| Objective:To explore the effect of ketamine on depression state of depression rat,normal rat hippocampal microRNA206 and BDNF protein expressions Methods:I.Normal rats were randomly divided into depression group 1,depression group 2 and control group.Rats in depression group 1 and depression group 2 were stimulated by a chronic unpredictable mild stress(CUMS),1 times a day,on 27 consecutive days,rats in control group were fed in normal way.The depression state of rats in all groups were evaluated by open-field,sugar water consumption and forced swimming test;After evaluation,30mg/kg ketamine were administered intraperitoneally(i.p.)in a blind fashion,1 times a day in depression group 1 rats;1 times a day and on 7 consecutive days in depression group 2 rats;0.9%saline were administered intraperitoneally(i.p.)in control group rats in a blind fashion.On the first and 8th day after drug treatment,the depression state in all group rats were again evaluated by open-field,sugar water consumption and forced swimming test.II.Rats were randomly divided into ketamine test group(T,n=3)and saline control group(C,n=3),T group:30 mg/kg ketamine for intraperitoneal injection,C group:0.9%saline for intraperitoneal injection,1 times/day for both groups,on 7 consecutive days.Rats were sacrificed 24 hours after the final treatment,the skulls were removed and hippocampus was dissected and stored at-80℃ for biochemical analyses.The miRNA expression signature in rat hippocampus was investigated by the 6th generation of miRNA array containing more than 1891 capture probes,covering all human,mouse and rat microRNAs.Ⅲ.Rats were randomly divided into ketamine group 1,ketamine group 2,ketamine group 3,saline group 1 and saline group 2;ketamine group 1:30mg/kg ketamine were administered intraperitoneally(i.p.)in a blind fashion,1 times a day;ketamine group 2:30mg/kg ketamine were administered intraperitoneally(i.p.)in a blind fashion,1 times a day,on 7 consecutive days;ketamine group 3:80mg/kg ketamine were administered intraperitoneally(i.p.)in a blind fashion,ltimes a day,on 7 consecutive days;saline group 1:0.9%saline were administered intraperitoneally(i.p.)in a blind fashion,1times a day;saline group 2:0.9%saline were administered intraperitoneally(i.p.)in a blind fashion,ltimes a day,on 7 consecutive days;Rats were sacrificed 24 hours after the final treatment,the skulls were removed and hippocampus was dissected and stored at-80℃ for biochemical analyses.Hippocampal miR-206 levels in all groups were measured with a real-time reverse-transcription PCR(qRT-PCR),hippocampal BDNF protein levels in all groups were measured with western blot.Results:Ⅰ.Compared to the control group rats,the total points obtained in open-field experiment and percent rate in sugar water preference were significantly lowered(P<0.05),and the immobility time in forced swimming test was also extended obviously in depression group 1 and depression group 2 rats(P<0.05);Compared to the pre-treatment,the total points obtained in open-field experiment and percent rate in sugar water preference were obviously increased and the immobility time in forced swimming test was obviously decreased in the first and 8th day after ketamine treatment of depression group 1 and depression group 2 rats,however,the total points obtained in open-field experiment,percent rate in sugar water preference and the immobility time in forced swimming test have no statistic difference in the first and 8th day after saline treatment of control group rats(P>0.05).Compared to the depression group 1 rats,the total points obtained in open-field experiment,percent rate in sugar water preference and the immobility time in forced swimming test have no statistic difference in the 8th day after ketamine treatment of depression group 2 rats(P>0.05).Ⅱ.Under the allowable 5%false discovery rate,we found that 21 microRNAs in the two groups have obvious differences in expression,where 10 microRNAs were significantly down-regulated(the expression of experimental group is at least 1.5 times lower than that of control group on average)and 11 microRNAs were obviously up-regulated(the expression of experimental group is at least 1.5 times higher than that of control group on average).Ⅲ.Compared to saline group,hippocampal microRNA-206 expression in ketamine group 1,ketamine group 2 and ketamine group 3 rats were significantly lower than the corresponding saline group(P<0.05),however,hippocampal BDNF protein expression in ketamine group 2 and ketamine group 3 rats were significantly higher than the corresponding saline group(P<0.05).Conclusion:1.Single,small dose ketamine may obviously and rapidly improve the depression state of depression rat,but multiple,small dose ketamine could not further enhance the antidepressant effect of ketamine.2.Ketamine treatment may result in the abnormal expression of rat hippocampal partial microRNAs.3.Rat hippocampal miR-206 low expression induced by ketamine may be one of the mechanism about BDNF high expression induced by ketamine,but that needs to be further confirmed through cell experiment. |
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