Antioxidant protects blood-testis barrier against synchrotron radiation X-ray-induced disruption

L-Cysteine Upregulates Testosterone Biosynthesis and Blood-Testis Barrier Genes in Cultured Human Leydig Cells and THP-1 Monocytes and Increases Testosterone Secretion in Human Leydig Cells

Leydig cells are the primary source of testosterone or androgen production in male mammals. The blood-testis barrier (BTB) maintains structural integrity and safeguards germ cells from harmful substances by blocking their entry into the seminiferous tubules. L-cysteine is essential to the production of glutathione, a powerful antioxidant crucial to protecting against oxidative stress-induced damage. Animal studies have demonstrated the protective effect of L-cysteine in preventing testicular damage caused by chemicals or radiation. This study examines whether L-cysteine enhances the expression of testosterone biosynthesis and the BTB genes in human Leydig cells and THP-1 monocytes. The Leydig cells and THP-1 monocytes were treated with L-cysteine for 24 h. RNA was extracted following treatment, and the gene expression was analyzed using quantitative RT-PCR. Testosterone levels in the cell supernatant were measured using an ELISA kit. L-cysteine treatment in Leydig cells significantly upregulated the expression of CYP11A1 (p = 0.03) and the BTB genes CLDN1 (p = 0.03), CLDN11 (p = 0.02), and TJP1 (p = 0.02). Similarly, L-cysteine significantly upregulated the expression of CYP11A1 (p = 0.03) and CYP19A1 (p < 0.01), and the BTB genes CLDN1 (p = 0.04), CLDN2 (p < 0.01), CLDN4 (p < 0.01), CLDN11 (p < 0.01), and TJP1 (p = 0.03) in THP-1 monocytes. Further, L-cysteine supplementation increased the testosterone secretion levels in human Leydig cells. The findings suggest that L-cysteine supplementation could be used as an adjuvant therapy to promote the integrity of the BTB genes, testosterone biosynthesis and secretion, and the maintenance of testicular functions, which in turn mitigates the risk of male infertility.

The Protective Role of L-Cysteine in the Regulation of Blood-Testis Barrier Functions-A Brief Review

Blood-testis barrier (BTB) genes are crucial for the cellular mechanisms of spermatogenesis as they protect against detrimental cytotoxic agents, chemicals, and pathogens, thereby maintaining a sterile environment necessary for sperm development. BTB proteins predominantly consist of extensive tight and gap junctions formed between Sertoli cells. These junctions form a crucial immunological barrier restricting the intercellular movement of substances and molecules within the adluminal compartment. Epithelial tight junctions are complex membrane structures composed of various integral membrane proteins, including claudins, zonula occludens-1, and occludin. Inter-testicular cell junction proteins undergo a constant process of degradation and renewal. In addition, the downregulation of genes crucial to the development and preservation of cell junctions could disrupt the functionality of the BTB, potentially leading to male infertility. Oxidative stress and inflammation may contribute to disrupted spermatogenesis, resulting in male infertility. L-cysteine is a precursor to glutathione, a crucial antioxidant that helps mitigate damage and inflammation resulting from oxidative stress. Preclinical research indicates that L-cysteine may offer protective benefits against testicular injury and promote the expression of BTB genes. This review emphasizes various BTB genes essential for preserving its structural integrity and facilitating spermatogenesis and male fertility. Furthermore, it consolidates various research findings suggesting that L-cysteine may promote the expression of BTB-associated genes, thereby aiding in the maintenance of testicular functions.

The Impact of Vitamin D and L-Cysteine Co-Supplementation on Upregulating Glutathione and Vitamin D-Metabolizing Genes and in the Treatment of Circulating 25-Hydroxy Vitamin D Deficiency

Vitamin D receptors are expressed in many organs and tissues, which suggests that vitamin D (VD) affects physiological functions beyond its role in maintaining bone health. Deficiency or inadequacy of 25(OH)VD is widespread globally. Population studies demonstrate that a positive association exists between a high incidence of VD deficiency and a high incidence of chronic diseases, including dementia, diabetes, and heart disease. However, many subjects have difficulty achieving the required circulating levels of 25(OH)VD even after high-dose VD supplementation, and randomized controlled clinical trials have reported limited therapeutic success post-VD supplementation. Thus, there is a discordance between the benefits of VD supplementation and the prevention of chronic diseases in those with VD deficiency. Why this dissociation exists is currently under debate and is of significant public interest. This review discusses the downregulation of VD-metabolizing genes needed to convert consumed VD into 25(OH)VD to enable its metabolic action exhibited by subjects with metabolic syndrome, obesity, and other chronic diseases. Research findings indicate a positive correlation between the levels of 25(OH)VD and glutathione (GSH) in both healthy and diabetic individuals. Cell culture and animal experiments reveal a novel mechanism through which the status of GSH can positively impact the expression of VD metabolism genes. This review highlights that for better success, VD deficiency needs to be corrected at multiple levels: (i) VD supplements and/or VD-rich foods need to be consumed to provide adequate VD, and (ii) the body needs to be able to upregulate VD-metabolizing genes to convert VD into 25(OH)VD and then to 1,25(OH)2VD to enhance its metabolic action. This review outlines the association between 25(OH)VD deficiency/inadequacy and decreased GSH levels, highlighting the positive impact of combined VD+LC supplementation on upregulating GSH, VD-metabolizing genes, and VDR. These effects have the potential to enhance 25(OH)VD levels and its therapeutic efficacy.

