MEL.

The effect of biological mechanisms of melatonin on the proliferation of spermatogonial stem cells: a systematic review

In the last decade, melatonin has gained recognition as a potent scavenger and an effective antioxidant capable of neutralizing free radicals, including reactive oxygen species. Additionally, it exhibits anti-apoptotic properties. In this review, we will examine a compilation of articles that explore the cellular signaling function of melatonin on spermatogonial stem cells (SSCs) and adjacent cells such as Sertoli and Leydig cells. These cells play a crucial role in the proliferation of SSCs both in vitro and in vivo. In this review, we analyze the function of melatonin in the proliferation of SSCs from other aspects. For this purpose, we examine the articles based on the presence of melatonin on SSCs in four groups: As a supplement in SSCs medium culture, SSCs three-dimensional culture system, SSCs freezing medium, and as a therapeutic factor in vivo. Mechanisms of growth and proliferation of SSCs were considered. The purpose of this study is to investigate the potential effects of melatonin as a powerful antioxidant or growth stimulant for SSCs, both in vivo and in vitro.

Arginine Biosynthesis Mediates Wulingzhi Extract Resistance to Busulfan-Induced Male Reproductive Toxicity

Busulfan, an indispensable medicine in cancer treatment, can cause serious reproductive system damage to males as a side effect of its otherwise excellent therapeutic results. Its widespread use has also caused its accumulation in the environment and subsequent ecotoxicology effects. As a Chinese medicine, Wulingzhi (WLZ) has the effects of promoting blood circulation and improving female reproductive function. However, the potential effects of WLZ in male reproduction and in counteracting busulfan-induced testis damage, as well as its probable mechanisms, are still ambiguous. In this study, busulfan was introduced in a mouse model to evaluate its production of the testicular damage. The components of different WLZ extracts were compared using an untargeted metabolome to select extracts with greater efficacy, which were further confirmed in vivo. Here, we demonstrate abnormal spermatogenesis and low sperm quality in busulfan-injured testes. The WLZ extracts showed a strong potential to rehabilitate the male reproductive system; this effect was more prominent in room-temperature extracts. Additionally, both water and ethanol WLZ extracts at room temperature alleviated various busulfan-induced adverse effects. In particular, WLZ recovered spermatogenesis, re-activated arginine biosynthesis, and alleviated the increased oxidative stress and inflammation in the testis, ultimately reversing the busulfan-induced testicular injury. Collectively, these results suggest a promising approach to protecting the male reproductive system from busulfan-induced adverse side effects, as well as those of other similar anti-cancer drugs.

Melatonin alleviates oxidative stress damage in mouse testes induced by bisphenol A

We investigated the effect of melatonin on bisphenol A (BPA)-induced oxidative stress damage in testicular tissue and Leydig cells. Mice were gavaged with 50 mg/kg BPA for 30 days, and concurrently, were injected with melatonin (10 mg/kg and 20 mg/kg). Leydig cells were treated with 10 μmol/L of BPA and melatonin. The morphology and organ index of the testis and epididymis were observed and calculated. The sperm viability and density were determined. The expressions of melatonin receptor 1A and luteinizing hormone receptor, and the levels of malonaldehyde, antioxidant enzymes, glutathione, steroid hormone synthases, aromatase, luteinizing hormone, testosterone, and estradiol were measured. TUNEL assay was utilized to detect testicular cell apoptosis. The administration of melatonin at 20 mg/kg significantly improved the testicular index and epididymis index in mice treated with BPA. Additionally, melatonin promoted the development of seminiferous tubules in the testes. Furthermore, the treatment with 20 mg/kg melatonin significantly increased sperm viability and sperm density in mice, while also promoting the expressions of melatonin receptor 1A and luteinizing hormone receptor in Leydig cells of BPA-treated mice. Significantly, melatonin reduced the level of malonaldehyde in testicular tissue and increased the expression of antioxidant enzymes (superoxide dismutase 1, superoxide dismutase 2, and catalase) as well as the content of glutathione. Moreover, melatonin also reduced the number of apoptotic Leydig cells and spermatogonia, aromatase expression, and estradiol level, while increasing the expression of steroid hormone synthases (steroidogenic acute regulatory protein, cytochrome P450 family 17a1, cytochrome P450 17α-hydroxylase/20-lyase, and, 17β-hydroxysteroid dehydrogenase) and the level of testosterone. Melatonin exhibited significant potential in alleviating testicular oxidative stress damage caused by BPA. These beneficial effects may be attributed to melatonin's ability to enhance the antioxidant capacity of testicular tissue, promote testosterone synthesis, and reduce testicular cell apoptosis.

Protection against cancer therapy-induced cardiovascular injury by planed-derived polyphenols and nanomaterials

Cancer therapy-induced heart injury is a significant concern for cancer patients undergoing chemotherapy, radiotherapy, immunotherapy, and also targeted molecular therapy. The use of these treatments can lead to oxidative stress and cardiomyocyte damage in the heart, which can result in heart failure and other cardiac complications. Experimental studies have revealed that chemotherapy drugs such as doxorubicin and cyclophosphamide can cause severe side effects such as cardiac fibrosis, electrophysiological remodeling, chronic oxidative stress and inflammation, etc., which may increase risk of cardiac disorders and attacks for patients that underwent chemotherapy. Similar consequences may also be observed for patients that undergo radiotherapy for left breast or lung malignancies. Polyphenols, a group of natural compounds with antioxidant and anti-inflammatory properties, have shown the potential in protecting against cancer therapy-induced heart injury. These compounds have been found to reduce oxidative stress, necrosis and apoptosis in the heart, thereby preserving cardiac function. In recent years, nanoparticles loaded with polyphenols have also provided for the delivery of these compounds and increasing their efficacy in different organs. These nanoparticles can improve the bioavailability and efficacy of polyphenols while minimizing their toxicity. This review article summarizes the current understanding of the protective effects of polyphenols and nanoparticles loaded with polyphenols against cancer therapy-induced heart injury. The article discusses the mechanisms by which polyphenols protect the heart, including antioxidant and anti-inflammation abilities. The article also highlights the potential benefits of using nanoparticles for the delivery of polyphenols.

Sitagliptin ameliorates busulfan-induced pulmonary and testicular injury in rats through antioxidant, anti-inflammatory, antifibrotic, and antiapoptotic effects

Busulfan (BUS) is an anticancer agent with serious adverse effects on various body organs, including the lung and testis. Sitagliptin was proven to have antioxidant, anti-inflammatory, antifibrotic, and antiapoptotic effects. This study aims to evaluate whether sitagliptin, a DPP4I, ameliorates BUS-induced pulmonary and testicular injury in rats. Male Wistar rats were split into control, sitagliptin (10 mg/kg), BUS (30 mg/kg), and sitagliptin + BUS groups. Weight change, lung and testis indices, serum testosterone, sperm parameters, markers of oxidative stress [malondialdehyde (MDA) and reduced glutathione (GSH)], inflammation [tumor necrosis factor-alpha (TNF-α)], and relative expression of sirtuin1 (SIRT1) and forkhead box protein type O1 (FOXO1) genes were estimated. Histopathological examination of lung and testicular tissues was done to detect architectural changes [Hematoxylin & Eosin (H&E)], fibrosis (Masson's trichrome), and apoptosis (caspase-3). Sitagliptin treatment reduced body weight loss, lung index, lung and testis MDA, serum TNF-α and sperm abnormal morphology, and increased testis index, lung and testis GSH, serum testosterone, sperm count, viability and motility. SIRT1/FOXO1 balance was restored. Also, sitagliptin attenuated fibrosis and apoptosis in lung and testicular tissues via reducing collagen deposition and caspase-3 expression. Accordingly, sitagliptin ameliorated BUS-induced pulmonary and testicular damage in rats via attenuating oxidative stress, inflammation, fibrosis, and apoptosis.

LncRNA5251 inhibits spermatogenesis via modification of cell-cell junctions

BACKGROUND

Male factors-caused decline in total fertility has raised significant concern worldwide. LncRNAs have been identified to play various roles in biological systems, including spermatogenesis. This study aimed to explore the role of lncRNA5251 in mouse spermatogenesis.

METHODS

The expression of lncRNA5251 was modulated in mouse testes in vivo or spermatogonial stem cells (C18-4 cells) in vitro by shRNA.

RESULTS

The sperm motility in two generations mice after modulation of lncRNA5251 (muF0 and muF1) was decreased significantly after overexpression of lncRNA5251. GO enrichment analysis found that knockdown lncRNA5251 increased the expression of genes related to cell junctions, and genes important for spermatogenesis in mouse testes. Meanwhile, overexpressing lncRNA5251 decreased the gene and/or protein expression of important genes for spermatogenesis and immune pathways in mouse testes. In vitro, knockdown lncRNA5251 increased the expression of genes for cell junction, and the protein levels of some cell junction proteins such as CX37, OCLN, JAM1, VCAM1 and CADM2 in C18-4 cells. LncRNA5251 is involved in spermatogenesis by modulation of cell junctions.

