Testicular toxicity and sperm quality following copper exposure in Wistar albino rats: ameliorative potentials of L-carnitine

Association of urinary metal element with semen quality: a cross-sectional study from Eastern China

The effect of metallic elements on semen quality remains controversial, with limited evidence on the effects of metal mixtures. We conducted a study involving 338 participants from multiple centers in Eastern China, measuring 17 urinary metals and semen quality parameters. Our analysis used various statistical models, including multivariate logistic and linear regression, Bayesian Kernel Machine Regression, and weighted quantile sum models, to examine the associations between metal levels and semen quality. Logistic regression showed that higher urinary lead was associated with increased risk of abnormal sperm concentration (OR = 1.86, p = 0.021), arsenic to higher abnormal progressive motility risk (OR = 1.49, p = 0.027), and antimony to greater abnormal total motility risk (OR = 1.37, p = 0.018). Conversely, tin was negatively correlated with the risk of abnormal progressive motility (OR = 0.76, p = 0.012) and total motility (OR = 0.74, p = 0.003), respectively. Moreover, the linear models showed an inverse association between barium and sperm count, even after adjusting for other metals (β = - 0.32, p < 0.001). Additionally, the WQS models showed that the metal mixture may increase the risk of abnormal total motility (βWQS = 0.55, p = 0.046). In conclusion, semen quality may be adversely affected by exposure to metals such as arsenic, barium, lead, and antimony. The combined effect of the metal mixture appears to be particularly impaired total motility.

A metabolomic perspective on the mechanisms by which environmental pollutants and lifestyle lead to male infertility

The incidence of male infertility (MI) is rising annually. According to epidemiological studies, environmental pollution (e.g., organic, inorganic, and air pollutants), occupational exposure (e.g., high temperature, organic solvents, and pesticides), and poor lifestyle (e.g., diet, sleep, smoking, alcohol consumption, and exercise) are important non-genetic causative factors of MI. Due to multiple and complex causative factors, the dose-effect relationship, and the uncertainty of pathogenicity, the pathogenesis of MI is far from fully clarified. Recent data show that the pathogenesis of MI can be monitored by the metabolites in serum, seminal plasma, urine, testicular tissue, sperm, and other biological samples. It is considered that these metabolites are closely related to MI phenotypes and can directly reflect the individual pathological and physiological conditions. Therefore, qualitative and quantitative analysis of the metabolome, the related metabolic pathways, and the identification of biomarkers will help to explore the MI-related metabolic problems and provide valuable insights into its pathogenic mechanisms. Here, we summarized new findings in MI metabolomics biomarkers research and their abnormal metabolic pathways triggered by the presented non-genetic risk factors, providing a metabolic landscape of semen and seminal plasma in general MI patients. Then, we compared the similarities and differences in semen and seminal plasma biomarkers between MI patients exposed to environmental and poor lifestyle factors and MI patients in general, and summarized some common biomarkers. We provide a better understanding of the biological underpinnings of MI pathogenesis, which might offer novel diagnostic, prognostic, and precise treatment approaches to MI.

Cuproptosis mediates copper-induced testicular spermatogenic cell death

Cuproptosis, a novel mechanism of programmed cell death, has not been fully explored in the context of spermatogenic cells. This study investigated the potential involvement of cuproptosis in spermatogenic cell death using a mouse model of copper overload. Sixty male Institute of Cancer Research (ICR) mice were randomly divided into four groups that received daily oral gavage with sodium chloride (control) or copper sulfate (CuSO4) at 50 mg kg-1, 100 mg kg-1, or 200 mg kg-1, for 42 consecutive days. Mice subjected to copper overload exhibited a disruption in copper homeostasis. Additionally, significant upregulated expression of key cuproptosis factors was accompanied by a significant rise in the rates of testicular tissue cell apoptosis. Immunohistochemical analysis revealed the presence of ferredoxin 1 (Fdx1) in Sertoli cells, Leydig cells, and spermatogenic cells at various stages of testicular development, and the Fdx1-positive staining area was significantly increased in copper-overloaded mice. Mitochondrial dysfunction and decreased adenosine triphosphate levels were also observed, further implicating mitochondrial damage under cuproptosis. Further analyses revealed pathological lesions and blood-testis barrier destruction in the testicular tissue, accompanied by decreased sperm concentration and motility, in copper-overloaded mice. In summary, our results indicate that copper-overloaded mice exhibit copper homeostasis disorder in the testicular tissue and that cuproptosis participates in spermatogenic cell death. These findings provide novel insights into the pathogenic mechanisms underlying spermatogenic cell death and provide initial experimental evidence for the occurrence of cuproptosis in the testis.

L-Carnitine and Male Fertility: Is Supplementation Beneficial?

L-Carnitine, a natural antioxidant found in mammals, plays a crucial role in the transport of long-chain fatty acids across the inner mitochondrial membrane. It is used as a nutritional supplement by professional athletes, improving performance and post-exercise recovery. Additionally, its therapeutic applications, including those in male infertility, have been investigated, as it may act as a defense mechanism against the excessive production of reactive oxygen species (ROS) in the testis, a process that can lead to sperm damage. This effect is achieved by enhancing the expression and activity of enzymes with antioxidant properties. Nevertheless, the mechanisms underlying the benefits of L-Carnitine remain unknown. This review aims to consolidate the current knowledge about the potential benefits of L-Carnitine and its role in male (in)fertility. Considering in vitro studies with Sertoli cells, pre-clinical studies, and investigations involving infertile men, a comprehensive understanding of the effects of L-Carnitine has been established. In vitro studies suggest that L-Carnitine has a direct influence on somatic Sertoli cells, improving the development of germ cells. Overall, evidence supports that L-Carnitine can positively impact male fertility, even at a relatively low dose of 2 g/day. This supplementation enhances sperm parameters, regulates hormone levels, reduces ROS levels, and subsequently improves fertility rates. However, further research is needed to elucidate the underlying mechanisms and establish optimal doses. In conclusion, the role of L-Carnitine in the field of male reproductive health is highlighted, with the potential to improve sperm quality and fertility.

