Changes in gonadal function at different stages of chronic restraint stress-induced depression animals.

The aim of this study was to determine the time-dependent changes in adolescent male gonadal function due to chronic restraint stress (CRS)-induced depression in a rat model and to elucidate the underlying mechanism. CRS was established in adolescence male Wistar rats by placing the animals in a cylinder for 3 h every day for 28 days, during which time the general behavior and serum hormonal levels were routinely monitored. The CRS model rats showed anxiety-like behavior in the open field test (OFT) and sucrose consumption test, and their body weights also decreased significantly on the 14th, 21st and 28th days. The CRS rats showed a significant decrease in serum 5-hydroxytryptamine (5-HT) after 14 days of restraint and an increase in the CORT and NE levels after 21 days of restraint, while the serum GnRH levels increased significantly on the 14th and 21st days and decreased significantly over the last 7 days. In contrast, the FSH and LH levels decreased significantly from the 14th day to the 28th day, while the PRL and E2 levels were significantly higher during the same time period compared to those of the controls. The serum T levels also decreased significantly in the CRS group on the 21st and the 28th days, with the lowest levels occurring on day 28. Histopathological examination showed that testicular damage was aggravated during CRS. In addition, the levels of MDA, CytC and 8-OHDG increased significantly, while those of SOD decreased significantly in the CRS rats testicular mitochondrial. These results indicate that the gonadal function is altered at different stages of CRS, which can be attributed to changes in neurotransmitters and PRL that affect GnRH levels in the hypothalamus and subsequently regulate the serum T levels. In addition, excessive production of CORT impairs the testicle in adolescent period via enhanced oxidative damage, which eventually leads to gonadal dysfunction.