Effects of ascorbic acid on spermatogenesis and sperm parameters in diabetic rats

The relevance of the use of plant extracts on testicular cells: A systematic review

This review aims to establish an association between traditional and scientific knowledge to allow the evaluation of the effectiveness of medicinal plants, as well as their risks based on the testicular microenvironment. A systematic search was performed using PRISMA guidelines. The descriptors were structured based on search filters built for three domains: Animals, Plants, and Testis. The filters on the PubMed/Medline platform were constructed using a hierarchical distribution of the MeSH Terms. Methodological quality assessments were performed using the SYRCLE risk bias tool. Data on testicular cells, hormones and biochemistry, sperm, and sexual behavior were evaluated and compared. The search came out with 2644 articles, and 36 articles met the inclusion criteria and were used in this review. The included studies analyzed testicular cells from murine models treated with crude plant extracts. Plant extracts act directly on the hypothalamic-pituitary axis and/or directly on testicular cells, inhibiting and stimulating the reproductive process, thus causing alterations in fertility rates. Apiaceae and the Cucurbitaceae families are the most used in male reproductive biology experiments, being Apiaceae described as sexual stimulants, while Cucurbitaceae are the main sources of deleterious effects on the male reproductive system.

Vitamin C supplementation rescued meiotic arrest of spermatocytes in Balb/c mice exposed to BDE-209

Deca-brominated diphenyl ether (BDE-209) is a ubiquitous industrial chemical as brominated flame retardant (BFRs). Exposure to BDE-209 has been clearly associated with male reproductive disorders. However, the meiotic arrest mechanism of spermatocytes exposed to BDE-209 is still unclear. The present work aimed to explore the protective effect of vitamin C on BDE-209-induced meiotic arrest of spermatocytes and its possible mechanism. Vitamin C (100 mg/kg BW) was administered to BDE-209-exposed (80 mg/kg BW) male Balb/c mice once daily by intraperitoneal injection for 2 weeks. Our results showed that vitamin C played male reproductive protection effects as showed by attenuated BDE-209-induced testicular damage, and reduced sperm abnormality rate. Vitamin C also attenuated BDE-209-induced increase in SOD and MDA in testes and GC-2 spd cells. Moreover, vitamin C promoted meiotic prophase in BDE-209-induced mice, with suppressed γ-H2AX, restored DMC1, RAD51, and crossover marker MLH1 levels, and prevented BDE-209-induced DNA impairment. In addition, vitamin C supplementation also interfered with BDE-209-induced upregulation of testicular H3K4me3 through inhibition of KDM5s capacity and decreasing ferrous ion concentration. Furthermore, ferrous sulfate pretreatment could partially restore the expression of H3K4me3 via maintaining the concentration of ferrous ions. Taken together, vitamin C exerts a potential therapeutic agent for preventing BDE-209-induced reproductive toxicity with meiotic arrest, which is attributed to its antioxidant and electron donor properties, as well as, modulation of ferrous ion levels and demethylation of H3K4me3.

Investigating the therapeutic options for diabetes-associated male infertility as illustrated in animal experimental models

Diabetes is a rising global health concern and an increasingly common cause of male infertility. Although the definitive pathophysiological mechanisms underpinning the association between diabetes and infertility is unclear, there are several animal studies showing diabetes to be a detrimental factor on reproductive health through apoptosis, oxidative stress and impairment of steroidogenesis. Furthermore, as reflected in animal models, antidiabetic strategies and relevant treatments are beneficial in the management of infertile men with diabetes as the recovery of euglycemic status affects positively the spermatogenesis. However, the available data are still evolving and specific conclusion in human populations are not possible yet. In this review, we are discussing the current literature concerning the association of diabetes and male infertility, focusing on the therapeutic approach as illustrated in animals' models.

Reduction in Glomerular and Renal Tubular Damage in Kidneys of Diabetic Rats Supplemented with Alpha-Lipoic Acid

Chronic hyperglycemia caused by diabetes results in systemic damage to the body, and the kidney ends up being the target of tissue damage. The use of antioxidants such as alpha-lipoic acid (ALA) has been shown to improve clinical and biochemical parameters in diabetic patients as they help in the prevention of oxidative stress. The present study aimed to undertake a comparative evaluation of the renal morphology of normal and diabetes-induced Wistar rats supplemented with ALA. The experiment had 4 experimental groups (n=7): a control group and a diabetic group that were fed commercial food; an alpha-lipoic group and an alpha-lipoic diabetic group that received the ALA supplement. Diabetes was induced with a single intraperitoneal injection of alloxane monohydrate administered after fasting. After 60 days of the experiment, the kidneys were excised to study the histomorphometric and stereological parameters of the glomeruli and renal tubules and the immunohistochemical parameters with a podocyte count. In the evaluation, the ALA promoted improvement in all of the relevant parameters of the glomerular areas and attenuation of tubular lesions of diabetic animals (p<0.001). Supplementation with ALA also showed beneficial effects in diabetic animals, such as reducing hyperglycemia and the damage promoted by oxidative stress alongside promoting a protective effect on the renal parenchyma. The reduction of glomerular and tubular damage delayed the advance of diabetic nephropathy and its complications, preventing renal failure in diabetic groups.