Polystyrene nanoparticles enhance the adverse effects of di-(2-ethylhexyl) phthalate on male reproductive system in mice

Coexposure of nanoplastics (NPs) with other pollutants adsorbed from the surroundings has received extensive attention. Currently, the combined effects of NPs and plasticizers remain unclear. Di-(2-ethylhexyl) phthalate (DEHP) is a commonly used plasticizer that has raised much concern owing to its ubiquitous pollution and endocrine-disrupting potential. This study aimed to investigate the toxic effects on the male reproductive system upon coexposure to NPs and DEHP. The C57BL/6J mice were orally administrated with polystyrene nanoparticles (PSNPs), DEHP or both for 35 days to evaluate their effects on sperm quality, histology of testes and epididymides, testicular transcriptomic characteristics as well as expression of some important genes in the epididymides. The low-dose PSNPs used here did not induce significant changes in sperm quality, while DEHP alone or cotreatment with DEHP and PSNPs caused notable impairment, mainly manifesting as decreased sperm quality and aberrant structure of the testis and epididymis. Moreover, enhanced toxic effects were found in the cotreatment group when compared with the individual DEHP treatment group, as manifested by more obvious alterations in the sperm parameters as well as histological changes in the testis and epididymis. Testicular transcriptomic analysis revealed differential regulation of genes involved in immune response, cytoplasmic pattern recognition receptor signaling pathways, protein ubiquitination, oxidative stress, necrotic cell death, ATP synthesis and the cellular respiratory chain. RT-qPCR verified that the expression patterns of Cenpb, Crisp1 and Mars were changed in testes, and genes relevant to epididymal function including Aqp9 and Octn2 were downregulated in epididymides, particularly in the cotreatment group. Collectively, our results emphasize that DEHP at an environmentally relevant dose can induce male reproductive toxicity, and PSNPs may aggravate the toxic effects.

Sub-chronic restraint stress exposure in adult rats: An insight into possible inhibitory mechanism on testicular function in relation to germ cell dynamics

Psychological stress is now widely recognized as one of the major risk factors for male fertility. Its impact on the dynamics of testicular germ cells, however, has yet to be fully investigated. Therefore, we used the rat restraint stress (RS) model as a psychological stressor to assess the impact of psychological stress on testicular germ cell dynamics. Adult male SD rats were exposed to sub-chronic RS for 1.5 and 3 h per day for 30 days. The quality of cauda epididymis spermatozoa was adversely affected by RS exposure, and the frequency of spermatozoa with tail abnormalities was higher than that of spermatozoa with head abnormalities. RS exposure adversely affected testicular daily sperm production by disturbing the meiotic and post meiotic germ cell kinetics in the testis. The histomorphology of the testis was altered by loosening and vacuolization in the seminiferous epithelium, germ cell exfoliation and the presence of giant cells. Seminiferous tubules of stage I-VI and VII-VIII were severely affected in rats exposed to RS for 3 h. By interfering with steroidogenic enzymes, RS exposure disrupts testosterone biosynthesis. The testicular oxidative balance was also disturbed by RS exposure, which disrupted the levels/activities of lipid peroxidation, Nrf-2, superoxide dismutase and catalase. There was also an increase in caspase-3 activity and a decrease in the Bax-Bcl2 ratio. In conclusion, our findings suggest that psychological stressors like RS impair testicular functions in rats by disrupting germ cell dynamics, downregulating testicular androgenesis and increasing oxidative stress and apoptosis.

Nano-Curcumin Prevents Copper Reproductive Toxicity by Attenuating Oxidative Stress and Inflammation and Improving Nrf2/HO-1 Signaling and Pituitary-Gonadal Axis in Male Rats

Copper is essential for several cellular processes and is an important catalytic factor for many proteins. However, excess copper can provoke oxidative stress and reproductive toxicity. This study evaluated the effect of liposomal nano-curcumin (N-CUR) and CUR on testicular oxidative injury, inflammation, and apoptosis, and altered steroidogenesis and Nrf2/HO-1 signaling induced by copper sulfate (CuSO4). Rats received CuSO4 and N-CUR or CUR via oral gavage for 7 days. CuSO4 induced histopathological changes and altered pituitary-gonadal axis manifested by decreased serum gonadotropins and testosterone. Testicular steroidogenesis genes (StAR, 3β-HSD, CYP17A1, and 17β-HSD) and androgen receptor (AR) were downregulated in rats that received CuSO4. N-CUR and CUR prevented testicular tissue injury, increased circulating FSH, LH, and testosterone, and upregulated testicular steroidogenesis genes and AR. Additionally, N-CUR and CUR decreased testicular MDA, NO, NF-κB, iNOS, TNF-α, Bax, and caspase-3 while enhanced Bcl-2, Nrf2, and the antioxidants GSH, HO-1, SOD, and catalase. In conclusion, N-CUR and CUR prevented CuSO4-induced reproductive toxicity in male rats by suppressing oxidative injury and inflammatory response and boosting steroidogenesis, sex hormones, and Nrf2/HO-1 signaling. N-CUR was more effective in ameliorating tissue injury, oxidative stress, inflammation, and apoptosis and enhancing steroidogenesis and Nrf2/HO-1 than the native form.

Treatment of copper nanoparticles (CuNPs) for two spermatogenic cycles impairs testicular activity via down-regulating steroid receptors and inhibition of germ cell proliferation in a mice model

Although copper is an indispensable trace metal for biological functions, its excess exposure causes hazardous effects on health. Copper in the form of nanoparticles (CuNPs) is widely used at present and therefore, the living organism is at continuous risk of its adverse effect. The prolonged treatment of CuNPs has not been evaluated yet on the male reproductive system. To demonstrate the combined adverse effects and the mechanism of copper nanoparticles (CuNPs), three doses of CuNPs, 10, 100 and 200 mg/kg were orally given to mice for 70 days. The present study demonstrated that CuNPs decreased the sperm quality parameters, male circulating hormones, induces testicular damages, increased oxidative stress, apoptosis, decreases antioxidant enzymes, germ cell proliferation, and increases the expression of 8-oxoguanine DNA glycosylase-1 (OGG1), apelin receptor (APJ) as well. CuNPs also down-regulated the expression of AR and Erα in the testis. These results suggest that CuNPs manifested their adverse effect on testis via modulating steroid and cytokine (apelin) receptors. The adverse effect of testis was most pronounced at the highest dose (200 mg/kg) of CuNPs, however, other doses show a less toxic effect on various parameters. In conclusion, results indicated that CuNPs may impair spermatogenesis via oxidative stress-mediated DNA damage and germ cell apoptosis at high doses.

