In our previous study, we have shown that sperm parameters in aging mice decreased, compared to those of the young adult mice [
15]. Many mechanisms have been suggested to explain the effects of aging on sperm quality [
14]. For example, in the aging subjects, smooth muscle atrophy in the prostate and a decrease in its protein and water content may affect semen volume and sperm motility. Sperm acquires capacitation when it passes through the epididymis, where it plays an important role in sperm maturation. Sperm motility decreases during aging because of suppression in epididymal function. Sperm morphology is a good index for the status of the germinal epithelium. Aging causes degenerative alterations in the germinal epithelium and may affect spermatogenesis and alter sperm morphology [
14].
CatSper genes expression in mouse testis was detected as early as 3 weeks of age by Nikpoor et al [
4]. In the present study,
CatSper gene family was also expressed in the 2-3 months old young adult and the 11-13 months old aging male mice and no significant decrease was detected in the expression of
CatSper genes between the two groups. A novel finding of our study is that Se administration caused up-regulation in
CatSper genes family. However, Se treatment in the 11-13 months old aging male mice caused more up-regulation compared to the young adult ones, suggesting that the Se treatment had a more profound effect on
CatSper expression in the aging male mice. At the same time, spermatogenesis was improved in the aging subjects treated with Se. It seems that there is a correlation between Se treatment and improvement of sperm quality. Noting that
CatSper1 gene expression changes were more than those of the other
CatSper family members, most likely this gene has a more strong regulatory effect (at least for Se). However, the expression of
CatSper1 was not changed with an increase in age. Furthermore, we observed a significant up-regulation of
CatSper1 gene expression on the day 21 in the aging male mice, showing that short-time Se treatment was effective. The relative intensity of
CatSper genes expression in the aging mice was more than that in the young adult mice on the days 21 and 28, and the ratio in the adult mice was more than that in the aging mice on the days 35 and 42. However, further molecular studies are needed to confirm our finding. Regulation of
CatSper genes factors and the effects of antioxidants on their expression have not been reported thus far. Some studies have demonstrated that antioxidants could affect gene expression. Gan et al [
16]. observed that GSH-PX mRNA levels remarkably increased in the rats testis injected with 0.02 mg/kg/d Se. However, injection of 0.04 and 0.08 mg/kg Se dramatically decreased GSH-PX expression, in comparison to the 0.02 mg/kg group. In another study, Jervis et al. reported that vitamin E treatment affected the expression of oxidative stress-related genes in the aging male rats. Moreover, vitamin E deficiency causes the accumulation of oxidative stress damage in the epididymis of aging rats [
9]. A recent study has demonstrated that changes in the Se level leads to a decline in the expression pattern of both c-Jun and c-Fos genes, which might be responsible for the decline in the number and differentiation of spermatogonia, resulting in the reduction of fertility [
17].