The Effect Of H ₂ 2 On The Function Of Leydig Cells In Rat Testes And The Role Of Peroxiredoxin 2 In Them

Late-onset hypogonadism (LOH) has recently been defined as a syndrome with display of low testosterone for the middle-aged and elderly men. Male aging is typically accompanied with reduced serum level of testosterone, which mainly cause declines in reproductive function, muscle strength, bone density, and other physiological parameters.Testosterone is mainly secreted from testicular Leydig cells. With men aging, the reduction in amount and the functional decline of leydig cells is the core of the disease pathogenesis.Reactive oxygen species (ROS) such as H2O2 and superoxide are produced by cells as by-products of normal cellular metabolism. Accumulation of ROS inhibits the expression of testicular steroidogenic enzyme genes, further downregulates testosterone levels. High concentration of H2O2 in the medium is likely to threat the survival of cells. Peroxiredoxin 2 is a member of peroxiredoxin family, which has the capability to reduce hydrogen peroxide and remove excessive intracellular reactive oxygen molecules. In the present study, Leydig cells were treated with different low-level H2O2. We aimed to determine the effects of low-level H2O2 on testosterone secretion and apoptosis and to analyse the Prdx 2 expression at different time and H2O2 conecentrations in Leydig cells.This study was designed to establish the rat testicular Leydig cell oxidative stress model at low-level H2O2 and to adopt flow cytometry for apoptosis rate, testosterone chemiluminescence for testosterone quantification. We used western blotting and Q-PCR to detect the expression of Prdx 2 in mRNA level and protein level respectively. Our study indicated that as the concentration of H2O2 increases and effecting period prolongs, apoptosis rate elevates and testosterone level drops. We further explored the expression of Prdx 2 in Leydig cells under the effect of low-level H2O2. Prdx 2 protein expression decreased as the concentration of H2O2 increased. Moreover, the protein expression level of Prdx 2 dramatically decreased in Leydig cells with effecting period being prolonged. There was no significant change in Prdx 2 mRNA level.To sum up, low-level H2O2 induced Leydig cells apoptosis and testosterone downproduction, both of which may explain for the occurrence of LOH. Moreover, Prdx 2 level displayed the tendency of continual drop under the effect of low-level H2O2, the possible reason which accounted for this lied with molecular structure transformation. Prdx 2 showed the ability of eliminating the H2O2 by prevent accumulation in Leydig cells, thereby inhibit oxidative stress-induced apoptosis and impairment of testosterone synthesise. Our study provides a potiental target for the treatment and precausion of LOH.