Effects Of Ketamine On Rat Nerve Tissue Autophagy

PartⅠObjective: To investigate the effects of ketamine on the autophagy of cultured astrocytes induced by glutamate in diferent time points.Methods: Mixed astrocytes were obtained from cerebral cortical tissue of newborn rats. Purified astrocytes were achieved by mechanical shaking and differential adhesions methods.The astrocytes were then randomly divided into 3 groups:control group(C)in which D-Hank's solution 366μL was added;glutamate group(G) in which glutamate was added(the final concentration was 125μmol/L);glutamate-ketamine group(GK) in which glutamate was added first(the final concentration was 125μmol/L)and 30 minutes later ketamine was added(the final concentration was 1mmol/L).Immunofluence staining was used to characterize the astrocytes and analyze the expression of LC3.The expression of beclin1,bcl2,LC3 were analyzed by Western blot.Results: Immunofluorescence results showed that compared with group C the expression of LC3Ⅱin group G were higher,but compared with group G the expression of LC3Ⅱin group GK were lower.Western blot results showed that the expression of LC3Ⅱ/LC3Ⅰ,beclin1 and beclin1/ bcl2 were higher in group G than group C, The expression of bcl2 was lower in group G than group C.The expression of LC3Ⅱ/ LC3Ⅰ, beclin1 and beclin1/ bcl2 were lower in group GK than group G, The expression of bcl2 was higher in group GK than group G. Conclusions: 125μmol/L glutamine can induce autophagy,1mmol/L ketamine can inhibit autophagy and play a certain role in cerebral protection.PartⅡObjective: This study to exam the ratio of LC3Ⅱ/ LC3Ⅰand the expression of beclin1 in the hippocampus of rat after repeated intraperitoneal injection of a low dose of ketamine.Methods: 30 adult SD rats were randomly divided into ketamine group and saline group.Ketamine group rats were respectively administered intrape ritoneally with 5mg/kg ketamine. Saline group rats were respectively administered intrape ritoneally with equal volume of 0.9% saline solution. Every half an hour a time, a total of 5 times.The hippocampus of ketamine group rats were removed at 1,3,6,12,24,48 hours after the last administration.Western blot was used to examine the ratio of LC3Ⅱ/LC3Ⅰand the expression of beclinl at the hippocampus at different times. Application of statistical analysis to compare ketamine group and saline group differences in protein expression.Results: The ratio of LC3Ⅱ/LC3Ⅰand the expression of beclin1 in rat hippocam- pus were higher in ketamine group compared with saline group.The level of beclinl started to elevate 6 hours after administer and strongly expressed at 12 hours,24 hours,48hours. The ratio of LC3Ⅱ/LC3Ⅰstarted to elevate 1 hours after administer and peaked at 6 hours.Conclusions: The expression of LC3 and beclinl in rat hippocampus upgraded after repeated intraperitoneal injection of a low dose of ketamine, and relevanted with time,which shows that repeated intraperitoneal injection of a low dose of ketamine can promote the occurrence of autophagy, autophagy increase is a toxic reaction to ketamine.