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.

Strontium Chloride Improves Reproductive Function and Alters Gut Microbiota in Male Rats

Strontium (Sr) is an essential trace element in the human body and plays an important role in regulating male reproductive health. Recent studies have shown that gut flora plays a key role in maintaining spermatogenesis, as well as testicular health, through the gut-testis axis. At present, it is unclear whether gut microbiota can mediate the effects of Sr on sperm quality, and what the underlying mechanisms may be. We investigated the effects of different concentrations of strontium chloride (SrCl2) solutions (0, 50, 100, and 200 mg/kg BW) on reproductive function and gut microbiota in male Wistar rats (6-8 weeks, 250 ± 20 g). All the animals were euthanized after 37 days of treatment. The Sr-50 group significantly increased sperm concentration, sperm motility, and sperm viability in rats. After Sr treatment, serum and testicular testosterone (T) and Sr levels increased in a dose-dependent manner with increasing Sr concentration. At the same time, we also found that testicular marker enzymes (ACP, LDH) and testosterone marker genes (StAR, 3β-HSD, and Cyp11a1) increased significantly in varying degrees after Sr treatment, while serum NO levels decreased significantly in a dose-dependent manner. Further investigation of intestinal flora showed that SrCl2 affected the composition of gut microbiome, but did not affect the richness and diversity of gut microbiota. Sr treatment reduced the number of bacteria with negative effects on reproductive health, such as Bacteroidetes, Tenericutes, Romboutsia, Ruminococcaceae_UCG_014, Weissella, and Eubacterium_coprostanoligenes_group, and added bacteria with negative effects on reproductive health, such as Jeotgalicoccus. To further explore the Sr and the relationship between the gut microbiota, we conducted a Spearman correlation analysis, and the results showed that the gut microbiota was closely correlated with Sr content in serum and testicular tissue, sex hormone levels, and testicular marker enzymes. Additionally, gut microbiota can also regulate each other and jointly maintain the homeostasis of the body's internal environment. However, we found no significant correlation between intestinal flora and sperm quality in this study, which may be related to the small sample size of our 16S rDNA sequencing. In conclusion, the Sr-50 group significantly increased T levels and sperm quality, and improved the levels of testicular marker enzymes and testosterone marker genes in the rats. Sr treatment altered the gut flora of the rats. However, further analysis of the effects of gut microbiota in mediating the effects of SrCl2 on male reproductive function is needed. This study may improve the current understanding of the interaction between Sr, reproductive health, and gut microbiota, providing evidence for the development of Sr-rich foods and the prevention of male fertility decline.

Qiangjing tablets repair of blood-testis barrier dysfunction in rats via regulating oxidative stress and p38 MAPK pathway

Background

The blood-testis barrier (BTB) is a physical barrier of the testis to prevent various exogenous substrates from entering apical compartments and provides immune privilege for spermatogenesis, which is essential for normal spermatogenic function of testis. It has been shown that oxidative stress can damage BTB by activating the p38 MAPK pathway. In Traditional Chinese Medicine, Qiangjing tablets (QJT) improve spermatogenesis and increase pregnancy rates. Previous studies have confirmed that QJT can improve sperm quality and have obvious antioxidant effects. In this study, we explore whether QJT contributes to recovery from BTB dysfunction in rats.

Methods

BTB dysfunction was induced in rats by 1% Cyclophosphamide (CP). The CP-induced rats in the treatment group were given a dose of QJT (0.45 g/kg·d) by gavage. Testis tissues were collected for histopathological and biochemical analysis, and the testis weight was estimated. Levels of BTB-related proteins and antioxidant enzyme were analyzed in the testis tissues.

Results

QJT resolved the pathological injury of rats testis induced by CP. Furthermore, MDA levels were significantly reduced, and the levels of SOD markedly increased in the testicular tissue after QJT treatment. In addition, QJT down-regulated the expression of p38 protein in rat testis and up-regulated the expressions of key proteins ZO-1, occludin and F-actin in BTB.

Conclusion

These results demonstrate that QJT exerts protective effects on CP-induced rats with BTB dysfunction, likely by regulating the oxidative stress-mediated p38 MAPK pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03615-z.

