Abstract: Objective To explore the effect of cerebroprotein hydrolysate injection ( CHI) on learning and memory impairment caused by sevoflurane anesthesia in rats, and analyze its possible mechanism of action. Method Thirty-two rats were randomly divided into sevoflurane group, CHI high-dose group, CHI low-dose group and control group. The sevoflurane group inhaled 2% sevoflurane for 2 hours a day for 7 days. Before the daily inhalation of sevoflurane, 1 200 μL of CHI was injected into the tail vein of the CHI high-dose group and 300 μL of CHI was injected into the tail vein of the CHI low-dose group. The control group did not inhale sevoflurane, and injected normal saline into the tail vein. The water maze experiment was used to record the learning and memory abilities of rats; HE staining was used to observe the histopathological changes of rat hippocampus; ELISA was used to detect MDA and SOD levels in rat hippocampus; TUNEL was used to detect the apoptosis of rat hippocampal neurons; RT-qPCR was used to detect the expression of SYT1 mRNA in hippocampus. Western blot was used to detect the expression of SYT1, Bax, Bcl-2 and cleaved-Caspase3 protein in the hippocampus of each group. Result Compared with the control group, the escape latency was significantly increased in the sevoflurane group ( P< 0. 05) , the number of crossing platforms was significantly reduced ( P < 0. 05) , the residence time of the platform was significantly shortened ( P< 0. 05) , the neuron cells in the hippocampus were scattered, the borders were unclear, the nuclei were constricted, vacuoles appeared, the color was dark, the apoptosis rate of neurons in hippocampus was significantly increased ( P<0. 05) , MDA, Bax and cleaved-Caspase3 proteins were significantly increased, and SOD, Bcl-2, SYT1 mRNA and proteins were significantly reduced ( P<0. 05) . Compared with the sevoflurane group, the escape latency of the CHI high-dose group was significantly shortened ( P < 0. 05 ) , the number of crossing platforms was significantly increased ( P < 0. 05 ) , the residence time of the platform was significantly prolonged ( P < 0. 05 ) , the neuron cells in the hippocampus were arranged relatively tightly, the nucleus shrinkage and vacuoles were improved, the apoptosis rate of hippocampal neurons was significantly decreased ( P<0. 05) , MDA, Bax, cleaved-Caspase3 protein content decreased significantly, SOD, Bcl-2, SYT1 mRNA and proteins were significantly increased ( P < 0. 05) ; Compared with the model group, the CHI low-dose group had no significant changes in the various indicators of rats ( P > 0. 05) . Conclusion Pre-administration of high-dose CHI before inhalation of sevoflurane can improve learning and memory impairment in rats caused by sevoflurane anesthesia, which may be related to the reduction of oxidative stress injury, inhibition of hippocampal neuronal cell apoptosis and increase of SYT1 expression.
