OBJECTIVETo investigate the protective effect of lycium barbarum polysaccharides (LBP) against heat stress-induced apoptosis of germ cells in rats and its action mechanism.

METHODSNinety male Sprague-Dawley rats were randomly divided into five groups of 18 each: control, heat stress (HS), high-dose LBP, median-dose LBP and low-dose LBP. The rats of the three LBP groups were given LBP by intragastric administration at 100 mg/(kg x d), 50 mg/(kg x d) and 10 mg/(kg x d) respectively for 14 days, and on the 15th day they, together with those of the HS group, were exposed to a heat of 43 degrees C for 30 minutes. At 24 h, 48 h and 7 d after heat stress, the animals were killed by cervical dislocation, followed by observation of the apoptotic germ cells by TUNEL, determination of the expression of Caspase-3 by immunohistochemistry and detection of cytochrome C in the cytosol by ELISA.

RESULTSCompared with the HS group, the three LBP groups showed statistically significant decreases in the apoptosis index (P<0.05), the expression level of Caspase-3 in germ cells (P<0.05) and the concentration of cytochrome C in the cytosol (P<0.05).

CONCLUSIONLBP can inhibit cytochrome C release from mitochondria, decrease the expression of Caspase-3 and hence reduce the apoptosis of germ cells. It thus can be deduced that LBP can protect germ cells against apoptosis via the mitochondrial pathway.