Beneficial role of naringin against methotrexate-induced injury to rat testes: biochemical and ultrastructural analyses

Background

Methotrexate (MTX) is a commonly used chemotherapeutic drug that has adverse toxic effects on germ cells. Naringin (NG) is a natural flavanone glycoside, with different phytotherapeutic applications, and its possible protective effects against MTX-induced testicular tissue damage were investigated in this study.

Methods

Low and high doses of NG (40 and 80 mg/kg/day) were given for 10 days by intraperitoneal (i.p.) injection and MTX (20 mg/kg i.p.) was given at the 4th day of the experiment, with or without NG in rats.

Results

The obtained results showed that exposure to MTX increased malondialdehyde (MDA) levels and nitric oxide (NO) production compared with the control. In the meantime, MTX depleted catalse (CAT), superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GPx), and reduced glutathione (GSH) in the testicular tissue. Further, serum testosterone levels were significantly decreased in the MTX group. NG significantly counteracted the aforementioned effects of MTX; however, NG80 was more effective in restoring SOD, GR, MDA and NO. Interestingly, NG80 achieved a better improvement in the ultrastructural pattern of the testicular cells in MTX-exposed rats.

Conclusion

These results indicated, for the first time, that NG could be a potential candidate therapy against MTX-reprotoxic impacts.

Evaluating the protective effect of resveratrol, Q10, and alpha-lipoic acid on radiation-induced mice spermatogenesis injury: A histopathological study

Background

Testis is one of the most sensitive organs against the toxic effect of ionizing radiation. Exposure to even a low dose of radiation during radiotherapy, diagnostic radiology, or a radiological event could pose a threat to spermatogenesis. This may lead to temporary or permanent infertility or even transfer of genomic instability to the next generations.

Objective

In this study, we evaluated the protective effect of treatment with three natural antioxidants; resveratrol, alpha lipoic acid, and coenzyme Q10 on radiation-induced spermatogenesis injury.

Materials and Methods

30 NMRI mice (6-8 wk, 30 ± 5 gr) were randomly divided into six groups (n = 5/each) as 1) control; 2) radiation; 3) radiation + resveratrol; 4) radiation + alpha lipoic acid; 5) radiation + resveratrol + alpha lipoic acid; and 6) radiation+ Q10. Mice were treated with 100 mg/kg resveratrol or 200 mg/kg alpha lipoic acid or a combination of these drugs. Also, Q10 was administered at 200 mg/kg. All treatments were performed daily from two days before to 30 min before irradiation. Afterward, mice were exposed to 2 Gy 60 Co gamma rays; 37 days after irradiation, the testicular samples were collected and evaluated for histopathological parameters.

Results

Results showed that these agents are able to alleviate some toxicological parameters such as basal lamina and epididymis decreased sperm density. Also, all agents were able to increase Johnsen score. However, they could not protect against radiation-induced edema, atrophy of seminiferous tubules, and hyperplasia in Leydig cells.

Conclusion

This study indicates that resveratrol, alpha-lipoic acid, and Q10 have the potential to reduce some of the side effects of radiation on mice spermatogenesis. However, they cannot protect Leydig cells as a source of testosterone and seminiferous tubules as the location of sperm maturation.

Effects of Chemotherapy and Radiotherapy on Spermatogenesis: The Role of Testicular Immunology

Substantial improvements in cancer treatment have resulted in longer survival and increased quality of life in cancer survivors with minimized long-term toxicity. However, infertility and gonadal dysfunction continue to be recognized as adverse effects of anticancer therapy. In particular, alkylating agents and irradiation induce testicular damage that results in prolonged azoospermia. Although damage to and recovery of spermatogenesis after cancer treatment have been extensively studied, there is little information regarding the role of differences in testicular immunology in cancer treatment-induced male infertility. In this review, we briefly summarize available rodent and human data on immunological differences in chemotherapy or radiotherapy.