Protective effect of gallic acid on apoptosis of sperm and in vitro fertilization in adult male mice treated with cyclophosphamide

BACKGROUND

Alteration of free radicals (reactive oxygen species) causes mammals' sperm damage. Gallic acid (GA) is known as an antioxidant which is effective against oxidative stress. The purpose of this study was to evaluate the antioxidant effects of GA on the sperm apoptosis and in vitro fertilization (IVF) in adult male mice treated with cyclophosphamide (CP).

MATERIALS AND METHODS

Following a pilot study to find the dose responses of GA, 40 adult male naval medical research institute (NMRI) mice (32 ± 3 g) were divided into five groups (n = 8): control, sham (normal saline, NS: 0.2 mL per day), CP (15 mg kg^-1 per week; intraperitoneal, IP), GA (12.5 mg kg ^-1 per day; IP), and GA+CP. After the treatment, sperm parameters were analyzed. The apoptosis of sperm was measured by Annexin-PI staining method followed by flow cytometry detection. Fertility was assessed by IVF method among the groups.

RESULTS

The difference in sperm parameter and fertility rate between the control (% 80.05 ± 6.53) and cyclophosphomide groups (% 51.82 ± 10.78) was significant (P < .001) but GA plus CP (% 78.16 ± 5.71) restored the fertilization rate (P < .001). Also, a remarkable increase was noted regarding apoptotic sperm in CP group vs the control group. The comparison in the five groups shows that GA cotreatment was significantly effective in reducing the apoptosis rate caused by cyclophosphamide (P < .05).

CONCLUSION

It was ultimately attained that GA has a potent antioxidant effect which could inhibit the detrimental effect of CP on the apoptosis and fertility rate of sperm in the mouse.

Overexpression of microRNA-204-5p alleviates renal ischemia-reperfusion injury in mice through blockage of Fas/FasL pathway

The multiple roles of microRNA-204-5p (miR-204-5p) in numerous types of cancer have been reported, but its function in renal ischemia-reperfusion injury (RIRI) remains unclear. In this study, we aim to explore whether miR-204-5p was implicated in the RIRI in mice via regulating the Fas/Fas ligand (FasL) pathway. Firstly, the Gene Expression Omnibus (GEO) database was used to screen RIRI-related differentially expressed genes (DEGs). Then, RIRI mouse model was established, and the role of miR-204-5p and FasL in RIRI was explored by ectopic expression, depletion and reporter assay experiments. The blood urea nitrogen (BUN) and serum creatinine (Scr) levels in serum, as well as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) in renal tissues of mice were also measured. Afterwards, the regulatory role of miR-204-5p on Fas/FasL pathway in RIRI was investigated. Renal tissues from RIRI mice showed lower miR-204-5p expression and higher Fas and FasL expression. FasL was identified as a direct target gene of miR-204-5p. In addition, the increased levels of BUN, Scr and MDA, as well as decreased levels of SOD and GSH-Px in RIRI mice were reversed by elevation of miR-204-5p and blockage of the Fas/FasL pathway. Taken together, this study demonstrated that increased miR-204-5p might suppress RIRI in mice through suppressing Fas/FasL pathway by targeting FasL.

The mechanisms of cyclophosphamide-induced testicular toxicity and the protective agents

INTRODUCTION

Cyclophosphamide (CP) is an alkylating antineoplastic agent with known toxicity to the male reproductive system. Areas covered: This review summarizes the known mechanisms by which CP exerts its toxic effects on the male reproductive system and the methods utilized to prevent such effects so that it could be further investigated and applied in clinical use. Keywords including ['Cyclophosphamide' AND 'male reproductive' OR' sperm toxicity' OR 'spermatotoxicity' OR 'infertility] were searched through Google Scholar, PubMed and Scopus databases based on PRISMA guidelines. After removing duplicates and irrelevant data, 76 papers were reviewed concerning the outcomes of treatment of male mice, rats, and humans with CP and the effects of co-administration of various natural and synthetic compounds on male reproductive system. Expert opinion: CP exerts its effect mainly by inducing oxidative stress and changing gene expression in spermatocytes variably during different stages of development. These effects could be either restored or prevented by the administration of compounds with antioxidant properties and those which target the biochemical alterations induced by CP.