Histopathological and Biochemical Comparative Study of Copper Oxide Nanoparticles and Copper Sulphate Toxicity in Male Albino Mice Reproductive System

Copper (Cu) is an essential trace element for the efficient functioning of living organisms. Cu can enter the body in different ways, and when it surpasses the range of biological tolerance, it can have negative consequences. The use of different nanoparticles, especially metal oxide nanoparticles, is increasingly being expanded in the fields of industry and biomedical materials. However, the impact of these nanoparticles on human health is still not completely elucidated. This comparative study was conducted to evaluate the impacts of copper oxide nanoparticles (CuO NPs) and copper sulphate (CuSO₄ 0.5 (H₂O)) on infertility and reproductive function in male albino mice BALB/c. Body weight, the weight of male reproductive organs, malondialdehyde (MDA) level, caspase-3 level, and the presence of Ki67 and CD68, as detected using the amino-histochemistry technique, were investigated. Animals were treated with 25 and 35 mg/kg of CuO NPs and CuSO₄ 0.5 (H₂O) by oral gavage for 14 days. The control group was given distilled water by oral gavage. Body weight significantly decreased at the end of experiments in both treated groups in a concentration- and time-dependent manner compared with the control group. Weights of testes and epididymis (head and tail), as well as the weight of the seminal vesicle, showed a significant decrease compared with the control. However, the average weights of the seminal vesicle and prostate significantly increased. Caspase-3 and MDA levels increased in the CuO NP and CuSO₄ 0.5 (H₂O) groups compared with the control group, and there was a significant difference between the two concentrations used. Immunohistochemical results detected a significant decrease in Ki67 protein in the treatment groups compared with the control. However, increase in CD68 protein was found in groups treated with CuO NPs and CuSO₄ 0.5 (H₂O) compared with the control group. Overall, this in vivo comparative study of CuO NPs and CuSO₄ 0.5 (H₂O) showed that oral intake of copper NPs at 25 and 23 mg/kg was safer to the mice reproductive system than CuSO₄ 0.5 (H₂O) at the same dose. CuSO₄ 0.5 (H₂O) significantly influenced the histopathological and toxicological alteration responses.

Induction of autophagy via the ROS-dependent AMPK-mTOR pathway protects copper-induced spermatogenesis disorder

Copper (Cu) is a necessary micronutrient at lower concentration, while excessive Cu exposure or Cu homeostasis disorders can lead to toxicity. The mechanism of male reproductive toxicity induced by Cu is still unknown. This study aims to investigate whether autophagy plays an important role in copper-induced spermatogenesis disorder in vivo and vitro. The present study showed that copper sulfate (CuSO₄) might significantly promote autophagy level in the testis and mouse-derived spermatogonia cell line GC-1 spg cells. Concurrently, CuSO₄ could induce autophagy via AMPK-mTOR pathway that downregulated p-mTOR/mTOR and subsequently upregulated p-AMPKα/AMPKα as well as p-ULK1/ULK1. In the meanwhile, CuSO₄ treatment could also increase expression levels of the autophagy-related proteins. Then, the role of oxidative stress in CuSO₄-induced autophagy was investigated. The findings demonstrated that oxidative stress inhibitor (NAC) attenuated CuSO₄-induced autophagy in vivo and vitro, reversing the activation for AMPK-mTOR pathway. Additionally, the study also investigated how autophagy worked under the spermatogenesis disorder induced by CuSO₄. Inhibition of autophagy could decrease cell viability, and enhance the ROS accumulation and apoptosis in the GC-1 cells, meanwhile, the spermatogenesis disorder, oxidative stress and histopathological changes were increased in the testis. Furthermore, co-treatment with the apoptosis inhibitor (Z-VAD-FMK) could decrease the spermatogenesis disorder but not influence autophagy. Besides, the crosslink between autophagy and ferroptosis were also measured, the data showed that inhibition of autophagy could suppress CuSO₄-induced ferroptosis in in vivo and vitro. Altogether, abovementioned results indicated that CuSO₄ induced autophagy via oxidative stress-dependent AMPK-mTOR pathway in the GC-1 cells and testis, and autophagy activation possibly led to the generation of protection mechanism through oxidative damage and apoptosis inhibition, however, autophagy also aggravate CuSO₄ toxicology through promoting ferroptosis. Overall, autophagy plays a positive role for attenuating CuSO₄-induced testicular damage and spermatogenesis disorder. Our study provides a possible targeted therapy for Cu overload-induced reproduction toxicology.

Autophagy and apoptosis mediated nano-copper-induced testicular damage

Nano-copper has been increasingly employed in various products. In previous studies, we showed that nano-copper caused damage in the rat testis, but it remains unclear whether the toxic reaction can affect the reproductive function. In this study, following 28 d of exposure to nano-copper at a dose of 44, 88, and 175 mg/kg/day, there was a decrease in sperm quality, fructose content, and the secretion of sex hormones. Nano-copper also increased the level of oxidative stress, sperm malformation rate, and induced abnormal structural changes in testicular tissue. Moreover, Nano-copper upregulated the expression of apoptosis-related protein Bax and autophagy-related protein Beclin, and downregulated the expression of Bcl2 and p62. Furthermore, nano-copper (175 mg/kg) downregulated the protein expression of AMPK, p-AKT, mTOR, p-mTOR, p-4E-BP1, p70S6K, and p-p70S6K, and upregulated the protein expression of p-AMPK. Therefore, nano-copper induced damage in testicular tissues and spermatogenesis is highly related to cell apoptosis and autophagy by regulating the Akt/mTOR signaling pathway. In summary, excess exposure to nano-copper may induce testicular apoptosis and autophagy through AKT/mTOR signaling pathways, and damage the reproductive system in adult males, which is associated with oxidative stress in the testes.

Chrysin and flunixin meglumine mitigate overloaded copper-induced testicular and spermatological damages via modulation of oxidative stress and apoptosis in rats

This study aimed to evaluate the possible protective actions of chrysin and flunixine meglumine on testicular and spermatological injuries experimentally stimulated by copper. We separated 36 male Sprague-Dawley rats into six equal groups: control, chrysin, flunixine meglumine, copper, copper +chrysin and copper +flunixine meglumine. Chrysin (50 mg/kg/bw/po), flunixine meglumine (2.2 mg/kg/bw/ip) and copper (500 mg/kg/bw/po) were administered day to day for 21 days. Copper administration caused significant morphological, physiological and biochemical alterations compared to the control group, which are as follows: production of oxidative stress, thanks to rise in testis lipid peroxidation and fall in antioxidant enzyme concentrations, decrease in sperm quality and increase in morphologic sperm abnormalities, suppression of spermatogenesis and prominent alterations in the testis histomorphology and induction of apoptosis in the testis tissues. On the other hand, compared to the copper group, treatment with chrysin or flunixine meglumine significantly attenuated these alterations. In conclusion, chrysin and flunixine meglumine have benefits such as antioxidant, antiapoptotic and anti-inflammatory against copper-induced testicular and spermatological damages in rats via the modulation of oxidative stress and apoptosis. Consequently, chrysin is a natural product which has comparable therapeutic actions to flunixine meglumine on the male reproductive system.

