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.
ABSTRACT
Aim To assess the effects of Trillium Tschonoskii Maxim ( TTM ) decoction on Tau protein phosphorylation and synaptic development in AD model rats induced by high activity GSK-3β. Methods The SD rats were divided into five groups of ten animals, named sham-operated group ( blank group) , AD model group, TTM group (0. 5, 0. 25, 0. 125 g·kg-1 · d-1 ) . Treatment group received gavage once a day for seven days with TTM decoction, while other groups by gavage once a day for seven days with drinking water. On 2nd day by gavage, Morris water maze test was used to assess the spatial learning and memory ability of the rats. After five days' training, rats in the treat-ment groups and AD model group were injected wort-mannin ( WT, PI3K specific inhibitor ) and GF-109203X (GFX, PKC specific inhibitor) (100 μmol ·L-1 of each, total volume of 10 μL) into the right lateral ventricle. Western blot was used to detect the levels of phosphorylation Tau protein at multiple sites and the expression level of PI3K, Akt, PKC, GSK-3β(S9, T216) and synapse-associated proteins. Immu-nohistochemical method was used to detect the hyper-phosphorylation of Tau protein in hippocampus of rats. Golgi staining was applied to detect the number and morphological changes of synaptic development and dendritic spines. Nissl' s staining was employed to ob-serve the development of neonatal neurons in hippo-campus and cortex. Results Western blot showed that the phosphorylation level of Tau in hippocampus increased in model group, and the activity of GSK-3βwas up-regulated. Among them, however, in middle dose TTM group, the phosphorylation level of Tau in hippocampus decreased and the activity of GSK-3βde-creased. The expression levels of p-PKC and p-Akt in low and middle dose treatment group were higher than those in model group, thus increasing the activity of PKC and Akt to inhibit the activity of GSK-3β kinase. Immunohistochemistry also indicated that TTM could decrease the biological effects of Tau phosphorylation in hippocampus of AD rats. Western blot showed that TTM could increase the expression levels of synapsin-1 , syn-aptophysin and GluR-1 in hippocampus of AD rats. Nissl staining showed that the number of Nissl bodies in hippocampal neurons of AD model group were signif-icantly fewer than those of sham operation group, which could be increased by TTM middle and high dose group, and the complexity and dendritic spine density of hippocampal neurons in AD rats could be en-hanced as well. Conclusion TTM can effectively im-prove the cognitive function of AD rats induced by the increase of GSK-3β activity, and its possible mecha-nism may be via down-regulating the activity of GSK-3β and inhibiting the phosphorylation of tau protein and promoting the development of neurons.