The Role Of GPR30 In Hippocampal Neuron Injury And Effect On PSD95 In Castrated Rats With Chronic Stress

Objective To establish a SD rat model of castration combined with chronic stress and to observe the damage of hippocampal neurons and the expression of estrogen membrane receptor GPR30 protein,pAkt,Akt and PSD95 protein in hippocampus,understanding the mechanism of estrogen protecting hippocampal neurons.Methods Female SD(Sprague Dawley rats were randomly divided into blank control group,stress+sham group,castration+stress model group,castration+stress+ E2-BSA group and castration+stress+E2-BSA+G15 group,with 12 rats in each group.There was no castration in the blank control group,but only castration sham operation in the stress+ sham group and DMSO group.Castration+stress model group,castration+stress+E2-BSA group and castration+stress+E2-BSA+G15 group were ovariectomized.The blank control group did not perform the operation of lateral ventricular localization,while the stress+sham group only cut the skin,drilled holes and did not perform the operation.DMSO group,castration+ stress model group,castration+stress+E2-BSA group and castration+stress +E2-BSA+G15 group perform the operation.Rats in blank control group and DMSO group were fed normally.The DMSO group was given 0.5% DMSO solution,5μL every day.Stress+sham group,castration+stress model group,castration+stress+E2-BSA group and castration+stress+E2-BSA+G15 group were given chronic unpredictable stress.Every day,one is selected,and the same kind of stimulus can not be given continuously,so that it is unpredictable.At the same time,castration+stress+E2-BSA group and castration+stress+E2-BSA+G15 group were given corresponding drug intervention and lasts for 28 days.Open field test and 2% sucrose consumption test detect behavioral changes of rats.The morphological changes of hippocampal neurons were observed by Nissl staining.The expression of PSD95 and pAkt protein in hippocampus of GPR30 was detected by immunohistochemistry.The positive expression of GPR30、Akt、pAkt and PSD95 protein was detected by Western blot.Results 1 The results of open field test: the scores of the castration+stress model group were lower than those of the blank control group and the stress+ sham group.At the fourth week of administration,the scores of open field test decreased in castration+stress model group and castration+stress+ E2-BSA +G15 group.2 The results of 2% sucrose solution consumption :at the fourth week of administration,the consumption of 2% sucrose solution in castration+stress model group and castration+stress+ E2-BSA +G15group decreased.3 Nissl staining :the hippocampal neurons in the castration+stress+ E2-BSA group had complete morphology,regular arrangement of cells,more Nissl bodies,and scattered hippocampal neurons in castration+stress model group.The morphology of hippocampal neurons was incomplete,and the staining was shallow,and the Nissl body was less after administration of GPR30 inhibitor G 15.4 The results of immunohistochemistry :(1)GPR30 protein was mainly expressed in the membrane and cytoplasm of hippocampal neurons,but not in the nucleus.In the CA3 and DG regions of hippocampal neurons,the expression of GPR30 protein was decreased in castration+stress model group and castration+stress+E2-BSA+G15 group compared with the blank control group.(2)The expression of PSD95 protein in hippocampal neurons was decreased in castration+stress model group and castration+stress+E2-BSA+G15 group compared with the blank control group,while the expression of PSD95 protein was increased in castration+stress+E2-BSA group compared with the castration+stress model group.(3)The expression of pAkt protein in the hippocampal neurons was decreased in castration+stressmodel group and castration +stress+E2-BSA+G15 group compared with the blank control group,while the expression of pAkt protein was increased in castration +stress+ E2-BSA group compared with the castration+stress model group.5 The results of Western blot :(1)Compared with the blank control group,the expression of GPR30 protein in castration+stress model group and castration+stress+E2-BS+G15 group decreased.(2)Compared with the blank control group,the expression of PSD95 protein in castration+stress model group and castration+stress+E2-BSA+G15 group decreased.(3)Compared with the blank control group,the relative expression of pAkt and Akt protein decreased in castration+stress model group and castration+stress+E2-BSA+G15group.Conclusion 1 E2-BSA intervention alleviated the injury of hippocampal neurons in ovariectomized SD rats with chronic stress.2 E2-BSA intervention increased the expression of GPR30 and PSD95 protein in hippocampal neurons of ovariectomized rats with chronic stress.3 E2-BSA can activate Akt signaling pathway through GPR30 to increase the positive expression of PSD95 protein,which may be one of the mechanisms of estrogen to play a protective role in neurons.