A study of the aphrodisiac properties of Cordyceps militaris in streptozotocin-induced diabetic male rats

Background and Aim:

Cordyceps militaris (CM) is a fungus that has been used to enhance aphrodisiac activity in men, but to date, no studies have focused on its antidiabetic properties. This study aimed to investigate the effects of CM on reproductive performance of streptozotocin (STZ)-induced diabetic male rats.

Materials and Methods:

Six-week-old Wistar rats were randomly divided into four groups: control Group 1 consisting of healthy rats; Group 2, healthy rats treated with CM (100 mg/kg); Group 3, diabetic untreated rats; and Group 4, diabetic rats treated with CM (100 mg/kg). Rats were orally administered with vehicle or CM for 21 days. The body weight, blood glucose level, food intake, epididymal sperm parameter, sexual behavior, serum testosterone level, and antioxidant parameters were determined.

Results:

The results indicated that CM treatment in STZ-induced diabetic rats significantly improved the epididymal sperm parameter and serum testosterone level and, in turn, their copulatory behavior. CM treatment in diabetic rats significantly ameliorated malondialdehyde level and significantly improved the glutathione and catalase levels.

Conclusion:

These results provide new information on the pharmacological properties of CM in ameliorating testicular damage due to oxidative stress and improving sexual performance in diabetic male rats.

Roles of CatSper channels in the pathogenesis of asthenozoospermia and the therapeutic effects of acupuncture-like treatment on asthenozoospermia

Rationale: Idiopathic asthenozoospermia (iAZS) is one of the major causes of male infertility and has no effective therapeutic treatment. Understanding the potential mechanisms that cause it may be helpful in seeking novel targets and treatment strategies for overcoming the problem of low sperm motility in iAZS individuals.

Methods: Computer-assisted semen analysis (CASA) was utilized to assess the sperm motility. RT-qPCR, Western blot, immunofluorescence staining, and calcium imaging analysis were performed to examine the expression and function of CatSper channels. Hyperactivation and acrosome reaction were used to evaluate the functional characteristics of epididymal sperm. In vivo fertility assay was applied to determine the fertility of rats. CatSper1 knockdown and overexpression experiments were performed to confirm the roles of CatSper channels in the pathogenesis of iAZS and the therapeutic effects of electroacupuncture (EA) treatment on AZS model rats.

Results: Here, we reported a functional down-regulation of CatSper channel from CatSper1 to CatSper 4 in the sperm of both iAZS patients and ornidazole (ORN)-induced AZS model rats, and an impaired sperm function characterized by a reduction of protein tyrosine phosphorylation, hyperactivation, and acrosome reaction in the epididymal sperm of AZS rats. Knockdown of CatSper1 in the testis tissues is sufficient to induce AZS in normal rats, and this action was validated by the reversal effects of CatSper1 overexpression. Transcutaneous electrical acupoint stimulation (TEAS) and electroacupuncture (EA) at 2 Hz frequency improve the sperm motility via enhancing the functional expression of CatSper channels in the sperm. Gene silencing CatSper1 in the sperm abolishes the therapeutic effects of 2 Hz-EA treatment on AZS rats.

Conclusions: We conclude that a functional down-regulation of CatSper channel in the sperm may be a contributor or a downstream indicator for a portion of AZS, especially iAZS, while 2 Hz-TEAS or EA treatment has a therapeutic effect on iAZS through inducing the functional up-regulation of CatSper channels in the sperm. This study provides a novel mechanism for the pathogenesis of some AZS especially iAZS, and presents a potential therapeutic target of CatSper for iAZS treatment. Acupuncture treatment like TEAS may be used as a promising complementary and alternative medicine (CAM) therapy for male infertility caused by iAZS in clinical practice.

