Changes of testicular phosphorylated proteins in response to restraint stress in male rats

Objective： To investigate male reproductive parameters via changes of potential testicular protein markers in restraint-stress rats. Methods： Male Sprague-Dawley rats were divided into two groups （non-immobilized control and restraint-immobilized/stress groups, n=8 each group）. The stress animals were immobilized （12 h/d） by a restraint cage for 7 consecutive days. All reproductive parameters, morphology and histology were observed and compared between groups. In addition, the expression of steroidogenic acute regulatory （STAR） and phosphotyrosine proteins （previously localized in Sertoli and late spermatid cells） in testicular lysate was assayed by immuno-Western blotting. Results： Testosterone level, sperm concentration and sperm head normality of stress rats were significantly decreased while the corticosterone level was increased as compared with the control （P〈0.05）. Histologically, stress rats showed low sperm mass in epididymal lumen and some atrophy of seminiferous tubules. Although the expression of testicular STAR protein was not significantly different between groups, changed patterns of the 131, 95, and 75 kDa testicular phosphorylated proteins were observed in the stress group compared with the control group. The intensity of a tes- ticular 95-kDa phosphorylated protein was significantly decreased in stress rats. Conclusions： This study has demonstrated the alteration of testicular phosphorylated protein patterns, associated with adverse male reproductive parameters in stress rats. It could be an explanation of some infertility in stress males.