CONCLUSION

This will provide a theoretical basis for improving male reproductive ability via lncRNA.

Melatonin Ameliorates Diquat-Induced Testicular Toxicity via Reducing Oxidative Stress, Inhibiting Apoptosis, and Maintaining the Integrity of Blood-Testis Barrier in Mice

Diquat is a fast, potent, and widely used bipyridine herbicide in agriculture and it induces oxidative stress in several animal models. However, its genotoxic effects on the male reproductive system remain unclear. Melatonin is an effective free-radical scavenger, which has antioxidant and anti-apoptotic properties and can protect the testes against oxidative damage. This study aimed to investigate the therapeutic effects of melatonin on diquat-induced testicular injury in mice. The results showed melatonin treatment alleviated diquat-induced testicular injury, including inhibited spermatogenesis, increased sperm malformations, declined testosterone level and decreased fertility. Specifically, melatonin therapy countered diquat-induced oxidative stress by increasing production of the antioxidant enzymes GPX1 and SOD1. Melatonin treatment also attenuated diquat-induced spermatogonia apoptosis in vivo and in vitro by modulating the expression of apoptosis-related proteins, including P53, Cleaved-Caspase3, and Bax/Bcl2. Moreover, melatonin restored the blood-testicular barrier by promoting the expression of Sertoli cell junction proteins and maintaining the ordered distribution of ZO-1. These findings indicate that melatonin protects the testes against diquat-induced damage by reducing oxidative stress, inhibiting apoptosis, and maintaining the integrity of the blood-testis barrier in mice. This study provides a theoretical basis for further research to protect male reproductive health from agricultural pesticides.

The role of cur ole of curcumin against paclitax cumin against paclitaxel-induced o el-induced oxidativ xidative stress and DNA damage in testes of adult male rats

BACKGROUND

Paclitaxel is a widely used drug for the treatment of cancer, but it possesses toxic effects on male reproductive system. Administering paclitaxel with an antioxidant has become a strategy for preventing the side effects of paclitaxel. Although curcumin is an antioxidant, data concerning the effect of curcumin on paclitaxel-induced testis tissue are lacking. The present study was established to examine the protective impact of curcumin against testicular damage induced by paclitaxel.

METHODS

In the study, 40 Wistar albino male rats were used and randomly divided into 4 groups (n:10). The control group received only saline solution; the curcumin group received curcumin throughout the experiment; the paclitaxel group received a total of four doses of paclitaxel on days 1, 7, 14, and 21 of the experiment; curcumin + paclitaxel group received curcumin throughout the experiment and a total of four doses of paclitaxel on days 1, 7, 14, and 21 of the experiment. At the end of the experiment, the rats were decapitated under xylazine and ketamine anesthesia and their testicles were removed. The sections obtained from the testicles were stained with Hematoxylin & Eosin and histopathological damage was evaluated. The TUNEL method was applied to determine apoptotic cells. Testosterone levels were measured in the blood serum. The Johnsen testicular biopsy score (JTBS) was used to evaluate testicular tubules. DNA damage was evaluated in sperm samples taken from the ductus epididymis using the comet assay technique.

RESULTS

Testicular tissue was severely damaged in the paclitaxel group. In the curcumin + paclitaxel group, it was determined that the administration of curcumin with paclitaxel reduced the histological damage in the testicular tissue. Moreover, according to the JTBS, the value was significantly higher in the testicular tubules (p < 0.05). Testosterone levels were higher in curcumin + paclitaxel group than in paclitaxel group. DNA damage also decreased significantly in curcumin + paclitaxel group when compared to paclitaxel group (p < 0.05).

DISCUSSION

The results showed that curcumin may be protective against damage caused by paclitaxel in the testicles of rats.

Overview of biological effects of melatonin on testis: A review

Infertility is a major global health issue and male factors account for half of all infertility cases. One of the causes of male infertility is the loss of spermatogonial stem cells, which may occur because of chemotherapy, radiotherapy or genetic defects. In numerous animal species, the evidence suggests the pineal gland and melatonin secretion in their reproductive activities are involved. Recently, considerable attention has pointed to the usage of melatonin in the treatment of diseases. Melatonin is associated with the regulation of circadian and seasonal rhythmic functions, immune system functions, retinal physiology, spermatogenesis and inhibition of tumour growth in different species. Several studies demonstrated that melatonin acts as an anti-apoptotic, anti-inflammatory, anticancer and antioxidant agent. Melatonin can also protect testicles and spermatogonia against oxidative damage, chemotherapy drugs, environmental radiation, toxic substances, hyperthermia, ischemia/reperfusion, diabetes-induced testicular damage, metal-induced testicular toxicity, improve sperm quality and it affects the testosterone secretion pathway by affecting Leydig cells. Therefore, the objective of this study is to investigate the biological effects of melatonin as a natural antioxidant on testicles and their disorders.

The antagonistic effect of melatonin on TBBPA-induced apoptosis and necroptosis via PTEN/PI3K/AKT signaling pathway in swine testis cells

Tetrabromobisphenol A (TBBPA) is a widely used industrial brominated flame retardant, which can endanger animal and human health, including cytotoxicity, endocrine disruption, reproductive toxicity and so on. Melatonin (MT) is a noteworthy free radical scavenger and an antioxidant to alleviate oxidative stress. To investigate the cytotoxic of TBBPA on swine testis cells (ST cells), as well as the antagonistic effect of MT, we established TBBPA exposure and MT antagonistic models, used flow cytometry and AO/EB staining methods to detect apoptosis and necroptosis, used DCFH-DA method to examine the content of reactive oxygen species (ROS) and investigated the expression of associated genes using RT-PCR and Western blot. According to our findings, TBBPA exposure induced cell death in ST cells. TBBPA increased ROS levels, thus increasing PTEN expression and decreasing PI3K and AKT expression. Apoptosis-related factors (Caspase-3, Bax, Cyt-c, and Caspase-9) and necroptosis-related factors (RIPK1, RIPK3, and MLKL) were considerably elevated, in addition to the reduced expression of BCL-2 and Caspase-8. We also found that MT inhibited apoptosis and necroptosis in TBBPA-induced ST cells and effectively resolved the abnormal expression of related signaling pathways. In summary, the above results indicate that MT alleviates the disorder of PTEN/PI3K/AKT signaling pathway via inhibiting ROS overproduction, thereby mitigating apoptosis and necroptosis caused by TBBPA. This research provides a theoretical basis for further understanding of the toxicity of TBBPA and the detoxification of MT against environmental toxics.

Antioxidant Effect of Melatonin on Proliferation, Apoptosis, and Oxidative Stress Variables in Frozen-Thawed Neonatal Mice Spermatogonial Stem Cells

Cryopreservation of spermatogonial stem cells (SSCs) is an important method to restore and maintain fertility in preadolescent children suffering from cancer. For protection of SSCs from cryoinjury, various antioxidant agents have been used. The aim of this study was to assess the antiapoptotic and antioxidant effects of melatonin in frozen-thawed SSCs. SSCs were isolated from testes of neonatal mice (3-6 days old) and their purities were measured by flow cytometry with promyelocytic leukemia zinc finger protein. After culturing, the cells were frozen in two groups (1) control and (2) melatonin (100 μM) and stored for 1 month. Finally, the cell viability, colonization rate, expression of Bcl-2 and BAX gene, and intracellular reactive oxygen species (ROS) were evaluated after freezing-thawing. Melatonin increased the viability and colonization of SSCs and Bcl-2 gene expression. It also diminished BAX gene expression and intracellular ROS. The results of this study show that melatonin with antioxidant and antiapoptotic effects can be used as an additive for freezing and long-term storage of cells and infertility treatment in the clinic.

Melatonin in cryopreservation media improves transplantation efficiency of frozen-thawed spermatogonial stem cells into testes of azoospermic mice

Background

Cryostorage of spermatogonial stem cells (SSCs) is an appropriate procedure for long-term storage of SSCs for fertility preservation. However, it causes damage to cellular structures through overproduction of ROS and oxidative stress. In this study, we examined the protective effect of melatonin as a potent antioxidant in the basic freezing medium to establish an optimal cryopreservation method for SSCs.

Methods

SSCs were obtained from the testes of neonatal male mice aged 3–6 days. Then, 100 μM melatonin was added to the basic freezing medium containing DMSO for cryopreservation of SSCs. Viability, apoptosis-related markers (BAX and BCL2), and intracellular ROS generation level were measured in frozen–thawed SSCs before transplantation using the MTT assay, immunocytochemistry, and flow cytometry, respectively. In addition, Western blotting and immunofluorescence were used to evaluate the expression of proliferation (PLZF and GFRα1) and differentiation (Stra8 and SCP3) proteins in frozen–thawed SSCs after transplantation into recipient testes.