Cordycepin, a major bioactive component of Cordyceps militaris, ameliorates diabetes-induced testicular damage through the Sirt1/Foxo3a pathway

Diabetes-induced male dysfunction is considered as a worldwide challenge, and testicular damage mainly caused by oxidative stress is its most common manifestation. Cordycepin, a natural antioxidant, has been used in the treatment of diabetic complications. However, the protective action and underlying mechanism of cordycepin on hyperglycaemia-induced testicular damage are unclear. This study aimed to investigate the protective effects and molecular mechanisms of cordycepin against diabetes-induced testicular damage. The type 2 diabetes model was established in C57BL/6 male mice via high-fat diet for 4 weeks and injected intraperitoneally with 50 mg/kg/day streptozotocin for five consecutive days. Then mice were treated with cordycepin (10 and 20 mg/kg, respectively) for 8 weeks. At the end of experiment, biochemical indicators, microstructure of testicular tissue, sperm morphology, TUNEL staining and protein expressions were evaluated. In the present study, cordycepin alleviated the testicular damage, restored disruption of the blood-testis barrier, and improved spermatogenic function via the antiapoptotic and antioxidant capacity. Mechanistically, cordycepin significantly enhanced SIRT1 expression and triggered the activity of Foxo3a, further to induce the expression of its downstream antioxidant enzymes, including Mn-SOD and CAT. These findings indicated that cordycepin could improve hyperglycaemia-induced testicular damage by regulating downstream antioxidant enzymes activity through the SIRT1/Foxo3a signalling pathway.

Effects of Long-Term Exposure to Copper on the Keap1/Nrf2 Signaling Pathway and Msr-Related Redox Status in the Kidneys of Rats

The objective of the present study was to examine the effects of long-term exposure on oxidative damage, Keap1/Nrf2 signaling pathway, and Msr-related redox status in the kidneys of rats. Therefore, in this experimental study, a total of 32 CD-1 rats were randomized into 4 groups and treated with 30-, 60-, and 120-mg/kg Cu for 24 weeks. Different serum biomarkers suggestive of renal functions, pathological changes, and oxidative stress were analyzed in kidney tissues. Moreover, the levels of the Keap1/Nrf2 signaling pathway and redox status-related gene mRNA and proteins were also detected. The results indicated that Cu exposure dramatically increased the contents of creatinine and carbamide. Furthermore, histopathological alterations and mitochondrial damage in kidneys of rats of different Cu-treated groups were obviously observed. In addition, Cu exposure markedly changed the levels of glutathione, catalase, and total antioxidant capacity, and upregulated the contents of protein carbonyl, nitric oxide, and malondialdehyde. Moreover, higher levels of Cu treatments significantly increased the expression of Keap1/Nrf2 signaling pathway and redox status-related genes (NQO1, SOD-1, TRX, MsrA, MsrB1, MsrB2, MsrB3). Simultaneously, the mRNA expression levels of Nrf2, HO-1, and CAT were upregulated in rats exposed to 30- and 60-mg/kg Cu, but downregulated in the 120-mg/kg Cu group compared with the control group. Moreover, the Keap1/Nrf2 signaling pathway and redox status-related protein expression levels (HO-1, SOD-1, TRX, MsrA, MsrB1, MsrB2) were significantly increased in treated rats. In summary, it is suggested that the Keap1/Nrf2 signaling pathway and activation of Msr prevent Cu-induced nephrotoxicity and attenuate oxidative damage.

Metal(loid)s and human semen quality: The LIFE Study

Multiple studies have demonstrated a global population-wide decline in semen quality, with sperm concentrations having fallen 50 % over the past 50 years. Several metal and metalloid ("metal(loid)") compounds are known to have testicular toxicity, raising concerns about their contribution to rising infertility. In the male reproductive tract, metal(loid)s can reduce semen quality and disturb function both directly, by inducing tissue damage, and indirectly, by disrupting hormone production and secretion. This study assessed associations between 15 creatinine-adjusted metal(loid)s and 7 measures of semen quality among 413 reproductive-aged men recruited from 16 U.S. counties between 2005-2009. Multi-metal(loid) multivariable linear regression models estimated associations between semen quality endpoints and urinary concentrations of chromium, cobalt, copper, molybdenum, selenium, zinc, antimony, arsenic, barium, cadmium, lead, thallium, tin, tungsten, and uranium. LASSO regression was employed to select model variables and account for multicollinearity of the metal(loid)s. A positive association was observed between tin and sperm morphology (β = 4.92 p = 0.045). Chromium (β = 1.87, p = 0.003) and copper (β= -1.30, p = 0.028) were positively and negatively associated with total sperm count, respectively. With respect to DNA fragmentation, cadmium (β = 12.73, p = 0.036) was positively associated and chromium was negatively associated (β = -5.08, p = 0.001). In this cohort of U.S. population-based men, there was evidence of both positive and negative associations between specific metal(loid)s and semen quality. Additional research is needed to determine interactions between metal(loid)s within a mixture, consistent with typical human exposure, and identify sperm effects resulting from cumulative metal(loid) exposures.

Cu-induced spermatogenesis disease is related to oxidative stress-mediated germ cell apoptosis and DNA damage

Copper is considered as an indispensable trace element for living organisms. However, over-exposure to Cu can lead to adverse health effects on human. In this study, CuSO₄ decreased sperm concentration and motility, increased sperm malformation rate. Concurrently, testicular damage including testicular histopathological aberrations and reduction of testis relative weight were observed. Then, the mechanism underlying Cu-induced testicular toxicity was explored. According to the results, CuSO₄ elevated ROS production while reducing antioxidant function. Additionally, CuSO₄ induced apoptosis which was featured by MMP depolarization and up-regulated levels of cleaved-caspase-3, cleaved-caspase-8, cleaved-caspase-9, caspase-12, cleaved-PARP and Bax, whereas down-regulated Bcl-2 expression. Meanwhile, CuSO₄ caused testis DNA damage (up-regulation of γ-H2AX protein expression) and suppressed DNA repair pathways including BER, NER, HR, MMR, together with the NHEJ repair pathways, yet did not affect MGMT. To investigate the role of oxidative stress in CuSO₄-induced apoptosis and DNA damage, the antioxidant NAC was co-treated with CuSO₄. NAC attenuated CuSO₄-induced ROS production, inhibited apoptosis and DNA damage. Furthermore, the spermatogenesis disorder was also abolished in the co-treatment with CuSO₄ and NAC group. Altogether, abovementioned results indicated that CuSO₄-induced spermatogenesis disorder is related to oxidative stress-mediated DNA damage and germ cell apoptosis, impairing male reproductive function.