Diabetes-induced testicular oxidative stress, inflammation, and caspase-dependent apoptosis: the protective role of metformin

Context: Metformin's effect on glycaemic control is well documented, but its effect on diabetes-induced testicular impairment has been scarcely reported.Objective: To investigate the effects of metformin on testicular oxidative stress, inflammation, and apoptosis, which largely contribute to fertility decline in diabetic state.Methods: Male Sprague-Dawley rats were divided into 3 groups (n = 6/group) namely: normal control (NC), diabetic control (DC), and metformin (300 mg/kg b.w./d)-treated diabetic groups. Metformin was administrated for 4 weeks.Results: Decreased mRNA expressions and activities of antioxidant enzymes were seen in the testes of DC group. mRNA and protein expressions of pro-inflammatory and pro-apoptotic markers increased, while interleukin-10 and proliferating cell nuclear antigen (PCNA) decreased in the testes of DC group. Treatment with metformin up-regulated antioxidant enzymes, down-regulated inflammation, and apoptosis and increased PCNA immunoexpression in the testes.Conclusions: Metformin protects the testes from diabetes-induced impairment and may improve male reproductive health in diabetic state.

Ascorbic acid promotes the reproductive function of porcine immature Sertoli cells through transcriptome reprogramming

Vitamin C (ascorbic acid, AA) can regulate antioxidation and affect many cellular processes. However, the effect of AA on the reproduction of male animals remains less explored. Here, we showed that by supplementing exogenous AA to porcine immature Sertoli cells (iSCs), AA could promote the proliferation, suppress apoptosis, and decrease the global nucleic acid methylation (5 mC and m⁶A) levels of iSCs. After we profiled mRNA and long non-coding RNA (lncRNA) expression by transcriptome sequencing on iSCs (treated by 250 μM AA for 36 h), 1232 mRNAs and 937 lncRNAs were identified to be differentially expressed (DE). Gene enrichment analysis found multiple significantly enriched biological pathways, including oxidoreductase activity, cell proliferation and apoptosis, regulation of hormone level, regulation of catalytic activity, developmental process, ATP metabolism and reproductive process. Specifically, for the reproductive process, 49 up- and 36 down-regulated DE mRNAs (including highly expressed genes, such as Tfcp2l1, Hmgcs1, Mmp7, Fndc3a, and Zfp36l1) are involved. Moreover, AA supplementation could promote the secretion of anti-müllerian hormone, inhibin B and lactate, and enhance the activity of lactate dehydrogenase as well. Taken together, AA could promote the reproductive function of pig iSCs, potentially through reprogramming the global transcriptome, and elevating hormone secretion and metabolite production.

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AA could promote the proliferation, suppress apoptosis, and decrease the global nucleic acid mthylation levels of iSCs.

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AA treatment changed mRNA and lncRNA profiles of iSCs.

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AA treatment significantly disturbed the expression of mRNAs (such as Tfcp2l1, Hmgcs1, Mmp7, Fndc3a, and Zfp36l1) involved in reproductive process.

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AA supplement could promote the secretion of anti-mullerian hormone, inhibin B and lactate, and the activity of lactate dehydrogenase as well.

Loganin alleviates testicular damage and germ cell apoptosis induced by AGEs upon diabetes mellitus by suppressing the RAGE/p38MAPK/NF-κB pathway

Diabetes mellitus (DM) damages male reproduction at multiple levels, such as endocrine secretion, spermatogenesis and penile erection. We herein investigated the protective effects and mechanism of loganin targeting the advanced glycation end products (AGEs)/receptor for AGEs (RAGE)/p38 mitogen-activated protein kinase (p38MAPK)/NF-κB signalling pathway. Loganin relieved the general DM symptoms and decreased the blood glucose level of KK-Ay DM mice. Haematoxylin-eosin staining demonstrated that loganin ameliorated testicular histology and function and enhanced the activities of testis-specific markers lactate dehydrogenase (LDH), acid phosphatase (ACP) and gamma-glutamyl transferase (γ-GT). Loganin also showed evident anti-oxidative stress, anti-apoptotic and anti-inflammatory effects on DM-induced reproductive damage by restoring glutathione (GSH) level and superoxide dismutase (SOD) activity, as well as reducing reactive oxygen species (ROS) level and Bax/Bcl-2 ratio in vivo and in vitro. Western blotting exhibited that loganin significantly inhibited the AGEs/RAGE/p38MAPK/NF-κB signalling pathway. Acridine orange and ethidium bromide staining (AOEB) and Western blotting showed that loganin in combination with inhibitors of RAGE, p38MAPK and NF-κB exerted stronger anti-apoptotic effects on AGE-induced GC-2 cell damage compared with loganin alone. In conclusion, loganin can protect against DM-induced reproductive damage, probably by suppressing the AGEs/RAGE/p38MAPK/NF-κB pathway.