Results

The data showed that adding melatonin to the cryopreservation medium markedly increased the viability and reduced intracellular ROS generation and apoptosis (by decreasing BAX and increasing BCL2) in the frozen–thawed SSCs (p < 0.05). The expression levels of proliferation (PLZF and GFRα1) and differentiation (Stra8 and SCP3) proteins and resumption of spermatogenesis from frozen–thawed SSCs followed the same pattern after transplantation.

Conclusions

The results of this study revealed that adding melatonin as an antioxidant to the cryopreservation medium containing DMSO could be a promising strategy for cryopreservation of SSCs to maintain fertility in prepubertal male children who suffer from cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03029-1.

Identification of a Crosstalk among TGR5, GLIS2, and TP53 Signaling Pathways in the Control of Undifferentiated Germ Cell Homeostasis and Chemoresistance

Spermatogonial stem cells regenerate and maintain spermatogenesis throughout life, making testis a good model for studying stem cell biology. The effects of chemotherapy on fertility have been well-documented previously. This study investigates how busulfan, an alkylating agent that is often used for chemotherapeutic purposes, affects male fertility. Specifically, the role of the TGR5 pathway is investigated on spermatogonia homeostasis using in vivo, in vitro, and pharmacological methods. In vivo studies are performed using wild-type and Tgr5-deficient mouse models. The results clearly show that Tgr5 deficiency can facilitate restoration of the spermatogonia homeostasis and allow faster resurgence of germ cell lineage after exposure to busulfan. TGR5 modulates the expression of key genes of undifferentiated spermatogonia such as Gfra1 and Fgfr2. At the molecular level, the present data highlight molecular mechanisms underlying the interactions among the TGR5, GLIS2, and TP53 pathways in spermatogonia associated with germ cell apoptosis following busulfan exposure. This study makes a significant contribution to the literature because it shows that TGR5 plays key role on undifferentiated germ cell homeostasis and that modulating the TGR5 signaling pathway could be used as a potential therapeutic tool for fertility disorders.

Activation of MT1/MT2 to Protect Testes and Leydig Cells against Cisplatin-Induced Oxidative Stress through the SIRT1/Nrf2 Signaling Pathway

There is growing concern that chemotherapy drugs can damage Leydig cells and inhibit the production of testosterone. Increasing evidence shows that melatonin benefits the reproductive process. This study mainly explores the protective effect and possible molecular mechanism of melatonin regarding cisplatin-induced oxidative stress in testicular tissue and Leydig cells. We found that there were only Leydig and Sertoli cells in the testes of gastrointestinal tumor patients with azoospermia caused by platinum chemotherapeutic drugs. Melatonin (Mel) receptor 1/melatonin receptor 2 (MT1/MT2) was mainly expressed in human and mouse Leydig cells of the testes. We also observed that the melatonin level in the peripheral blood decreased and oxidative stress occurred in mice treated with cisplatin or gastrointestinal tumor patients treated with platinum-based chemotherapeutic drugs. iTRAQ proteomics showed that SIRT1/Nrf2 signaling and MT1 proteins were downregulated in cisplatin-treated mouse testes. The STRING database predicted that MT1 might be able to regulate the SIRT1/Nrf2 signaling pathway. Melatonin reduced oxidative stress and upregulated SIRT1/Nrf2 signaling in cisplatin-treated mouse testes and Leydig cells. Most importantly, after inhibiting MT1/MT2, melatonin could not upregulate SIRT1/Nrf2 signaling in cisplatin-treated Leydig cells. The MT1/MT2 inhibitor aggravated the cisplatin-induced downregulation of SIRT1/Nrf2 signaling and increased the apoptosis of Leydig cells. We believe that melatonin stimulates SIRT1/Nrf2 signaling by activating MT1/MT2 to prevent the cisplatin-induced apoptosis of Leydig cells.

Effect of NMDA receptor agonist and antagonist on spermatogonial stem cells proliferation in 2- and 3- dimensional culture systems

BACKGROUND

The main purpose of this study was to investigate the effect of D-serine (DS) and Dizocilpine (MK-801) on the proliferation of spermatogonial stem cells (SSCs) in two-dimensional (2D) and three-dimensional (3D) culture systems.

METHODS AND RESULTS

The SSCs of male NMRI mice were isolated by enzymatic digestion and cultured for two weeks. Then, the identity of SSCs was validated by anti-Plzf and anti-GFR-α1 antibodies via immunocytochemistry (ICC). The proliferation capacity of SSCs was evaluated by their culture on a layer of the decellularized testicular matrix (DTM) prepared from mouse testis, as well as two-dimensional (2D) with different mediums. After two weeks of the initiation of proliferation culture on 3D and 2D medium, the pre-meiotic at the mRNA and protein levels were evaluated via qRT-PCR and flow cytometry methods, respectively. The results showed that the proliferation rate of SSCs in 3D culture with 50 mM glutamic acid and 20 mM D-serine was significantly different from other groups after 14 days treatment. mRNA expression levels of promyelocytic leukemia zinc finger (Plzf) in 3D cultures supplemented by 20 mM D-serine and 50 mM glutamic acid were considerably higher than the 3D control group (p < 0.001). The flow cytometry analysis revealed that the amount of Plzf in the 2D-culture groups of SSCs with 20 mM MK-801 was considerably lower compared to the 2D-culture control group (p < 0.001).

CONCLUSIONS

This study indicated that decellularized testicular matrix supplemented with D-serine and glutamic acid could be considered a promising vehicle to support cells and provide an appropriate niche for the proliferation of SSCs.

Exogenous melatonin prevents type 1 diabetes mellitus-induced bone loss, probably by inhibiting senescence

Exogenous melatonin inhibited the senescence of preosteoblast cells in type 1 diabetic (T1D) mice and those cultured in high glucose (HG) by multiple regulations. Exogenous melatonin had a protective effect on diabetic osteoporosis, which may depend on the inhibition of senescence.

INTRODUCTION

Senescence is thought to play an important role in the pathophysiological mechanisms underlying diabetic bone loss. Increasing evidence has shown that melatonin exerts anti-senescence effects. In this study, we investigated whether melatonin can inhibit senescence and prevent diabetic bone loss.

METHODS

C57BL/6 mice received a single intraperitoneal injection of 160 mg/kg streptozotocin, followed by the oral administration of melatonin or vehicle for 2 months. Then, tissues were harvested and subsequently examined. MC3T3-E1 cells were cultured under HG conditions for 7 days and then treated with melatonin or not for 24 h. Sirt1-specific siRNAs and MT1- or MT2-specific shRNA plasmids were transfected into MC3T3-E1 cells for mechanistic study.

RESULTS

The total protein extracted from mouse femurs revealed that melatonin prevented senescence in T1D mice. The micro-CT results indicated that melatonin prevented bone loss in T1D mice. Cellular experiments indicated that melatonin administration prevented HG-induced senescence, whereas knockdown of the melatonin receptors MT1 or MT2 abolished these effects. Sirt1 expression was upregulated by melatonin administration but significantly reduced after MT1 or MT2 was knocked down. Knockdown of Sirt1 blocked the anti-senescence effects of melatonin. Additionally, melatonin promoted the expression of CDK2, CDK4, and CyclinD1, while knockdown of MT1 or MT2 abolished these effects. Furthermore, melatonin increased the expression of the polycomb repressive complex (PRC), but knockdown of MT1 or MT2 abolished these effects. Furthermore, melatonin increased the protein levels of Sirt1, PRC1/2 complex-, and cell cycle-related proteins.

CONCLUSION

This work shows that melatonin protects against T1D-induced bone loss, probably by inhibiting senescence. Targeting senescence in the investigation of diabetic osteoporosis may lead to novel discoveries.

p57 Suppresses the Pluripotency and Proliferation of Mouse Embryonic Stem Cells by Positively Regulating p53 Activation

Embryonic stem cells (ESCs) are pluripotent stem cells that have indefinite self-renewal capacities under appropriate culture conditions in vitro. The pluripotency maintenance and proliferation of these cells are delicately governed by the concert effect of a complex transcriptional regulatory network. Herein, we discovered that p57^Kip2 (p57), a cyclin-dependent kinase inhibitor canonically inhibiting cell proliferation, played a role in suppressing the pluripotency state of mouse ESCs (mESCs). p57 knockdown significantly stimulated the expressions of core pluripotency factors NANOG, OCT4, and SOX2, while p57 overexpression inhibited the expressions of these factors in mESCs. In addition, consistent with its function in somatic cells, p57 suppressed mESC proliferation. Further analysis showed that p57 could interact with and contribute to the activation of p53 in mESCs. In conclusion, the present study showed that p57 could antagonize the pluripotency state and the proliferation process of mESCs. This finding uncovers a novel function of p57 and provides new evidence for elucidating the complex regulatory of network of mESC fate.

