RESUMO
Objective To study the effective fraction and mechanism of Lycium barbarum leaves on improving learning and memory ability of subacute aging mice induced by D-galactose injection.Methods The model of subacute aging mice was developed by injection of D-galactose subcutaneously,and different extracts of Lycium barbarum leaves were prepared.The effects of the extracts of Lycium barbarum leaves on the learning and memory ability of model mice were evaluated by Y maze experiment and new object recognition experiment.The pathomorphological changes of hippocampus in mice were observed by hematoxylin-eosin and Nissl staining.The levels of brain-derived neurotrophic factor(BDNF),nerve growth factor(NGF),glial cell line-derived neurotrophic factor(GDNF),tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),interferon-γ(IFN-γ)and interleukin-10(IL-10)in hippocampus of mice were detected by enzyme-linked immunosorbent assay.The activities of superoxide dismutase(SOD)and the contents of glutathione(GSH)and malondialdehyde(MDA)in hippocampus of mice were detected by related assay kits.Detection of apoptosis in the hippocampal region of mouse brain tissue using the TUNEL method.Western blotting analysis was used to detect the expressions of antioxidant proteins Nrf2,HO-1 and apoptotic proteins Caspase-3,Caspase-9 in hippocampus of mice.Results The water extraction part and 80%alcohol precipitation supernatant part of Lycium barbarum leaves significantly improved the learning and memory ability of model mice,improved the pathological damage of hippocampus in mice,increased the number of Nissl bodies in hippocampus of mice,and promoted the expression of neurotrophic factors BDNF,NGF and GDNF,and promoted the expression of neurotrophic factors BDNF,NGF and GDNF.Pro-inflammatory factors TNF-α,IL-1β and IFN-γ expression declines while anti-inflammatory factor IL-10 expression rises.The activity of SOD and the expression of GSH were increased,and the expression of MDA was decreased.Increase the expression of Nrf2 and HO-1 antioxidant proteins;reduce the expression of Caspase-3 and Caspase-9 apoptosis pathway proteins.Inhibition of apoptosis in the hippocampal region of mouse brain tissue using a model.Conclusion The water extracts and 80%alcohol precipitation supernatant extracts of Lycium barbarum leaves are the effective fractions of Lycium barbarum leaves to improve the learning and memory ability of D-galactose-induced subacute aging mice,and its mechanism might be related to the inhibition of neuronal apoptosis caused by oxidative stress and inflammation.