Oxidative stress and male infertility: current knowledge of pathophysiology and role of antioxidant therapy in disease management

Infertility is a global health problem involving about 15% of couples. Approximately half of the infertility cases are related to male factors. The oxidative stress, which refers to an imbalance in levels of reactive oxygen species (ROS) and antioxidants, is one of the main causes of infertility in men. A small amount of ROS is necessary for the physiological function of sperm including the capacitation, hyperactivation and acrosomal reaction. However, high levels of ROS can cause infertility through not only by lipid peroxidation or DNA damage but inactivation of enzymes and oxidation of proteins in spermatozoa. Oxidative stress (OS) is mainly caused by factors associated with lifestyle. Besides, immature spermatozoa, inflammatory factors, genetic mutations and altering levels of sex hormones are other main source of ROS. Since OS occurs due to the lack of antioxidants and its side effects in semen, lifestyle changes and antioxidant regimens can be helpful therapeutic approaches to overcome this problem. The present study aimed to describe physiological ROS production, roles of genetic and epigenetic factors on the OS and male infertility with various mechanisms such as lipid peroxidation, DNA damage, and disorder of male hormone profile, inflammation, and varicocele. Finally, the roles of oral antioxidants and herbs were explained in coping with OS in male infertility.

Exposure of Fluoride with Streptozotocin-Induced Diabetes Aggravates Testicular Damage and Spermatozoa Parameters in Mice

Diabetes mellitus is the most common chronic disease worldwide that causes numerous complications, including male infertility. The prevalence of DM is 451 million people and estimated that would increase to 693 million in 2045. Fluorosis caused by drinking water contaminated with inorganic fluoride is a public health problem in many areas around the world. Previous studies have shown that fluoride exposure damages the male reproductive function. This study aimed to evaluate the fluoride sub-chronic exposure on the spermatozoa function in streptozotocin (STZ)-induced diabetic mice. After confirming diabetes by measuring blood glucose levels, the male mice received 45.2 ppm of fluoride added or deionized water. We evaluated several parameters in diabetic mice exposed to fluoride: standard quality analysis, the mitochondrial transmembrane potential (ψm), the caspase activity in spermatozoa, urinary fluoride excretion, and histological evaluation in the testes. After 60 days of fluoride-exposure, diabetic mice, significantly decreased sperm quality (motility, viability, and concentration). Spermatozoa from fluoride-exposure in diabetic mice presented a significant decrease in ψm and a significant increase in activity caspase 3/7. Urinary fluoride excretion was decreased in diabetic mice exposed to fluoride. Subchronic fluoride exposure of mice with STZ-induced diabetes aggravated testicular damage and the spermatozoa function.

Antioxidant action of alpha lipoic acid on the testis and epididymis of diabetic rats: morphological, sperm and immunohistochemical evaluation

Introduction

Chronic hyperglycemia is caused by diabetes mellitus-committed genital morphophysiology, and oxidative stress is one of the main factors involved in this process. Alpha lipoic acid (ALA) can prevent metabolic and morphological changes in diabetic individuals.

Objectives

In present study, we evaluated the effects of regular ALA consumption on the spermatogenesis and histoarchitecture in the male genital system of diabetic rats.

Materials and Methods

Thirty-two Wistar rats were divided into groups: Control (CG); Diabetic Control (DCG), receiving commercial diet: ALA Group (ALAG) and Diabetic ALA Group (DALAG), fed diets with added ALA (300 mg/Kg bw). The diabetic groups received a single injection of streptozotocin (60 mg/kg). After sixty days of the diet, the animals were euthanized, and semen, testis and epididymis samples were collected. A histomorphometric analysis was performed to determine the epithelial height, tubular and luminal diameter, tubular and luminal area of seminiferous tubules and each epididymal region. Sertoli cells were evidenced using the antivimenti antibody and were quantified. The results were statistically analyzed by the ANOVA test.

Results

At the end of the experiment, the DALAG glycemia was significantly lower than DCG. The histomorphometric parameters of the seminiferous and epididymal tubules did not show improvement in the DALAG. However, there was an improvement in the DALAG in terms of the concentration, motility and percentage of spermatic pathologies, as well as in the number of Sertoli cells (p<0.001).

Conclusions

The results demonstrated that supplementation with the ALA antioxidant retards testicular lesions and preserve the process of spermatogenesis in diabetes.

