OBJECTIVETo study the effects of salidroside on the function and ultramicro-pathological change of the hypothalamic-pituitary-gonadal (HPG) axis of male rats in experimental navigation and intensive exercise.

METHODSSix-week SD rats were randomized into 3 groups: non-stress control (NC, n = 10), training control (TC, n = 12) and salidroside treatment (ST, n = 12) group. Blood samples were collected from the NC rats that did not receive any stimulus after a 7-day intragastric administration of saline. The TC rats underwent a 10-day running training with increasing load on the treadmill followed by a 7-day intragastric administration of saline. The ST rats were subjected to the same process of running training as the TC group and received intragastric administration of salidroside. Then blood samples were immediately obtained and the levels of testosterone (T), corticosterone (CORT), adrenocorticotropic hormone (ACTH), luteinizing hormone (LH) and gonadotropin-releasing hormone (GnRH) measured by radioimmunoassay. The testis histopathology was observed by HE staining, and the ultrastructural changes of the pituitaries and testes investigated by electron microscopy.

RESULTSThe serum T level was significantly lower in the TC than in the NC group, but showed no significant difference between the ST and NC groups. HE staining revealed no significant difference in testis histopathology among the 3 groups. Ultramicro-pathology showed that the secretory granules of the pituitary cells were significantly reduced in the TC rats compared with the NC ones; the number of the granules significantly increased in the ST group compared with the TC rats; and mitochondrial swelling, increase of electron density and decrease/disappearance of mitochondrial cristae were observed in the Leydig cells of the TC rats. But no significant differences were found in the testicular cells between the ST and NC groups.

CONCLUSIONNegative psychological stress and intensive exercise can significantly suppress the function of the HPG axis in rats. Salidroside therapy has protective effect on the HPG axis.