Mediated relationships between multiple metals exposure and fasting blood glucose by reproductive hormones in Chinese men

Previous studies have reported metals exposure contribute to the change of fasting blood glucose (FBG) level. However, the roles of reproductive hormones in their associations have not been fully elucidated. The aim of the study is to investigate the associations of multiple serum metals with reproductive hormones, and to further explore potential roles of reproductive hormones in relationships between metals exposure and FBG level. A total of 1911 Chinese Han men were analyzed by a cross-sectional study. We measured serum levels of 22 metals by inductively coupled plasma mass spectrometer (ICP-MS). FBG, total testosterone (TT), estradiol (E2), follicle stimulating hormone (FSH), and sex hormone-binding globulin (SHBG) levels were determined. Least absolute shrinkage and selection operator (LASSO) regression models were conducted to select important metals, and restricted cubic spline models were then used to estimate dose-response relationships between selected metals and reproductive hormones. We also conducted mediation analyses to evaluate whether reproductive hormones played mediating roles in the associations between metals and FBG. We found significant inverse dose-dependent trends of copper, tin and zinc with E2; zinc with SHBG; copper and nickel with TT, while significant positive dose-dependent trend of iron with E2, respectively. Moreover, approximately inverted U-shaped associations existed between lead and SHBG, iron and TT. In addition, E2, SHBG and TT were negatively associated with FBG level. In mediation analyses, the association of copper with FBG was mediated by E2 and TT, with a mediation ratio of 10.4% and 22.1%, respectively. Furthermore, E2 and SHBG mediated the relationship of zinc with FBG, with a mediation ratio of 7.8% and 14.5%, respectively. E2 mediated 11.5% of positive relationship between tin with FBG. Our study suggested that the associations of metals exposure with FBG may be mediated by reproductive hormones.

Chronic exposure to multi-metals on testicular toxicity in rats

Despite the availability of sufficient data on the effects of individual metal exposure on living organisms, a critical knowledge gap still exists in predicting effects of multi-metals particularly on the pituitary-testicular axis. Thus, the aim of the present study was to check the effects of individual or combined (binary and ternary) exposure to aluminum, copper, and zinc on (i) sperm and testosterone levels (ii) oxidative stress and (iii) structural changes in testis of male Wistar rats. Animals were exposed to aluminum, copper, and zinc either individually (20 mg/kg, orally, once, daily), binary (10 mg/kg each, orally, once daily) or in ternary combination (5 mg/kg, each, orally, once daily) for 24 weeks. The exposure to aluminum, copper individually and in combination led to a significant decrease in sperm counts and an increased oxidative stress compared to the control group. Exposure to zinc caused significant decrease in oxidative stress and an increase in different sperm variables. The exposure to zinc with aluminum or copper had no toxic effects on testis while concomitant exposure to aluminum, copper, and zinc produced more pronounced testicular injury. In summary, while co-exposure to zinc with aluminum or copper produced reproductive toxicity the co-exposure to all the three metals may lead to a significant testicular toxicity and these changes were related to increase in oxidative stress in rats.

Testicular transcriptome analysis under the dietary inclusion of l-carnitine reveals potential key genes associated with oxidative defense and the semen quality factor in aging roosters

l-carnitine (LC) has been widely studied as a natural antioxidant molecule for treating low-fertility gametes. However, the molecular mechanism of the effect of LC supplementation on the testes of aging cocks has not been evaluated. Therefore, the objective of this study was to reveal the mechanism of testicular oxidative defense induced by LC supplementation in relation to the semen quality factor (SQF) in the aging cock through a transcriptome study conducted from a new perspective. A total of 24 Jinghong cocks at 55 wk of age were randomly divided into 2 groups (n = 12). All cocks were fed a standard isocaloric and isonitrogenic breeder diet (control, LC-0), and the other group was supplemented with LC at 150 mg/kg/d (treated, LC-150) for 12 wk. Remarkably, seminal characteristics and enzymes, sex hormones, and cock fertility related to testicular oxidative defense were considerably improved by LC supplementation. LC-150 testes showed the differential upregulation and downregulation of 97 and 90 transcripts, respectively, compared with LC-0 testes. Most upregulated transcripts were involved in testicular oxidative defense and spermiogenesis optimization, whereas the downregulated genes were responsible for oxidative stress, in contrast to the SQF. Functional analysis of the transcriptionally altered genes indicated the testicular deregulation of long-chain fatty acid and lipid peroxidation, enhancing fatty acid breakdown to release ATP production via β-oxidation. These findings could lay the foundation for the discovery of new molecular markers of SQF-associated LC supplementation and potential targets for therapeutic intervention to optimize fertility in aging cocks.

L-Carnitine reduces the negative effects of formalin on sperm parameters, chromatin condensation and apoptosis in mice: An experimental study

Background

Formalin is commonly applied as an antiseptic and tissue fixative. It has reactive molecules that lead to its cytotoxic effects. According to recent studies, formalin causes a change in the testicular and sperm structure and L-carnitine (LC) acts as an antioxidant to counteract its effects.

Objective

This study aimed to investigate the protective effects of LC on the parameters, chromatin condensation and apoptosis of mice sperm exposed to formalin.

Materials and Methods

In this experimental study, 24 balb/c mice (25-40 gr,10-12 wk) were divided into three groups (n = 8/each): group I without any injections or gavage; group II, received 10 mg/ kg formalin intraperitoneally (I.P); and group III was exposed to formalin and LC, where a dose of 10 mg/kg formalin was injected I.P daily and LC the dose of 100 mg/kg was kept in a solvent solution. After 31 days, the sperm examination was performed as follows: to evaluate chromatin and DNA quality of the sperm, we applied aniline blue (AB), toluidine blue (TB), chromomycin A3 (CMA3), and terminal transferase-mediated deoxy uridine triphosphate biotin end labeling (TUNEL) tests.

Results

Sperm parameters such as count, motility, morphology, and viability displayed a significant decrease in the formalin group. While the data exhibited a considerable augment in sperm parameters in the formalin + LC than the formalin and control groups (p < 0.001), significant differences were detected between groups with respect to TB staining, TUNEL test, CMA3 test and AB staining in the formalin and formalin + LC groups.