Protective Effect of Vitamin C on Triptolide-induced Acute Hepatotoxicity in Mice through mitigation of oxidative stress

Triptolide, a purified diterpenoid from the herb Tripterygium wilfordii Hook.f., was widely used to treat many diseases. However, the hepatotoxicity of triptolide limited its clinical use. Research showed oxidative stress played an important role in triptolide-induced liver injury. To investigate the effect of vitamin C, which was one of the most effective antioxidants, on triptolide-induced hepatotoxicity and its potential mechanism in mice. In the present study, acute liver injury was induced by intraperitoneal injection of triptolide and vitamin C was orally administered. The results showed treatment with vitamin C prevented the triptolide-induced liver injury by reducing the levels of aspartate transaminase from 286.86 to 192.48 U/mL and alanine aminotransferase from 746.75 to 203.36 U/mL. Histopathological changes of liver corresponded to the same trend. Furthermore, vitamin C also protected the liver against triptolide-induced oxidative stress by inhibiting the generation of malondialdehyde (2.22 to 1.49 nmol/mgprot) and hydrogen peroxide (14.74 to 7.19 mmol/gprot) and restoring the level of total superoxide dismutase (24.32 to 42.55 U/mgprot) and glutathione (7.69 to 13.03 μg/mgprot). These results indicated that vitamin C could protect against triptolide-induced liver injury via reducing oxidative stress, and vitamin C may pose a significant health protection in the clinical use of triptolide.

Isolation, characterization, and therapeutic activity of bergenin from marlberry (Ardisia colorata Roxb.) leaf on diabetic testicular complications in Wistar albino rats

Bergenin is one of the phytochemical constituents in marlberry (Ardisia colorata Roxb.) having antioxidant, anti-diabetic, and anti-inflammatory properties. A. colorata has been used as an herbal medicine in Southeast Asia particularly in Northeast India to treat diabetes. Bergenin was isolated from methanol extract of A. colorata leaf (MEACL) by column chromatography and TLC profiling. Characterization and structural validation of bergenin were performed by spectroscopic analyses. A LC-ESI-MS/MS method was developed for the quantitation of bergenin and validated as per the guidelines of FDA and EMA. The validated method was successfully utilized to quantify bergenin concentration in MEACL samples. Therapeutic efficacy of bergenin was investigated on streptozotocin-induced diabetic rats by following standard protocols. Bergenin supplementation significantly improved the physiological and metabolic processes and in turn reverses diabetic testicular dysfunction via increasing serum testosterone concentrations and expression pattern of PCNA, improving histopathological and histomorphometric manifestations, modulating spermatogenic events and germ cell proliferation, restoring sperm quality, reducing sperm DNA damage, and balancing the antioxidant enzymes levels. Hence, A. colorata leaf is one of the alternate rich resources of bergenin and could be used as a therapeutic agent for diabetic testicular complications.

The protective effect of vitamin C on phenylhydrazine-induced hemolytic anemia on sperm quality and in-vitro embryo development in mice

Background

Phenylhydrazine (PHZ) induced anemia and was shown to have harmful effects on the male reproductive system.

Objective

To investigate the protective effect of vitamin C (Vit C) on sperm parameters quality, in vitro fertilization potential and embryonic development in a mouse model of hemolytic anemia induced by PHZ.

Materials and Methods

Thirty-two NMRI adult male mice (n = 8/each) were randomly classified into four groups. Group I (control) received normal saline, Group II (PHZ) received 8 mg/100 gr body weight PHZ as initial dose, continued by 6 mg/100 gr intraperitoneally every 48 hr, Group III (Vit C) received Vit C (10 mg/kg, daily, intraperitoneally), and group IV (PHZ + Vit C) received PHZ and Vit C. After 35 days, sperm quality parameters, the percentage of sperm with DNA damage and in vitro fertilization outcomes up to blastocyst stage were evaluated.

Results

A significant (p < 0.001) reduction in all of the sperm parameters (count, motility, viability and normal morphology) were observed in group II (PHZ) compared with group I (control). In group IV (PHZ ± Vit C), these parameters and sperm DNA damage (p < 0.001) improved significantly when compared with PHZ-treated mice. Furthermore, PHZ caused a significant (p < 0.001) decrease in the fertilization rate and the percentage of pre-implantation embryos' (two cell embryo and blastocyst) formation in comparison to group I (control), and Vit C supplementation in mice of group IV improved significantly the fertilization rate (p = 0.002), but it could not improve the percentage of two cell embryos and blastocyst production.

Conclusion

The data from this study indicated that Vit C decreased the adverse effects of PHZ on the quality of sperm parameters and in vitro fertilization rate, but it is insufficient to restore the in-vitro embryonic development and fertility potential.