Calcium channels play essential roles in sperm motility. A family of sperm-specific cation channels including CatSper1–4 has been identified as voltage-dependent ion channels that act as sperm motility regulators. Methamphetamine is known to cause apoptosis in seminiferous tubules and affect sperm quality. This research was conducted to investigate the effects of methamphetamine on expression of the CatSper family and Mvh genes. Thirty-six adult Wistar rats were divided into four groups of nine rats each: the control and experimental groups 1, 2, and 3. The control group received no solvents or drugs, but experimental groups 1, 2, and 3 were daily given 0.2 mL of a solution by gavage that contained 0.5, 1, and 2 mg of methamphetamine, respectively, for 45 days. The rats were then anesthetized, and one testis removed from each rat was used in a reverse transcription-polymerase chain reaction (RT-PCR). Analysis of variance (ANOVA) and Tukey’s posthoc test were used to analyze the data at the P < 0.05 significance level. Treatment with methamphetamine resulted in decreased testis and epididymis weights compared to the control rats. The results showed that the mRNA fold expression level of the CatSper family and Mvh genes decreased significantly in experimental groups compared to that in the control (P < 0.05). Methamphetamine decreased the expression levels of the CatSper and Mvh genes, and thus, it seemed that it can increase the probability of infertility through sperm motility reduction by lowering the expression levels of these genes.

Study question Does quercetin (75 or 100 mg/kg BW/day) co-administration with lead acetate to male mice affects embryonic development in female mice? Summary answer The low-dose quercetin (75 mg/kg BW/day) ameliorated the adverse effects of lead acetate on mouse embryogenesis. What is known already Lead causes male infertility by impacting on endocrine system and spermatogenesis, and may exert undesirable effects on the offspring. The currently approved treatment for lead poisoning is the use of chelating agents, which form an insoluble complex with lead and shield it from biological targets; thus, reducing its toxicity. One of the main mechanisms of lead-induced toxicity is oxidative stress, and it has been reported that natural antioxidants can reduce the heavy metals toxicity. The aim of the present study was to examine the protective effects of quercetin on the toxicity induced by lead acetate on the embryogenesis in mice. Study design, size, duration Sexually mature (eight-week-old) NMRI male mice (n = 24) were randomly divided into four groups (n = 6 per group) receiving (i) distilled water (control group); (ii) lead acetate (150 mg/kg BW/day) dissolved in deionized water (LA); (iii) lead acetate (150 mg/kg BW/day) + quercetin (75 mg/kg BW/day) (LQ75); (IV) lead acetate (150 mg/kg BW/day) + quercetin (100 mg/kg BW/day) (LQ100). Treatments were applied daily as oral gavages for one cycle of the seminiferous epithelium (35 days). Participants/materials, setting, methods At the end of treatment administration, the males were joined with super-ovulated females, and the retrieved zygotes were cultured for evaluation of the embryo development (at 2-cell, 4-cell, 8-cell, and blastocyst stages), and blastocyst cell number using differential staining (propidium iodide and bisbenzimide). After incubation of capacitated sperm with oocytes, an ultraviolet light microscope was used following 3 min incubation with 25 µg⁄mL bisbenzamide solution for fertilization assessment. Main results and the role of chance Lead acetate (LA) treatment of male mice decreased the 2-cell stage compared with the control group (P &gt; 0.05). There was no difference between control and LQ75, and between LA and LQ100. The other stages of embryonic development were not significantly affected by the treatment. Overall, early embryonic development in the control and LQ75 mice were better than LQ100 and LA mice. The number of cells in the trophectoderm and inner-cell mass were not affected by treatments. However, the total blastocyst cell number in the control was higher than in the other groups; there was no significant difference between LQ100, LQ75 and LA groups. Fertilization rate was not affected by the treatments (P &lt; 0.05). Quercetin acts as a potent antioxidant at low doses, but at high doses exerts a pro-oxidant action. According to previous reports, higher concentrations of quercetin increased apoptosis and necrosis while decreasing the activities of the antioxidant enzymes. Also, it has been suggested that quercetin might disrupt the endocrine system and interfere with Sertoli cell function and sperm motility. Limitations, reasons for caution A limitation of this study is narrow dose selection; more studies are needed to determine the effective dose of quercetin in ameliorating the lead toxicity. There are also side effects of lead-quercetin chelates such as metal redistribution, essential metal loss, accumulation and persistency in intracellular sites, and peroxidation. Wider implications of the findings: Lead administration adversely impacted on the embryogenesis; on the other hand, paternal quercetin co-administration somewhat ameliorated the adverse effects of lead on mice embryogenesis. Trial registration number Not applicable