Conclusion

LC can reduce the negative effects of formalin on sperm parameters, chromatin stability, and percentage of apoptosis in an animal model.

Integration of transcriptomic and metabolomic data reveals metabolic pathway alteration in mouse spermatogonia with the effect of copper exposure

Copper is a widespread heavy metal in environment and has toxic effects when exposed. However, study of copper-induced male reproductive toxicity is still insufficient to report, and the underlying mechanisms are unknown. Keeping in view, RNA-Seq and metabolomic were performed to identify metabolic pathways that were distressed in mouse spermatogonia with the effect of copper sulfate, and the integrated analysis of the mechanism of copper administered GC-1 cells from metabolomic and transcriptomic data. Our results demonstrated that many genes and metabolites were regulated in the copper sulfate-treated cells. The differential metabolites analysis showed that 49 and 127 metabolites were significantly different in ESI+ and ESI- mode, respectively. Meanwhile, a total of 2813 genes were up-regulated and 2488 genes were down-regulated in the treatment groups compared to those in the control groups. Interestingly, ophthalmic acid and gamma glutamylleucine were markedly increased by copper treatment in two modes. By integrating with transcriptomic and metabolomic data, we revealed that 37 and 22 most related pathways were over-enriched in ESI+ and ESI- mode, respectively. Whereas, amino acid biosynthesis and metabolism play essential role in the potential relationship between DEGs and metabolites, which suggests that amino acid biosynthesis and metabolism may be the major metabolic pathways disturbed by copper in GC-1 cells. This study provides important clues and evidence for understanding the mechanisms responsible for copper-induced male spermatogenesis toxicity, and useful biomarkers indicative of copper exposure could be discovered from present study.

Molecular machinery providing copper bioavailability for spermatozoa along the epididymial tubule in mouse

Progressive functional maturation of spermatozoa is completed during the transit of these cells through the epididymis, a tubule structure connecting a testicle to a vas deferens. Epididymal epithelial cells by means of their secretory and absorptive functions determine a highly specialized luminal microenvironment containing multiple organic and inorganic components. The latter include copper ions, which due to their redox properties are indispensable for critical homeostatic processes occurring in spermatozoa floating in different part of epididymis but can be potentially toxic. Main purpose of our study was to determine epididymal region-dependent expression and localization of copper transporters ensuring a tight control of copper concentration in epididymal fluid. We also aimed at identifying proteins responsible for copper uptake by spermatozoa and verifying whether this process is coordinated with copper supply to superoxide dismutase 1 (SOD1), a copper-dependent antioxidant enzyme. Our study identifies two ATPases-ATP7A, ATP7B and Slc31a1, major copper importers/exporters depending on their differential expression on epididymal polarized epithelial cells of the caput, corpus, and cauda. Next, ceruloplasmin seems to be a chief protein transporting copper in the epididymal fluid and providing this biometal to spermatozoa. The entry of copper to germ cells is mediated by Slc31a1 and is correlated with both expressions of copper chaperone for superoxide dismutase (CCS), copper chaperone directly providing copper ions to SOD1 and with the expression and activity of the latter. Our results outline a network of cooperating copper binding proteins expressed in epididymal epithelium and in spermatozoa that orchestrate bioavailability of this microelement for gametes and protect them against copper toxicity.

Chronic Copper Exposure Induces Hypospermatogenesis in Mice by Increasing Apoptosis Without Affecting Testosterone Secretion

Chronic copper exposure impaired spermatogenesis in adult male mice. The aim of this study was to determine whether chronic copper exposure can induce apoptosis of testicular cell and hypospermatogenesis via disturbing testosterone synthesis in adult male mice. In the present study, sixty CD-1 male mice were randomly divided into four groups, and were continuously administered for 8 weeks by oral gavage with copper sulfate at a dose of 0, 25, 100, and 150 mg/kg/day, respectively. We determined the content of serum and testicular copper, testicular coefficient, testicular histopathology, sperm count and motility, the mRNA and protein levels of Caspase-3, Bax, and Bcl-2, Leydig cell count, testosterone content, testosterone synthetase, and testosterone synthesis-related genes. The results showed that the copper levels in serum increased in a dose-dependent manner, and the copper levels in testes were significantly related to serum copper levels. Male mice given copper sulfate 100 and 150 dosage groups showed significant decreased in sperm motility and sperm number as well as increased in testes damage, and there was no significant change in testicular coefficient in the four groups. The mRNA levels of Bcl-2 decreased and Caspase-3 increased in 150 dosage group, and Bax increased in two higher dosage groups. Meanwhile, Caspase-3 and Bax proteins increased in 150 dosage group, and Bcl-2 protein decreased in three copper treatment groups. Nevertheless, there were no differences on the levels of testosterone content and testosterone synthetase of 3β-HSD, 17β-HSD, 17α-Hyd, and 20α-Hyd, mRNA levels of Cyp11a1, Cyp17a1, and Star, and quantity of Leydig cells in four groups. Overall, these data showed that chronic copper exposure led to copper residues in the testes, and the doses of 100 and 150 mg/kg/day copper sulfate may induce hypospermatogenesis by increasing apoptosis without affecting testosterone secretion.

Copper affects steroidogenesis and viability of human adrenocortical carcinoma (NCI-H295R) cell line in vitro

Copper is an environmental risk factor, which has various effects on reproductive endocrinology. In this study human adrenocortical carcinoma (NCI-H295R) cell line was used as an in vitro biological model to study the effect of copper sulfate (CuSO₄.5H₂O) on steroidogenesis and cytotoxicity. The cell cultures were exposed to different concentrations (3.90, 62.50, 250, 500, 1000 µM) of CuSO₄.5H₂O and compared to control group (medium without CuSO₄.5H₂O). Cell viability was measured by the metabolic activity assay. Quantification of sexual steroid production directly from the medium was performed by ELISA assay. Following 48 h culture of NCI-H295R cell line in the presence of CuSO₄.5H₂O a dose-dependent depletion of progesterone release was observed even at the lower concentrations of CuSO₄.5H₂O. The lowest levels of progesterone were detected in groups with the higher doses (≥ 250 µM) of CuSO₄.5H₂O, which elicited significant cytotoxic action. Testosterone production decreased significantly, and this decline was more prominent in comparison to that of progesterone. The lowest release of testosterone was recorded at 1000 µM of CuSO₄.5H₂O. The cytotoxic effect of CuSO₄.5H₂O was evident at all concentrations used in the study. The presented data suggest that copper has detrimental effects on sexual steroid hormones and consecutively on reproductive physiology.