Antioxidant and anti-inflammatory protective effects of rutin and kolaviron against busulfan-induced testicular injuries in rats

There are few treatment options, including the use of natural phenolics-based combination therapy for mitigating male infertility conditions associated with chemotherapy. Busulfan is an anti-cancer drug that leads to testicular problems in humans. Here, we studied the effect of co-treatment of rutin and kolaviron against busulfan-induced testis damage. Young adult male Wistar rats were intraperitoneally injected busulfan (4 mg/kg b.w), and then orally administered rutin (30 mg/kg b.w), and kolaviron (50 mg/kg b.w) alone and combined for 60 days. Results revealed that rutin and kolaviron alone or in combination reversed busulfan-induced increase in oxidative stress along with sperm quality of treated animals. However, kolaviron and rutin separately improved the concentrations of MDA and GSH and sperm quality more than when they were combined. Similarly, rutin and kolaviron separately or in combination preserved spermatogenesis and relieved busulfan-induced increase in nitric oxide concentration, myeloperoxidase and 3β-hydroxysteroid dehydrogenase activities. Co-supplementation with kolaviron but not rutin nor when rutin was combined with kolaviron also improved the testicular level of tumor necrosis-alpha. Finally, the histological features in the testes caused by busulfan were reversed by rutin, whereas treatment with kolaviron alone or in combination with rutin partially protected the testis from busulfan-induced injury as demonstrated by the appearance of few germ cells, damaged tubules, loss of round spermatids and defoliation of the seminiferous epithelium. Thus, the combined treatment regimen of rutin and kolaviron sparingly prevented busulfan-induced testicular injuries in rats.Abbreviations: CAT: Catalase; GSH: Glutathione; 3β-HSD: 3β- hydroxysteroid Dehydrogenase; MDA: Malondialdehyde; TNF-α: Tumor necrosis-alpha; BUS: Busulfan; RUT: Rutin; KV: Kolaviron; TBARS: Thiobarbituric Acid Reactive Substances; MPO: Myeloperoxidase; ELISA: Enzyme-Linked Immunoassay; NAD: Nicotinamide Adenine Dinucleotide (oxidized); ROS: Reactive Oxygen Species.

The potential neuroprotective effect of allicin and melatonin in acrylamide-induced brain damage in rats

Acrylamide (ACR) is an unsaturated monomer that served various fields; however, it is a potent neurotoxin. The target of the present study is to explore the neuroprotective efficacy of allicin and melatonin on ACR-induced neurotoxicity. Thirty-six male adult rats were non-selectively separated into six groups: placebo, allicin (20 mg/kg b.w daily per os), melatonin (10 mg/kg b.w 3 times/week per os), ACR (50 mg/kg b.w daily per os), ACR-allicin, and ACR-melatonin at the same doses as the preceding groups. The assessment of brain biomarkers, neurotransmitters, antioxidative status, Nrf2 signaling pathway, and histopathological analyses was performed following 21 days. ACR exposure induced brain lipid and DNA oxidative damage as well as reduced the glutathione (GSH) levels. The obvious brain oxidative injuries contributed to distinct brain dysfunction that was assured by alteration of brain neurotransmitters (serotonin, dopamine, acetylcholine, and acetylcholinesterase) and pathological brain lesions. Furthermore, ACR exposure increased hydroxy deoxyguanosine (8-OHdG), tumor necrosis factor-α (TNF-α), and amyloid protein (AB1-42). Finally, the mRNA transcripts of brain Keap-1, Nrf2, and NF-kB were upregulated after ACR intoxication. Interestingly, allicin and melatonin alleviated the ACR-induced brain damage assessed by the normalization of the mentioned analyses. The present study demonstrated the protective role of both allicin and melatonin in ACR-prompted neuropathy by alleviation of redox imbalance and enhancement of neurotransmitters as well as relieving DNA damage and anti-inflammatory effect.

Busulfan impairs blood-testis barrier and spermatogenesis by increasing noncollagenous 1 domain peptide via matrix metalloproteinase 9

BACKGROUNDS

Sterility induced by anti-cancer treatments has caused significant concern, yet the mechanism and treatment exploration are little for male infertility after cancer therapy. Busulfan, the antineoplastic that was widely applied before bone marrow transplantation, was known to induce male reproductive disorder.

OBJECTIVES

To investigate the effect of busulfan on blood-testis barrier function in adult rats and determine whether noncollagenous 1 domain peptide, the biologically active fragment proteolyzed from the collagen α3 chain (IV) by matrix metalloproteinase 9, was involved during this process.

MATERIALS AND METHODS

Adult male rats were treated with one-dose or double-dose of busulfan (10 mg/kg) before euthanized at day 35. Blood-testis barrier integrity assay, HE staining, immunofluorescence, and Western blot were used to validate the effect of busulfan on blood-testis barrier permeability and spermatogenesis. JNJ0966 was applied to specifically inhibit the matrix metalloproteinase 9 activity. The polymerization activity of F-actin/G-actin and microtubule/tubulin in the testis were assessed by using commercial kits.

RESULTS

A noteworthy blood-testis barrier injury and significant up-regulation of matrix metalloproteinase 9 activity and noncollagenous 1 level after a single-dose busulfan (10 mg/kg) treatment in adult rat testis were revealed. The application of JNJ0966 was found to decrease noncollagenous 1 level and rescue the busulfan-induced blood-testis barrier injury including the mis-localization of junction proteins across the seminiferous epithelium, by recovering the organization and polymerization of both F-actin and microtubule. The busulfan-induced spermatogenesis impairment was also improved by JNJ0966.

CONCLUSION

These findings thus demonstrate that the elevation in matrix metalloproteinase 9 and noncollagenous 1 might participate in busulfan-induced blood-testis barrier disruption in adult male rats. As such, busulfan-induced male infertility could possibly be managed through interventions on noncollagenous 1 production.

Analysis of the Reversible Impact of the Chemodrug Busulfan on Mouse Testes

Spermatogenesis is a process within the testis that leads to the production of spermatozoa. It is based on a population of spermatogonial stem cells, which have the capacity to self-renew and to differentiate throughout life to ensure the functions of reproduction are maintained. Male fertility disorders are responsible for half of the cases of infertility in couples worldwide. It is well known that cancer treatments are associated with reversible or irreversible fertility disorders. Busulfan (Bu) is an alkylating agent that significantly inhibits spermatogenesis. The present study relied on a combination of in vivo and in vitro approaches as well as RNAseq analysis to characterize the effects of Bu, in which mouse testes were used as a model. An in silico analysis revealed that many of the Bu-modulated genes are potentially regulated by the SIN3 Transcription Regulator Family Member A (SIN3A) and E2F Transcription Factor (E2F) families of transcription factors. The results demonstrate that the deregulated genes function in processes related to the cell cycle, DNA repair, and cell death mechanisms, including the Tumor Protein 53 (TP53) pathway. This reinforces the role of the TP53 signaling pathway as a major player in Bu effects. In addition, Bu altered the patterns of mRNA accumulation for various genes in undifferentiated spermatogonia. This work provides significant insight into the kinetics and impacts of busulfan, which could pave the way for developing strategies to minimize the impact of chemodrugs and, thus, could lead to germ cell lineage regeneration following anticancer treatments.

Melatonin ameliorates endocrine dysfunction and defective sperm integrity associated with high-fat diet-induced obesity in male Wistar rats

Obesity (OBS) has been established as a link to male hypogonadism with consequent infertility. Previous studies have shown that melatonin (MEL) modulates hypothalamic-pituitary-gonadal function. The present study therefore investigated the hypothesis that MEL supplementation would attenuate spermatogenic and steroidogenic dysfunctions associated with obesity induced by high-fat diet (HFD). Twenty-four adult male Wistar rats (n = 6/group) were used: control group received vehicle (normal saline), obese group received 40% high-fat diet and distilled water, MEL-treated group received MEL (4 mg/kg), and OBS + MEL group received MEL and 40% HFD and the treatment lasted for 12 weeks. HFD caused increased body weight, glucose intolerance, plasma triglyceride and low-density lipoprotein cholesterol/ very low-density lipoprotein cholesterol and malondialdehyde, as well as decreased antioxidant capacity, high-density lipoprotein cholesterol, gonadotrophin-releasing hormone, follicle-stimulating hormone and testosterone and altered sperm parameters. However, all these alterations were attenuated when supplemented with MEL. Taken together, these results indicate that HFD exposure causes endocrine dysfunction and disrupted sperm parameters in obese animals, which are accompanied by lipid peroxidation/defective antioxidant capacity. In addition, the present results suggest that melatonin supplementation restores endocrine function and sperm integrity in obese rat model by suppression of oxidative stress-dependent mechanism.

