Chronic Stress Increases the Tyrosine Phosphorylation in Female Reproductive Organs: an Experimental Study

Background: Changes in tyrosine-phosphorylated (TyrPho) protein expressions have demonstrated stress in males. In females, chronic stress (CS) is a major cause of infertility, especially anovulation. However, the tyrosine phosphorylation in the female reproductive system under stress conditions has never been reported. Objective: To investigate the alteration of TyrPho protein expression in ovary, oviduct, and uterus of CS rats. Materials and Methods: In this experimental study, 16 female Sprague-Dawley rats (5 wk: 220-250 gr) were divided into control and CS groups (n = 8/group). Every day, the CS animals were immobilized within a restraint cage and individually forced to swim in cold water for 60 consecutive days. Following the stress induction, the ovary, oviduct, and uterus of all rats were observed for their morphologies. The total protein profiles of all tissues were revealed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) before detecting TyrPho proteins using western blot. Intensity analysis was used to compare the expression of proteins between groups. Results: The results showed that the morphology and weights of ovary and oviduct in the CS group were not different from control. In contrast, the CS significantly increased the uterine weight as compared to control. Moreover, the expressions of TyrPho proteins in the ovary (72, 43, and 28 kDas), oviduct (170, 55, and 43 kDas), and uterus (55, 54, and 43 kDas) were increased in CS group as compared to those of control. Conclusion: The increased expressions of TyrPho proteins in ovary, oviduct, and uterus could be potential markers used to explain some mechanisms of female infertility caused by chronic stress. Key words: Ovary, Oviduct, Uterus, Phosphorylation