Bee glue (propolis) improves reproductive organs, sperm quality and histological changes and antioxidant parameters of testis tissues in rats exposed to excess copper

This study was designed to determine the effects of propolis on the sperm quality, antioxidant and histological parameters in the testicular tissues of male Sprague Dawley rats exposed to excessive copper (Cu). In this aim, 24 rats were randomly divided into four groups as follows: the control, Cu, Propolis and Cu+Propolis. When compared to control group, Cu administration significantly decreased sperm motility and concentration, increased total abnormal sperm rate. It caused a significant induction the malondialdehyde (MDA), and reduction the superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) in testicular tissues. Also, it caused loss, disorganisation and vacuolation of the germinal epithelium, oedema of the interstitial tissues, proliferation of the interstitial cells, spilled immature spermatogenic cells in the lumen of some seminiferous tubules. A large number of active caspase-3-positive stained apoptotic cells and a significant decrease in Johnsen's testicular score were determined. However, significant ameliorations were observed in all sperm characteristics, MDA, SOD, CAT, GSH, seminiferous tubules, number of apoptotic cells and Johnsen's testicular score in Cu+Propolis group. Our results showed that oral supplementation of propolis had curative effect on the sperm quality, antioxidant and histological parameters in the testicular tissues of male Sprague Dawley rats exposed to Cu.

Effectiveness and Safety Evaluation of Qixiong Zhongzi Decoction () in Idiopathic Asthenozoospermia Treatment: A Randomized Controlled Trial

OBJECTIVE

To evaluate the clinical effectiveness and safety of the Chinese medicine (CM) Qixiong Zhongzi Decoction (, QZD) in the treatment of patients with idiopathic asthenozoospermia.

METHODS

A total number of 66 patients with idiopathic asthenozoospermia were included and randomly divided into treatment and control groups by SAS-generated code from January 2015 to August 2016, 33 patients in each group. Patients in the treatment group were administered with 150 mL of QZD twice a day, whereas those in the control group were given 1 g of levocarnitine oral liquid twice a day. The two groups received the indicated medication for 12 weeks and were then followed up for 4 weeks. The primary outcome was sperm motility, and the secondary therapeutic indices were sperm volume, density, pregnancy probability, and CM syndrome score. The comparison between groups was carried out at 4, 8 and 12 weeks, respectively. The safety was determined before and after treatment.

RESULTS

(1) Drop-off: 5 cases (7.58%) were lost after treatment (2 from the treatment group and 3 from the control group). (2) Primary outcomes: after 8- and 12-week treatment, the progressive sperms in the two groups were significantly higher than the baseline (all P<0.05); however, the treatment group showed greater improvement compared with the control group at 12-week treatment (22.7% ± 9.0% vs. 14.1% ±8.8%, P<0.05). The increasement of non-progressive grade sperms at both groups was observed at 8- and 12-week treatment with statistical difference (all P<0.05), however, the treatment group showed remarkable improvement compared with the control group at 12-week treatment (38.7% ±14.1% vs. 26.2% ±15.4%, P<0.05). (3) Secondary outcomes: no significant statistical differences were found in semen volume and density (4, 8, and 12-week treatment) and pregnancy probability of patients' wives (12-week treatment) between two groups (all P>0.05), however, the CM syndrome score of the treatment group significantly declined compared with baseline level at each time points (all P<0.05). (4) Safety: no obvious side reactions were found during the treatment in both groups.

CONCLUSION

QZD could improve the progressive and non-progressive grade sperm in the treatment of idiopathic asthenozoospermia. It is safe with no obvious side effects.

Effect of chronic L-carnitine supplementation on carnitine levels, oxidative stress and apoptotic markers in peripheral organs of adult Wistar rats

This study investigated the effects of L-carnitine supplementation on carnitine levels, oxidative stress and apoptotic markers in the stomach, kidney, liver and testis tissues in adult rats. Rats were randomized to control and L-carnitine supplemented (LCAR) groups. Control group received distilled water for 7 months by intragastric gavage and the LCAR group was given 50 mg/kg/day L-carnitine via intragastric intubation for the same period. L-carnitine concentrations and caspase-3 activity were measured by fluorometric methods while cleaved caspase-3 was determined by Western blot analysis. Bcl-2 associated X protein (Bax) and B-cell lymphoma/leukemia-2 (Bcl-2) were quantified by enzyme immunoassay and Western blot analysis. Oxygen/nitrogen species (ROS/RNS) and total antioxidant capacity (TAC) were analyzed by colorimetric assay. Tissue L-carnitine concentrations were significantly increased in the LCAR group compared to controls. Anti-apoptotic Bcl-2 levels were significantly increased while pro-apoptotic Bax was significantly decreased in LCAR group rats compared to controls. Tissue caspase-3 was significantly alleviated in the LCAR group compared to controls. L-carnitine supplementation increased TAC and decreased ROS/RNS generation in the kidney, liver, stomach and testis tissues compared to controls. Obtained data suggests that L-carnitine supplementation can potentially be used to lessen both oxidative and apoptotic progression in peripheral organs.

Protective effects of tribulus terrestris extract and angiotensin blockers on testis steroidogenesis in copper overloaded rats

The rational of the current study was to assess whether Tribulus terrestris extract (TTE) could alleviate long-term copper (Cu) overload-induced testicular dysfunction compared to enalapril and losartan. Rats were administered either vehicle (control group, n = 10) or copper sulfate pentahydrate (CuSO₄·5H₂O, 200 mg/kg, p.o) for 90 days (n = 40). Cu-treated rats were randomized into four equal groups. One group was left untreated (Cu group) while the remaining three groups were daily co-treated with one of the following treatments along with CuSO4: TTE (10 mg/kg, p.o); enalapril (30 mg/kg, p.o); losartan (10 mg/kg, p.o). Excess Cu intake resulted in Cu overload coupled with a significant elevation in systolic blood pressure and serum angiotensin II levels along with a reduction in serum nitric oxide level. All concomitant treatments led to an alleviation of such deleterious effects. However, only losartan failed to ameliorate angiotensin II elevation. Additionally, all treatments protected the testes against Cu-overload-elicited zinc depletion and oxidative stress. Regarding reproductive function, the relative weights of testes, serum levels of testosterone and luteinizing hormone; the expression of steroidogenic genes; the protein levels of angiotensin II type 1 receptor and angiotensin converting enzyme 1, in addition to its activity, they were significantly reduced. Amongst all treatments, only TTE and E were able to revert these reproductive changes. In conclusion TTE and E were able to protect against Cu overload-induced impairment of testicular steroidogenesis. Thus, they might be considered as prophylactic drugs of choice against hypertension and testicular dysfunction to ameliorate Cu overload risk.