Busulfan Suppresses Autophagy in Mouse Spermatogonial Progenitor Cells via mTOR of AKT and p53 Signaling Pathways

In testis, a rare undifferentiated germ cell population with the capacity to regenerate robustly and support spermatogenesis, is defined as spermatogonial progenitor cells (SPCs) population. As a widely used drug for tumor therapy or bone marrow transplantation, busulfan has a severe side effect on SPCs population and causes a consequent infertility. Recently, accumulating evidence revealed the protective role of autophagy in stem cell maintenance under exogenous stress. To better understand the role of autophagy in SPCs fates, we investigated the potential function of autophagy in SPCs under busulfan stress, and found that treatment of busulfan induced the formation of autophagic vesicles and autophagosomes in mouse SPCs. Subsequently, a connection of autophagy and SPCs maintenance and survival was demonstrated in a dose-dependent manner. Moreover, mTOR was identified as an essential factor for autophagy in SPCs with a complicated mechanism: (1) mTOR is phosphorylated by AKT to activate its target genes, p70s6 kinase, resulting in the inhibition of autophagy during short-term busulfan treatment. (2) mTOR mediates autophagy with p53 together, to regulate the fate of SPCs. Collectively, observations from this study indicate that moderate autophagy effectively protects SPCs from the stress of chemotherapy, which may provide an important hint for fertility protection in clinic.

Transcriptome-wide m6A profiling reveals mRNA post-transcriptional modification of boar sperm during cryopreservation

Background

Cryopreservation induces transcriptomic and epigenetic modifications that strongly impairs sperm quality and function, and thus decrease reproductive performance. N⁶-methyladenosine (m⁶A) RNA methylation varies in response to stress and has been implicated in multiple important biological processes, including post-transcriptional fate of mRNA, metabolism, and apoptosis. This study aimed to explore whether cryopreservation induces m⁶A modification of mRNAs associated with sperm energy metabolism, cryoinjuries, and freezability.

Results

The mRNA and protein expression of m⁶A modification enzymes were significantly dysregulated in sperm after cryopreservation. Furthermore, m⁶A peaks were mainly enriched in coding regions and near stop codons with classical RRACH motifs. The mRNAs containing highly methylated m⁶A peaks (fts vs. fs) were significantly associated with metabolism and gene expression, while the genes with less methylated m⁶A peaks were primarily involved in processes regulating RNA metabolism and transcription. Furthermore, the joint analysis of DMMGs and differentially expressed genes indicated that both of these play a vital role in sperm energy metabolism and apoptosis.

Conclusions

Our study is the first to reveal the dynamic m⁶A modification of mRNAs in boar sperm during cryopreservation. These epigenetic modifications may affect mRNA expression and are closely related to sperm motility, apoptosis, and metabolism, which will provide novel insights into understanding of the cryoinjuries or freezability of boar sperm during cryopreservation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07904-8.

Melatonin relieves heat-induced spermatocyte apoptosis in mouse testes by inhibition of ATF6 and PERK signaling pathways

Normal spermatogenic processes require the scrotal temperature to be lower than that of the body as excessive heat affects spermatogenesis in the testes, reduces sperm quality and quantity, and even causes infertility. Endoplasmic reticulum stress (ERS) is a crucial factor in many pathologies. Although several studies have linked ERS to heat stress, researchers have not yet determined which ERS signaling pathways contribute to heat-induced testicular damage. Melatonin activates antioxidant enzymes, scavenges free radicals, and protects the testes from inflammation; however, few studies have reported on the influence of melatonin on heat-induced testicular damage. Using a murine model of testicular hyperthermia, we observed that heat stress causes both ERS and apoptosis in the testes, especially in the spermatocytes. These observations were confirmed using the mouse spermatocyte cell line GC2, where the Atf6 and Perk signaling pathways were activated during heat stress. Knockout of the above genes effectively reduced spermatocyte damage caused by heat stress. Pretreatment with melatonin alleviated heat-induced apoptosis by inhibiting the Atf6 and Perk signaling pathways. This mitigation was dependent on the melatonin receptors. In vivo experiments verified that melatonin treatment relieved heat-induced testicular damage. In conclusion, our results demonstrated that ATF6 and PERK are important mediators for heat-induced apoptosis, which can be prevented by melatonin treatment. Thus, our study highlights melatonin as a potential therapeutic agent in mammals for subfertility/infertility induced by testicular hyperthermia.

Astaxanthin Relieves Busulfan-Induced Oxidative Apoptosis in Cultured Human Spermatogonial Stem Cells by Activating the Nrf-2/HO-1 pathway

Many child cancer patients endure anticancer therapy containing alkylating agents before sexual maturity. Busulfan (BU), as an alkylating agent, is a chemotherapy drug, causing DNA damage and cytotoxicity in germ cells. In the present study, we aimed to investigate the protective effect of astaxanthin (AST), as a potent antioxidant and powerful reactive oxygen species (ROS) scavenger, on BU-induced toxicity in human spermatogonial stem cells. For this purpose, testes were obtained from four brain-dead donors. After tissue enzymatic digestions, testicular cells were cultured for 3 weeks for spermatogonial stem cell (SSC) isolation and purification. K562 cell line was cultured to survey the effect of AST on cancer treatment. The cultured SSCs and K562 cell line were finally treated with AST (10μM), BU (0.1nM), and AST+BU. The expression of NRF-2, HO-1, SOD2, SOD3, TP53, and apoptotic genes, including CASP9, CASP3, BCL2, and BAX, were assayed using real-time PCR. Moreover, ROS level in different groups and malondialdehyde level and total antioxidant capacity in cell contraction of SSCs were measured using ELISA. Data showed that AST significantly upregulated the expression of NRF-2 gene (P<0.001) and protein (P<0.005) and also significantly decreased the production of BU-induced ROS (P<0.001). AST activated the NRF-2/HO-1 pathway that could remarkably restrain BU-induced apoptosis in SSCs. Interestingly, AST upregulated the expression level of apoptosis genes in the K562 cell line. The results of this study indicated that AST reduces the side effects of BU on SSCs without interference with its chemotherapy effect on cancerous cells through modulation of the NRF-2/HO-1 and mitochondria-mediated apoptosis pathways.

Muscarinic acetylcholine receptor M5 is involved in spermatogenesis through the modification of cell-cell junctions

Muscarinic acetylcholine receptor (mAChR) antagonists have been reported to decrease male fertility; however, the roles of mAChRs in spermatogenesis and the underlying mechanisms are not understood yet. During spermatogenesis, extensive remodeling between Sertoli cells and/or germ cells interfaces takes place to accommodate the transport of developing germ cells across the blood-testis barrier (BTB) and adluminal compartment. The cell–cell junctions play a vital role in the spermatogenesis process. This study used ICR male mice and spermatogonial cells (C18-4) and Sertoli cells (TM-4). shRNA of control or M5 gene was injected into 5-week-old ICR mice testes. Ten days post-viral grafting, mice were deeply anesthetized with pentobarbital and the testes were collected. One testicle was fresh frozen for RNA-seq analysis or Western blotting (WB). The second testicle was fixed for immunofluorescence staining (IHF). C18-4 or TM-4 cells were treated with shRNA of control or M5 gene. Then, the cells were collected for RNA-seq analysis, WB, or IHF. Knockdown of mAChR M5 disrupted mouse spermatogenesis and damaged the actin-based cytoskeleton and many types of junction proteins in both Sertoli cells and germ cells. M5 knockdown decreased Phldb2 expression in both germ cells and Sertoli cells which suggested that Phldb2 may be involved in cytoskeleton and cell–cell junction formation to regulate spermatogenesis. Our investigation has elucidated a novel role for mAChR M5 in the regulation of spermatogenesis through the interactions of Phldb2 and cell–cell junctions. M5 may be an attractive future therapeutic target in the treatment of male reproductive disorders.

Redox signaling as a modulator of germline stem cell behavior: Implications for regenerative medicine

Germline stem cells (GSCs) are crucial for the generation of gametes and propagation of the species. Both intrinsic signaling pathways and environmental cues are employed in order to tightly control GSC behavior, including mitotic divisions, the choice between self-renewal or onset of differentiation, and survival. Recently, oxidation-reduction (redox) signaling has emerged as an important regulator of GSC and gamete behavior across species. In this review, we will highlight the primary mechanisms through which redox signaling acts to influence GSC behavior in different model organisms (Caenorhabditis elegans, Drosophila melanogaster and Mus musculus). In addition, we will summarize the latest research on the use of antioxidants to support mammalian spermatogenesis and discuss potential strategies for regenerative medicine in humans to enhance reproductive fitness.

Human placental mesenchymal stem cells ameliorate chemotherapy-induced damage in the testis by reducing apoptosis/oxidative stress and promoting autophagy

Background

The side effects of busulfan on male reproduction are serious, so fertility preservation in children undergoing busulfan treatment is a major worldwide concern. Human placental mesenchymal stem cells (hPMSCs) have advantages such as stable proliferation and lower immunogenicity that make them an ideal material for stimulating tissue repair, especially restoring spermatogenesis. The protective effects of hPMSCs in busulfan-induced Sertoli cells and in busulfan-treated mouse testes have not been determined. Our study aimed to elaborate the protective effect and potential mechanisms of hPMSCs in busulfan-treated testes and Sertoli cells.

