| Objective To explore the correlation between the expression of Cx43 in hippocampus and the occurrence and development of depression after ischemic stroke.Method 1.The endothelin-1 intracortical injection method was used to establish a focal ischemic model rat.;adopt lonely feeding method combined with chronic unpredictable mild stress(Churonic unpredictable mild stress,CUMS)to establish depression model rats;sequence of the above two methods Establish post-stroke depression(PSD)rats consistently.The rats were divided into control group,simple stroke group,simple depression group,and PSD group according to the corresponding requirements,with 16 rats in each group.2.The neurological deficits in rats with cerebral ischemia were evaluated with the Longa method;The changes in the weight of experimental rats were also monitored and recorded;Moreover,the sucrose water consumption test was used to observe the sense of taste of rats;An open field test(OFT)was applied to test the autonomic groping level and exercise vitality of the experimental rats.The obtained data was applied to evaluate the depression level of the model.3.The real-time PCR was applied to detect the expression of connexin43 m RNA in the hippocampus of rats in each group and The imunohistochemistry and Western blot were used to detect the expression of Cx43 in the hippocampus of each group of rats.4.Pearson correlation analysis was performed on the relative expression levels of Cx43 and depression severity indexes(horizontal exercise distance in the open field experiment, number of vertical exercises,and sugar water consumption in the sucrose consumption experiment)detected by Western blotting on PSD rats.5.Statistical analysis was performed on the recorded research data based on the SPSS 23.0 software.Results 1.Rat weight change At 7 days after operation,there was a statistically significant difference in the number of vertical movements between the PSD group and the simple stroke group compared with the control group(P<0.01);There was no statistically significant difference between the PSD group and the simple stroke group,and the simple depression group and the control group(P>0.05);28 days after operation,the weight of rats in the PSD group,the simple stroke group and the simple depression group was significantly less than that in the control group.The differences were was statistically significant(P<0.01).The weight of the rats in the PSD group were less than that in the simple stroke group,which was statistically significant(P<0.01),while there was no statistic significance in the difference between the weight of the rats in the simple depression group and the PSD group(P>0.05).2.Behavioral determination(1)At 7 days after operation,sucrose water consumption in the PSD group and the simple stroke group was lower than that in control group,and the difference was statistically significant(P<0.01).There were no statistically significant differences between the PSD group and the simple stroke group and between the simple depression group and the control group(P>0.05).28 days after operation,the sucrose water consumption of rats in the PSD group and the simple depression group was significantly reduced.Compared with the control group and the simple stroke group,the PSD group had a statistically significant difference(P<0.01).The differences between the simple depression group and the control group as well as the simple stroke group were also statistically significant(P<0.05).But there was no statistic significance in the difference in the sucrose water consumption between the simple stroke group and the control group,and between the simple depression group and the PSD group(P> 0.05).(2)At 7 days after operation,the number of vertical exercise in the PSD group and the simple stroke group was statistically significant compared with the control group(P< 0.01).There were no statistically significant differences between the PSD group and the simple stroke group and between the simple depression group and the control group(P> 0.05).28 days after operation,the horizontal movement distances of rats in the PSD group and the simple depression group were significantly shorter than those in the control group and the simple stroke group,and the differences were statistically significant(P<0.01).But there was no statistic significance in the differences between the simple depression group and the PSD group,and between the control group and the simple stroke group(P>0.05).(3)At 7 days after operation,the number of vertical exercise in PSD group and stroke group was statistically significant compared with the control group(P<0.01).There were no statistically significant differences between the PSD group and the stroke group and between the depression group and the control group(P>0.05).28 days after operation,the number of vertical movements of rats in the PSD group and the simple depression group were less than those in the control group and the simple stroke group,and the difference was statistically significant(P<0.01).But there was no statistic significance in the differences between the depression-only group and the PSD group,and between the control group and the stroke-only group(P>0.05).3.RT-PCR detection The expression of Cx43 m RNA in hippocampus of the rat in the PSD group was weaker than those in the control group,the stroke group and the depression group,the differences were statistically significant(P<0.01).Moreover,the relative expressions of Cx43 m RNA in the rat of the stroke group and the depression group were stronger than that in the controlgroup,and the difference was statistically significant(P<0.01).Besides,the expression of Cx43 m RNA in the hippocampus of the rat model in the simple stroke group was stronger than that in the simple depression group,and the difference was statistically significant(P<0.05).4.Immunohistochemical detection The average optical density value of the hippocampal Cx43 in the PSD rat was lower than those in the control group,the stroke group,and the depression group,and the differences were statistically significant(P<0.01).The average optical density value of the hippocampal Cx43 in the depression group was higher than that in the control group and the stroke group.The difference was statistically significant(P<0.05);but there was no statistic significance in the difference between the simple stroke group and the control group(P> 0.05).5.Western blot detection The relative expression of Cx43 protein in the hippocampus of the rat in the PSD group was weaker than those in the control group,the simple depression group,and the simple stroke group,and the differences were statistically significant(P<0.01).In addition,the relative expression of the Cx43 protein in the hippocampus of rats in the simple depression group was stronger than that in the control group,and the difference was statistically significant(P<0.05).But there was no statistic significance in the difference between the control group and the simple stroke group.6.Pearson correlation analysis The relative expression of hippocampal Cx43 protein in PSD group was positively correlated with sugar water consumption,horizontal exercise distance and number of vertical exercises(r=0.791,P<0.05;r=0.799,P<0.05;r=0.727,P<0.05).Conclusions The expression of Cx43 in hippocampus of PSD rats is down-regulated,The down-regulation of Cx43 expression is negatively correlated with the degree of depression of PSD,Cx43 participates in the occurrence and development of PSD,The down-regulation of Cx43 expression is a contributing factor to the occurrence of PSD. |
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