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 Resveratrol Alleviates the Hepatic Toxicity of CuSO4 in the Rat

Cu is toxic to humans and other animals. Oxidative stress is an important mechanism involved in Cu toxicity. Resveratrol (RSV) is an antioxidative compound, so could counteract Cu toxicity. The aim of this study was to determine whether RSV protects the liver from the effects of CuSO₄. Forty male Sprague-Dawley rats (5 weeks old, 110-120 g) were divided into four groups (n = 10 per group), a control group and groups treated with CuSO₄ at a dose of 200 mg/kg body weight (BW), RSV at a dose of 15 mg/kg BW, and CuSO₄ at a dose of 200 mg/kg BW and RSV at a dose of 15 mg/kg BW. The treatments were orally administered for 30 days. The livers were removed from the rats at the end of the study, and the cytochrome P450, cytochrome b5, Cu, Fe, Zn, glutathione peroxidase, superoxide dismutase, reactive oxygen species, aspartate aminotransferase, and alanine aminotransferase concentrations in the livers were determined. CuSO₄ decreased the BW, liver weight, and cytochrome P450, cytochrome b5, Fe, Zn, glutathione peroxidase, and superoxide dismutase concentrations but increased the Cu, aspartate aminotransferase, alanine aminotransferase, and reactive oxygen species concentrations relative to the control group. RSV alleviated the toxic effects of CuSO₄ on the liver, indicating that RSV attenuates CuSO₄-induced liver injury by decreasing the liver transaminase concentration and oxidative stress, promoting antioxidative activity and cytochrome P450 enzymes, and maintaining balance in the trace element concentrations. The results indicate that RSV could be used to treat CuSO₄ toxicity.

Oxidative damage induced by copper in testis of the red swamp crayfish Procambarus clarkii and its underlying mechanisms

Copper (Cu) is one of the most widespread environmental pollutants and is known to exert multiple toxic effects including reproductive toxicity. In this study, we investigated the toxic effect of Cu on reproduction of the red swamp crayfish (Procambarus clarkii), an economic crustacean species, by exposing adult male crayfish to 0.03 and 3.00 mg/L Cu²⁺ for 7 days. The results showed that Cu²⁺ exposure induced oxidative stress accompanied by elevated reactive oxygen species (ROS) and malondialdehyde (MDA) levels in testes, and resulted in decreased sperm quality and abnormal testicular structures with apoptotic germ cells and vacuolisation in Sertoli cells. To reveal the molecular mechanism of Cu²⁺-induced oxidative damage in crayfish testes, we sequenced, assembled and annotated the transcriptome for crayfish testes, using the Illumina sequencing approach. After the 3.00 mg/L Cu²⁺ treatment, 6745 genes with differentially expressed profile were identified, of which many genes were involved in cellular response to ROS based on Gene Ontology enrichment analysis. Further, KEGG analysis demonstrated that genes with up-regulated expression levels significantly enriched in mitochondria oxidative phosphorylation pathway, suggesting disturbed mitochondrial electron transport chain was probably a main source of Cu²⁺-induced ROS production in testes. This study represented the first use of transcriptome to investigate the toxic effect of Cu²⁺ on male crayfish reproduction, and the pathways identified underlying Cu²⁺ toxicity at molecular level provide a novel insight into the reproductive toxicity of Cu in crustaceans.

l-arginine protects against T-2 toxin-induced male reproductive impairments in mice

l-arginine is beneficial for reproductive health; however, whether l-arginine may confer protection against T-2 toxin-induced reproductive impairment is not known. To address this, we used a mice model treated with T-2 toxin to investigate protective effects of l-arginine. Experimentally, we pre-treated mice with designed diet of l-arginine supplementation prior to the T-2 toxin-injected intraperitoneally exposure and then assessed semen quality, fertility and serum testosterone concentration. The results showed that l-arginine improved semen quality (e.g., live spermatozoa, abnormal spermatozoa, and acrosomal integrity of spermatozoa), testicular and cauda epididymal sperm counts, efficiency of sperm production and serum testosterone concentration in mice treated with T-2 toxin. In addition, l-arginine could increase pregnancy rate and decrease fetal resorption rate in females mated with T-2 toxin exposed males. Collectively, these findings suggest that dietary l-arginine supplementation may protect male reproductive impairments in mice treated with T-2 toxin through improving semen quality and serum testosterone levels.

Effects of L-Carnitine on the sperm parameters disorders, apoptosis of spermatogenic cells and testis histopathology in diabetic Rats

Background

Diabetes mellitus affects male reproductive system that is known to cause male infertility.

Objective

The aim of the present study was to assess the effects of L-carnitine (LC) on sperm parameters, apoptosis of spermatogenic cells and testis histopathology in Streptozotocin-induced diabetic Rats.

Materials and Methods

The study was carried out on 36 male Wistar adult rats (220 ± 30 gr) randomly divided into six groups (n = 6/each). 1 (Control); 2 (LC 100 mg/kg); 3 (Diabetic); 4, 5, and 6 (Diabetic + LC 50 or 100 or 200 mg/kg, respectively). Daily injections were administered intraperitoneally for 48 days. Then, rats were sacrificed, left testis and epididymis were harvested for sperm analysis and histopathology, morphometric and spermatogenesis assessments, and Tunnel assay.

Results

L-carnitine in group 6 significantly decreased blood glucose level (p < 0.01) in comparison with group 3. L-carnitine in groups 5 and 6 significantly (p < 0.001) and dose-dependently increased the count, motility, viability, maturity, and chromatin quality of sperm and decreased the abnormal morphology of sperm in comparison with group 3. In groups 4, 5, and particularly 6, in comparison with group 3, there has been a significant difference in the increase of seminiferous tubule diameter, germinal epithelium height (p < 0.001), maturity quality of the seminiferous tubules (p < 0.001), decrease apoptosis of spermatogenic cells (p < 0.001), and testis tissue histopathological complications.

Conclusion

The data obtained from the present study suggest that in the diabetic rats, LC decreases serum glucose level, improves the diameter and thickness of the epithelium of spermatogenic cells, reduces germ cells' apoptosis, and improves epididymal sperm parameters. Therefore, it seems that LC plays an effective role in diabetes-induced infertility.