Methods

First, we developed a mouse model of busulfan-induced testicular toxicity in vivo and a mouse Sertoli cell line treated with busulfan in vitro to assess the protective effect and mechanisms of hPMSC treatment on spermatogenesis. Then, the length, width, and weight of the testes were monitored using Vernier calipers. Furthermore, at 1 week and 4 weeks after the transplantation of hPMSCs, histological sections of testes were stained with hematoxylin-eosin, and the seminiferous tubules with fluid-filled cavities were counted. Through ELISA analysis, testosterone levels and MDA, SOD, LDH, and CAT activities, which are associated with ROS, were detected. Markers of ROS, proliferation (Ki67), and apoptosis (Annexin V) were evaluated by FACS. Next, the fluorescence intensity of proliferation markers (BrdU and SCP3), an antioxidant marker (SIRT1), a spermatogenesis marker (PLZF), and autophagy-related genes (P62 and LC3AB) were detected by fluorescence microscopy. The mRNA expression of γ-H2AX, BRCA1, PARP1, PCNA, Ki67, P62, and LC3 was determined by qRT-PCR.

Results

hPMSCs restored disrupted spermatogenesis, promoted improved semen parameters, and increased testosterone levels, testis size, and autophagy in the testis toxicity mouse model induced by busulfan. hPMSCs suppressed the apoptosis of Sertoli cells and enhanced their rate of proliferation in vitro. Additionally, hPMSCs protected against oxidative stress and decreased oxidative damage in the testis toxicity mouse model induced by busulfan. Furthermore, hPMSCs increased the expression of proliferation genes (PCNA and KI67) and decreased the mRNA levels of apoptotic genes such as γ-H2AX, BRCA1, and PARP1.

Conclusions

This research showed that hPMSC injection ameliorated busulfan-induced damage in the testis by reducing apoptosis/oxidative stress and promoting autophagy. The present study offers an idea for a new method for clinical treatment of chemotherapy-induced spermatogenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02275-z.

The Therapeutic Potential of Amniotic Fluid-Derived Stem Cells on Busulfan-Induced Azoospermia in Adult Rats

BACKGROUND

Busulfan is an alkylating chemotherapeutic agent that is routinely prescribed for leukemic patients to induce myelo-ablation. However, it also results in azoospermia and infertility in cancer survivors. This research was constructed to explore the possible therapeutic role of amniotic fluid-derived stem cells (AFSCs) in improving busulfan-induced azoospermia in adult rats.

METHODS

Forty two adult male albino rats were randomized into: (1) control group, (2) azoospermia group, (3) spontaneous recovery group, and (4) AFSCs-treated group, in which AFSCs were transplanted through their injection into the testicular efferent ducts. The assessment included a histo-pathological examination of the seminiferous tubules by the light and transmission electron microscopes. Additionally, the confocal laser scanning microscope was used for confirmation of homing of the implanted cells. Moreover, we conducted an immuno-fluorescence study for detection of the proliferating cell nuclear antigen (PCNA) in the spermatogenic cells, epididymal sperm count, and a histo-morphometric study.

RESULTS

AFSCs successfully homed over the basement membrane of the injured seminiferous tubules. They greatly attenuated busulfan-induced degenerative and oxidative changes. They also caused a re-expression of PCNA in the germ cells, leading to resumption of spermatogenesis and re-appearance of spermatozoa.

CONCLUSION

AFSCs could be a promising treatment modality for male infertility induced by chemotherapy, as they possess prominent regenerative, anti-apoptotic, and anti-inflammatory potentials.

Establishing a nonlethal and efficient mouse model of male gonadotoxicity by intraperitoneal busulfan injection

An ideal animal model of azoospermia would be a powerful tool for the evaluation of spermatogonial stem cell (SSC) transplantation. Busulfan has been commonly used to develop such a model, but 30%–87% of mice die when administered an intraperitoneal injection of 40 mg kg⁻¹. In the present study, hematoxylin and eosin staining, Western blot, immunofluorescence, and quantitative real-time polymerase chain reaction were used to test the effects of busulfan exposure in a mouse model that received two intraperitoneal injections of busulfan at a 3-h interval at different doses (20, 30, and 40 mg kg⁻¹) on day 36 or a dose of 40 mg kg⁻¹ at different time points (0, 9, 18, 27, 36, and 63 days). The survival rate of the mice was 100%. When the mice were treated with 40 mg kg⁻¹ busulfan, dramatic SSC depletion occurred 18 days later and all of the germ cells were cleared by day 36. In addition, the gene expressions of glial cell line-derived neurotrophic factor (GDNF), fibroblast growth factor 2 (FGF2), chemokine (C-X-C Motif) ligand 12 (CXCL12), and colony-stimulating factor 1 (CSF1) were moderately increased by day 36. A 63-day, long-term observation showed the rare restoration of endogenous germ cells in the testes, suggesting that the potential period for SSC transplantation was between day 36 and day 63. Our results demonstrate that the administration of two intraperitoneal injections of busulfan (40 mg kg⁻¹ in total) at a 3-h interval to mice provided a nonlethal and efficient method for recipient preparation in SSC transplantation and could improve treatments for infertility and the understanding of chemotherapy-induced gonadotoxicity.

β-carotene Rescues Busulfan Disrupted Spermatogenesis Through Elevation in Testicular Antioxidant Capability

β-carotene, precursor of vitamin A, is an excellent antioxidant with many beneficial properties. It is a lipid-soluble antioxidant and a very effective quencher of reactive oxygen species (ROS) to reduce the oxidative stress. In contrast to vitamin A, β-carotene is not toxic even consumed in higher amount when it is delivered from natural plant products. Recently, we found that β-carotene acts as a potential antioxidant in the oocyte to improve its quality. Even though many studies have been reported that β-carotene has the beneficial contribution to the ovarian development and steroidogenesis, it is unknown the effects of β-carotene on the spermatogenesis. This investigation aimed to explore the hypothesis that β-carotene could improve spermatogenesis and the underlying mechanism. And we found that β-carotene rescued busulfan disrupted spermatogenesis in mouse with the increase in the sperm concentration and motility. β-carotene improved the expression of genes/proteins important for spermatogenesis, such as VASA, DAZL, SYCP3, PGK2. Moreover, β-carotene elevated the testicular antioxidant capability by the elevation of the antioxidant glutathione and antioxidant enzymes SOD, GPX1, catalase levels. In conclusion, β-carotene may be applied for the infertile couples by the improvement of spermatogenesis, since, worldly many couples are infertile due to the idiopathic failed gametogenesis (spermatogenesis).

Effect of a Freezing Medium Containing Melatonin on Markers of Pre-meiotic and Post-meiotic Spermatogonial Stem Cells (SSCs) After Transplantation in an Azoospermia Mouse Model Due to Testicular Torsion

Spermatogonial stem cells (SSCs) are essential to the initiation of spermatogenesis. Cryopreservation, long-term maintenance, and auto-transplantation of SSCs could be a new treatment for infertility. The aim of this study was to add melatonin to the basic freezing medium and to evaluate its effect on the efficiency of the thawed SSCs after transplantation into the testicles of azoospermic mice. SSCs were isolated from newborn NMRI mice, and the cells were enriched to assess morphological features. The thawed SSCs were evaluated for survival, apoptosis, and ROS level before transplantation, and the proliferation (MVH and ID4) and differentiation (c-Kit, SCP3, TP1, TP2, and Prm1) markers of SSCs were examined using immunofluorescence, western blot, and quantitative real-time polymerase chain reaction (PCR) after transplantation. It was found that the survival rate of SSCs after thawing was significantly higher in the melatonin group compared with the cryopreservation group containing basic freezing medium, and the rate of apoptosis and level of ROS production also decreased significantly in the cryopreservation group with melatonin (p < 0.05). The expression of proliferation and differentiation markers after transplantation was significantly higher in the cryopreservation group with melatonin compared to the cryopreservation group (p < 0.05). The results suggest that adding melatonin to the basic freezing medium can effectively protect the SSCs by increasing the viability and reducing the ROS production and apoptosis and improve the transplantation efficiency of SSCs after cryopreservation, which will provide a significant suggestion for fertility protection in the clinic.

