Effect of Trillium tschonoskii Maxim on expression of miRNA-155-3p in rats with brain aging induced by D-gal / 中国药理学通报

ABSTRACT

Aim To explore the effect of Trillium tschonoskii Maxim (TTM) on the expression of miR-NA-155-3p in rats with brain aging induced by D-gal. Methods Fifty SD rats were divided into five groups randomly. The rats were administered with 0. 9% normal saline (NS) subeutaneously every day in control group, 200 mg • kg • d-1 of D-galactose (D-gal) daily inD-galmodelgroup,and50,100and200mg • kg • d-1 of TTM by gavage 2 hours before D-gal injection everyday in TTM treatment groups for 6 weeks. After 5 weeks, Morris water maze was used to test the ability of spatial learning and memory every day. At the 6th week, rats were sacrificed arid hippocampi were tested by Nissl staining and 8-OHdG immunohistochemical (8-OHdC) staining. The expression of miR-155-3p was determined by Real-time PCR, and the levels of Rheb. mTOR, p-inTOR and p70S6K were detected by Western blot. Results The length of escape latency time and path distance in five groups showed a trend of shortening gradually in the orientation navigation experiments. The average escape latency and the distance in D-gal group were longer than those in control group and TTM group (P <0. 01 and 0. 05) , and the number of crossing platform limes less too (P < 0. 05). The arrangement of neurons was irregular and the intercellular space widened in D-gal group compared with those in TTM group by HE staining. There were more Nissl particles in neurons of the hippocampal CA1 area in con-trol group than that in D-gal group, and TTM treatment could increase the number of Nissl bodies-induced by D-gal. Compared with control group, the fluorescence density of 8-OHdG in D-gal group significantly in-creased (P <0. 01) , while that in TTM group was lower than that in D-gal group (P < 0. 05). The expression of miR-155-3p in the hippocampi in D-gal group was significantly higher than that in normal group (P < 0. 05) , while TTM treatment could alleviate D-gal-in-duced increase of miR-155-3p (P < 0. 05) , followed by an increase of the levels of Rheb and p70S6K, and decrease of mTOR. Conclusions The expression of miR-155-3p increased in the hippocampi of aging rats induced by D-gal. TTM could execute the anti-aging process of brain and down-regulate the level of iniR-155-3p through Rheb/mTOR/p70S6K signaling pathway.