An Experimental Study On Time-dependent Expression Of BDNF,NMDAR1 And Cognitive Impairment After Traumatic Brain Injury In Rats.

Objective:To establish a rat animal model of brain traumatic injury, and determine the time point. To evaluate change in brain-derived neurotrophic factor (BDNF), N-methyl-D - aspartate receptor1(NMDAR1) expression and cognitive function in rats after brain injury.Methods:1.A total of 72 healthy, male, Sprague Dawley, rats were selected for this study. Rat models of mild and moderate traumatic brain injury were created by percussion, according to Feeney's method (n = 24, each group). A bone window was made in rats from the sham operation group (n = 24), but no attack was conducted.2. determine time points : according to the adoption of the balance test, walking test and memory test ,to determine time points.3.To evaluate BDNF and NMDAR1 at different time points in different parts of the brain by immunohistochemistry, analyze the trends of BDNF and NMDAR1 after brain injury.Results:1.Cognitive impairment was aggravated at day 2,and recovered to normal at days 3 and 7 in rats from the mild and moderate traumatic brain injury groups.2. BDNF expression in the rat frontal lobe cortex, hippocampus and basal forebrain was increased at 1 day, decreased at day 2, and then gradually increased in the mild and moderate traumatic brain injury groups. BDNF expression was greater in rats from the moderate traumatic brain injury group than in the sham operation and mild traumatic brain injury groups (P < 0.05).3. NMDAR1 expression in the rat frontal lobe cortex, hippocampus and basal forebrain was increased at 1 day, decreased at day 2, and then gradually increased in the mild and moderate traumatic brain injury groups. NMDAR1 expression was greater in rats from the moderate traumatic brain injury group than in the sham operation and mild traumatic brain injury groups (P < 0.05).Conclusion:BDNF,NMDAR1 expression in the rat frontal lobe cortex, hippocampus and basal forebrain is correlated to cognitive impairment after traumatic brain injury. BDNF has a protective effect on cognitive function in rats following injury.NMDAR1 has a damage effect.