Melatonin Protects Goat Spermatogonial Stem Cells against Oxidative Damage during Cryopreservation by Improving Antioxidant Capacity and Inhibiting Mitochondrial Apoptosis Pathway

Spermatogonial stem cells (SSCs) are the only adult stem cells that pass genes to the next generation and can be used in assisted reproductive technology and stem cell therapy. SSC cryopreservation is an important method for the preservation of immature male fertility. However, freezing increases the production of intracellular reactive oxygen species (ROS) and causes oxidative damage to SSCs. The aim of this study was to investigate the effect of melatonin on goat SSCs during cryopreservation and to explore its protective mechanism. We obtained SSCs from dairy goat testes by two-step enzymatic digestion and differential plating. The SSCs were cryopreserved with freezing media containing different melatonin concentrations. The results showed that 10⁻⁶ M of melatonin increased significantly the viability, total antioxidant capacity (T-AOC), and mitochondrial membrane potential of frozen-thawed SSCs, while it reduced significantly the ROS level and malondialdehyde (MDA) content (P < 0.05). Further analysis was performed by western blotting, flow cytometry, and transmission electron microscopy (TEM). Melatonin improved significantly the enzyme activity and protein expression of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) (P < 0.05), thereby activating the antioxidant defense system of SSCs. Furthermore, melatonin inhibited significantly the expression of proapoptotic protein (Bax) and increased the expression of antiapoptotic proteins (Bcl-2 and Bcl-XL) (P < 0.05). The mitochondrial apoptosis pathway analysis showed that the addition of melatonin reduced significantly the mitochondrial swelling and vacuolation, and inhibited the release of cytochrome C from mitochondria into the cytoplasm, thereby preventing the activation of caspase-3 (P < 0.05) and inhibiting SSC apoptosis. In addition, melatonin reduced significantly the autophagosome formation and regulated the expression of autophagy-related proteins (LC3-I, LC3-II, P62, Beclin1, and ATG7) (P < 0.05), thereby reversing the freeze-induced excessive autophagy. In summary, melatonin protected goat SSCs during cryopreservation via antioxidant, antiapoptotic, and autophagic regulation.

Prolonged melatonin treatment promote testicular recovery by enhancing RAC1-mediated apoptotic cell clearance and cell junction-dependent spermatogensis after heat stress

INTRODUCTION

A decline in semen quality caused by global warming and torrid working conditions is a major cause of human male infertility, and heat stress-induced decreases in male reproductive ability results in economic losses in livestock husbandry. Increasing evidence suggests that melatonin exerts protective effects on stress-induced DNA damage and apoptosis in germ cells. However, few studies have assessed the effects of melatonin on testicular recovery during post-heat stress and the underlying mechanisms.

METHODS AND RESULTS

In vivo studies using 8-week-old male CD-1 mice revealed that melatonin pretreatment (50 mg/kg for 5 days) did not alleviate heat stress-induced germ cell loss and disrupted testicular histomorphology, however, long-term melatonin administration after heat stress accelerated germ cell apoptosis, spermatogenic cell regeneration, and testicular weight recovery. In vitro studies demonstrated that melatonin enhanced RAC1 activity, resulting in increased phagocytosis of apoptotic germ cells by Sertoli cells. In addition, melatonin restored gap junctions and tight junctions after heat stress, thereby promoting hollow seminiferous tubule filling.

DISCUSSION

Long-term melatonin administration accelerated testicular recovery after heat stress by enhancing the phagocytotic activity of Sertoli cells and the regeneration of spermatogenic cells. This finding suggests that melatonin is a potential therapeutic for heat stress-induced male infertility.

Melatonin protects mouse testes from palmitic acid-induced lipotoxicity by attenuating oxidative stress and DNA damage in a SIRT1-dependent manner

Palmitic acid (PA), the main component of dietary saturated fat, has been known to increase in patients with obesity, and PA-induced lipotoxicity may contribute to obesity-related male infertility. Melatonin has beneficial effects on reproductive processes; however, the effect and the underlying molecular mechanism of melatonin's involvement in PA-induced cytotoxicity in the testes are poorly understood. Our findings showed that lipotoxicity was observed in mouse testes after long-term PA treatment and that melatonin therapy restored spermatogenesis and fertility in these males. Moreover, melatonin therapy suppressed PA-induced apoptosis by modulating apoptosis-associated proteins such as Bcl2, Bax, C-Caspase3, C-Caspase12, and CHOP in type B spermatogonial stem cells. Changes in the expression of endoplasmic reticulum (ER) stress markers (p-IRE1, p-PERK, ATF4) and intracellular Ca²⁺ levels showed that melatonin relieved PA-induced ER stress. Mechanistically, melatonin stimulated the expression and nuclear translocation of SIRT1 through its receptors and prevented PA-induced ROS production and mitochondrial dysfunction via SIRT1 signaling pathway. Furthermore, melatonin promoted SIRT1-mediated p53 deacetylation, thereby relieving G2/M arrest in response to PA-stimulated DNA damage. Collectively, these findings indicate that melatonin protects the testes from PA-induced lipotoxicity through the activation of SIRT1, which alleviates oxidative stress, ER stress, mitochondrial dysfunction, and DNA damage.

Effect of Gosha-Jinki-Gan on Levels of Specific mRNA Transcripts in Mouse Testes after Busulfan Treatment

With the increase in survival rates of cancer patients in recent years, infertility caused by anticancer treatments has become a significant concern for cancer survivors. Some studies have suggested that Sertoli cells play a key role in mediating testicular immunology in busulfan-induced aspermatogenesis. We recently demonstrated that Gosha-jinki-gan (TJ107), a traditional Japanese medicine, can completely recover injured spermatogenesis in mice 60 days after busulfan injection. In the present study, we sought to examine the levels of mRNA transcripts encoding markers of 25 Sertoli cell-specific products and 10 markers of germ cell differentiation. Our results demonstrated that only supplementation of TJ107 at day 60 after busulfan injection could significantly recover the increase in five mRNA species (Amh, Clu, Shbg, Testin, and Il1a) and the decrease in four mRNA species (Aqp8, CST9, Wnt5a, and Tjp1) in response to Busulfan (BSF) at day 120, with the increase of all examined spermatogenic markers.

Melatonin alleviates LPS-induced endoplasmic reticulum stress and inflammation in spermatogonial stem cells

Orchitis is one of the leading causes of male animal infertility and is associated with inflammatory reactions caused by the bacterium. It has been reported that there is a mutual coupling effect between endoplasmic reticulum stress (ERS) and inflammatory response. Our studies showed that lipopolysaccharide (LPS) could cause testicular damages, apoptosis, ERS, and inflammatory responses in spermatogonial stem cells (SSCs); ERS-related apoptosis proteins were activated and the expression of ERS genes was significantly upregulated; meanwhile, the expression of Toll-like receptor 4 and inflammation factors was apparently increased with LPS treatment. Moreover, melatonin (MEL) could rescue testicular damage, and significantly inhibited the expression of ERS-related apoptosis genes, ERS markers, and inflammatory factors in SSCs and MEL played repairing and anti-infection roles in LPS-induced testicular damage. Therefore, MEL may be used as a drug to prevent and control bacterial infections in male reproductive systems. However, the specific molecular mechanism of MEL to resist ERS and inflammatory response remains to be further studied.

Melatonin daily oral supplementation attenuates inflammation and oxidative stress in testes of men with altered spermatogenesis of unknown aetiology

We have previously shown an inverse correlation between testicular melatonin concentration and inflammation/oxidative stress-related markers levels in infertile men showing unexplained azoospermia. Here, we evaluated the impact of melatonin oral supplementation (daily 3 mg dose used to treat sleep disorders) in the incidence of local inflammation, oxidative stress, and tubular wall fibrosis development in young and middle-aged infertile adult men. Compared with testes without histological alterations, gonads with morphological abnormalities showed lower melatonin concentration along with increased macrophage numbers, TBARS generation, and expression levels of inflammation-related markers and antioxidant enzymes, as well as tubular wall collagen fibers disorganization and thickening. Melatonin oral supplementation not only increased its own testicular levels but also decreased inflammation- and oxidative stress-related markers levels, and improved the tubular wall aspect. Overall, our work provides insights into the potential benefits of melatonin on the inflammatory and oxidative status in testes of patients suffering from unexplained infertility.

Melatonin ameliorates murine fetal oocyte meiotic dysfunction in F1 and F2 offspring caused by nicotine exposure during pregnancy

Although there is abundant evidence to demonstrate that maternal smoking during pregnancy will harm the health of future generations, the impact of nicotine use by pregnant woman upon the oogenesis and folliculogenesis of female offspring has not been as widely scrutinized. Here we focus on the effects of nicotine on the meiotic progression of fetal oocytes. The data indicated that in pregnant mice treated with nicotine, intracellular ROS increased in follicles within the fetal ovary. Excessive intracellular hydrogen peroxide (H₂O₂) and superoxide anion (O₂^-) decreased mitochondrial membrane potential, inducing mitochondrial dysfunction, triggering an autophagic cascade and inhibiting anti-autophagic proteins. Fetal oocytes in F1 offspring of pregnant mice treated with nicotine exhibited a delay in meiotic prophase I, especially from the stage of pachytene to diplotene. In pubertal F1 offspring we observed a reduced number of follicles; the same reduction was also observed in F2 offspring. Of note, we found that melatonin ameliorated nicotine-induced oocyte damage and increased the expression of MnSOD, which decreased the production of nicotine-induced intracellular ROS. In addition, melatonin also maintained normal H3K4 and H3K9 di- and tri-methylation in F1 and F2 ovaries. Taken together, the current evidence suggests that, in the mouse, melatonin could prevent nicotine-impaired fetal oogenesis and folliculogenesis in offspring.

