Abstract:

Objective To discuss the improvement effect of exogenous brain-derived neurotrophic factor （BDNF） targeted liposomes on the learning and memory abilities of Alzheimer’s disease （AD） model rats， and to clarify its possible mechanism. Methods Thirty-two SD male rats were randomly divided into sham operation group， AD model group， low dose of BDNF group， and high dose of BDNF group. Except for sham operation group， the rats in the other groups were prepared as AD models. The rats in low and high doses of BDNF groups were injected with 1 and 2 μL of exogenous BDNF liposomes via tail vein， respectively. Morris water maze test was used to detect the learning and memory abilities of the rats in various groups； immunohistochemistry staining was used to detect the expression level and distribution of BDNF protein in hippocampus tissue of the rats in various groups； Western blotting method was used to detect the expression levels of phosphorylated Tau （p-Tau） （Thr231） protein in hippocampus tissue of the rats in various groups. Results The Morris water maze test results showed that compared with sham operation group， the escape latency of the rats in AD model group was significantly prolonged （P<0.05）； compared with AD model group， the numbers of crossing platform position and the residence time in target quadrant of the rats in low and high doses of BDNF groups were significantly increased （P<0.05）. The immunohistochemistry staining results showed that compared with AD model group， the expression levels of BDNF protein in cortex and hippocampus tissues of the rats in low and high doses of BDNF groups were significantly increased （P<0.01）. The Western blotting method results showed that compared with AD model group， the expression levels of p-Tau （Thr231） protein in hippocampus tissue of the rats in low and high doses of BDNF groups were significantly decreased （P<0.01）； compared with low dose of BDNF group， the expression level of p-Tau （Thr231） protein in hippocampus tissue of the rats in high dose of BDNF group had no statistically significant difference （P>0.05）. Conclusion Intravenous administration of exogenous BDNF liposomes can improve the learning and memory abilities of AD model rats， and the mechanism may be related to up-regulating the expression level of BDNF protein in cerebral cortex and hippocampus tissue and decreasing the expression level of p-Tau （Thr231） protein in hippocampus tissue.

Key words: Exogenous brain-derived neurotrophic factor liposomes, Alzheimer’s disease, Learning ability, Memory ability, Rats，SD