Human amnion mesenchymal stem cells restore spermatogenesis in mice with busulfan-induced testis toxicity by inhibiting apoptosis and oxidative stress

Background

Before starting gonadotoxic therapies, cryopreservation of mature sperm has been proposed worldwide as a method for male fertility preservation and for enabling the conception of a healthy baby with assisted reproductive technology (ART); however, these technologies are not feasible for prepubertal boys and men with spermatogenic failure. Transplantation of mesenchymal stem cells has exhibited successful therapeutic benefits in restoring spermatogenesis via gonadal graft angiogenesis, transplanted cell clonogenesis, and disordered somatic compartment recovery. This study aimed to elucidate the fertility protective effects and the underlying mechanisms of human amnion mesenchymal stem cells (hAMSCs) against busulfan-induced testis toxicity.

Methods

An in vivo busulfan-induced testis toxicity mouse model and an in vitro busulfan-administered mouse Sertoli cell line were employed to evaluate the efficacy and mechanisms of hAMSC transplantation on male fertility preservation. The process of spermatogenesis was evaluated histologically, and the percentage of seminiferous tubules with vacuoles was evaluated by HE staining. Semen parameters were calculated by computer-assisted semen analysis. ELISA was employed to test the testosterone concentration and the levels of oxidative- and antioxidative-associated substances LDH, MDA, GR, SOD, GPx, and CAT. The rates of proliferation (Ki67), apoptosis (Annexin V), and ROS were measured by FACS. The fluorescence intensity of a marker of apoptosis (TUNEL) and a meiosis gene in spermatogenesis (SCP3) were detected by immunofluorescence assay. The expression of mRNA in germ cell-specific (GCS) genes (Dazl, Ddx4, and Miwi) and meiosis genes (Scp3, Cyclin A1, and Stra8) was tested by qPCR. The expression of antiapoptotic proteins (SURVIVIN and BCL2), apoptotic proteins (CASPASE3 and CASPASE9), GCS proteins (Dazl, Ddx4, and Miwi), and meiosis proteins (Scp3, Cyclin A1, and Stra8) was tested by western blotting.

Results

hAMSC transplantation following disruption by busulfan-induced testis toxicity restored spermatogenesis, elevating testosterone levels and enhancing testicular weight, size, and semen parameters in vivo. In addition, hAMSCs clearly ameliorated cell apoptosis, enhanced cell proliferation, repressed oxidative damage, and augmented oxidative defense in vivo and in vitro. Moreover, hAMSCs distinctly increased the expression of the GCS genes Dazl, Ddx4, and Miwi and the meiosis genes Scp3, Cyclin A1, and Stra8 in vivo.

Conclusions

hAMSCs might represent a promising tool for the use in regenerative medicine, as these cells can restore spermatogenesis in a busulfan-induced testis toxicity mouse model and facilitate activity in a busulfan-administered mouse Sertoli cell line by resisting apoptosis and oxidative stress.

Septin4 regulates endoplasmic reticulum stress and apoptosis in melatonin‑induced osteoblasts

Idiopathic scoliosis (IS) is a spinal 3-dimensional deformity with an unknown cause. Melatonin is secreted by the pineal body and contributes to the occurrence and progression of IS. In our previous preliminary study, it was reported that high concentrations of melatonin can induce osteoblast apoptosis, thus acting as an IS treatment, but the mechanism of action is unknown. Therefore, the present study was performed to further investigate the possible mechanism underlying the efficacy of melatonin as a treatment for IS. The present results indicated that high concentrations of melatonin mediate endoplasmic reticulum stress (ERS)-induced apoptosis in hFOB 1.19 cells, and this resulted in a significant and dose-dependent increase in the expression of Septin4, as well as the expression levels of glucose-regulated protein (GRP)78, GRP94 and cleaved caspase-3. Furthermore, osteoblasts were overexpressed with Septin4 and the mechanism via which melatonin induces osteoblast ERS was demonstrated to be via the regulation of Septin4. In addition, it was indicated that cytoskeleton destruction, cell morphology changes and the decrease in the number of cells were aggravated after osteoblasts were overexpressed with Septin4, as indicated by phalloidin and DAPI staining. Collectively, the present results suggest that the Septin4 protein may be a target of ERS in melatonin-induced osteoblast apoptosis, which is involved in bone metabolism diseases, thus providing novel evidence for clinical melatonin treatment of IS.

Thymus vulgaris Attenuates Myleran-induced Reproductive Damage by Decreasing Oxidative Stress and Lipid Peroxidation in Male Rats

Context:

Thymus vulgaris is an herbal with potent antioxidant and it has been shown to have beneficial effects during short-term administration. Myleran (MYL) is used for treatment of certain types of tumors. MYL produces free radicals and induces disturbance in sperm parameters.

Aims:

This study is designed to assess the effects of T. vulgaris against damage to the male rats' reproductive features induced by MYL.

Subjects and Methods:

Sixty-four male Wistar rats were randomly assigned into eight groups: control group; MYL (10 mg/kg) group; T. vulgaris groups (4.5, 9, and 18 mg/kg); and MYL (10 mg/kg) + T. vulgaris groups (4.5, 9, and 18 mg/kg; separately). Treatments were administered daily intraperitoneal injection for 60 days. Total antioxidant capacity, sperm factors, malondialdehyde (MDA), testosterone, and germinal layer height were analyzed.

Results:

Whole variables of MYL group decreased signifcantly compared to the control group (P < 0.05) except MDA level (which increased). The T. vulgaris and T. vulgaris + MYL treatments in all doses increased all parameters significantly except MDA level (which decreased) compared to the MYL group (P < 0.05). No significant modifications were observed in all T. vulgaris groups compared to the control group (P > 0.05).

Conclusions:

T. vulgaris reduces the poisonous properties of MYL on male reproductive factors.

Inhibiting Necroptosis of Spermatogonial Stem Cell as a Novel Strategy for Male Fertility Preservation

Fertility preservation is a common concern for male cancer survivors of reproductive age. However, except for testicular tissue cryopreservation, which is not very effective, there is no feasible and precise therapy capable of protecting spermatogenesis for prepubertal boys before or during gonadotoxic treatment. This study aims to investigate the effects of inhibiting necroptosis of spermatogonial stem cell (SSC) in fertility preservation. Male mice 12 weeks of age were used to establish gonadotoxicity with two intraperitoneal injections of busulfan at a total dose of 40 mg kg^-1. The mouse model and the primary cultured mouse SSCs were used to characterize the relationship between necroptosis of SSC and gonadotoxicity. Meanwhile, the effects of an inhibitor of necroptosis pathway, RIPA-56, were observed on day 36 in the mouse model of busulfan-induced gonadotoxicity. We found that the number of SSCs was decreased, but the level of necroptosis was upregulated on day 18 after busulfan treatment in testes from gonadotoxic mice. Further experiments in primary cultured cells showed that the necroptosis caused cell death in busulfan-treated SSCs and could be inhibited by RIPA-56. After suppressing the necroptosis of SSCs, the busulfan-induced mice had a decreased loss of spermatogenic cells as shown by histology and an increased Johnsen's score. Moreover, the quantities of SSCs and epididymal spermatozoa were restored after intervention with RIPA-56, indicating a series of beneficial effects by targeting the necroptosis of SSCs in mice undergoing busulfan treatment. In conclusion, our findings reveal that the necroptosis of SSCs plays a critical role in busulfan-induced gonadotoxicity and may be a potential target for male fertility preservation.

Co-Administration of the Traditional Medicines Hachimi-Jio-Gan and Hochu-Ekki-To Can Reverse Busulfan-Induced Aspermatogenesis

Busulfan is used as a chemotherapeutic drug to treat childhood and adult chronic myelogenous leukemia, and as an immunosuppressive agent before bone marrow transplantation. A key side effect of busulfan is the alteration of male reproductive function. Infertility caused by anti-cancer treatments has become a significant concern, but there are currently limited treatments for this condition. Recently, we demonstrated that Gosha-jinki-gan, a traditional Japanese medicine, completely reversed the spermatogenesis defects caused by cancer treatment in mice. Hochu-ekki-to and Hachimi-jio-gan are commonly used to treat male infertility, and Hachimi-jio-gan shares herbal ingredients with Gosha-jinki-gan. Therefore, in the present study, we administered Hachimi-jio-gan and Hochu-ekki-to alone or in combination to mice with severe aspermatogenesis caused by busulfan treatment. We performed testis weight measurements, quantitative histological assessments of the testes and the epididymis, and evaluated sperm counts and morphology. We also assessed the expression of immune mediators and macrophage markers. Treatment with a combination of both the medicines significantly reduced busulfan-induced testicular toxicity when compared to the lone treatment with either medicine. We demonstrated that treatment efficacy was related to a differential impact on testicular inflammation, and that the synergistic effect of co-administration completely reversed the busulfan-induced damage to the reproductive functions.