17?-estrogen Reduced The Up-regulation Of Clathrin Heavy Chain Through Estrogen Receptor ? Rather Than Estrogen ? After TBI

Objective:Traumatic brain injury(TBI)is a kind of brain injury caused by external forces,which lead to death of many soldiers and civilians.It is generally believed that 17?-estrogen(E2)has a positive effect in TBI treatment.E2 plays a neuroprotective role through classical receptor-and nonclassical receptor-pathway.However,the pharmacological mechanism of E2 has not been fully understood.Clathrin is composed of three heavy chain and three light chain.The main functions of clathrin heavy chain(CHC)are involved endocytosis,protein assembly and in mitosis.In this study,use in vivo and in vitro model,we mainly try to explore the change of CHC and whether it has a protective or harmful effect in the central nervous system(CNS),and whether E2 affects the expression of CHC.Methods:Using the improved free-falling method,the 40 g weight was increased by 20 cm and then dropped freely.In order to detect the expression of CHC time-dependent change after TBI,it was analyzed by western blotting.When the highest expression of CHC was determined based on the above results,saline solution or E2 were injected at 30 min after TBI,respectively.The result suggested that E2 would reduce the levels of CHC.We also used E2 to combine with estrogen receptor antagonists(ICI 182780,MPP or PHTPP)to explore the mechanism in vivo model,the groups are sham group,vehicle group,E2 group,E2+ICI 182780 group,E2+MPP group,and E2+PHTPP group.In order to authenticate the result in vivo,primary cortical neurons and astrocytes injury model were established.Neural cell injury was induced by lipopolysaccharide(LPS),CHC expression was detected at different time point by western blotting.After the highest expression of CHC was determined,pitstop@2 or 17?-estradiol were used to treat primary neurons and astrocytes.After verifying that 17?-estradiol could reverse the expression of CHC,we used E2 to combine with estrogen receptor antagonists(ICI?MPP or PHTPP),the groups were control group,LPS group,E2+LPS group,E2+ICI 182780+LPS group,E2+MPP+LPS group,and E2+PHTPP+LPS group,respectively.Result:In the cortex,hippocampus,primary cortical neuron and astrocytes,the expression of clathrin heavy chain increased firstly and then decreased.E2 reduced the up-regulation of CHC through estrogen receptor a pathway rather than estrogen receptor ?pathway in the cortex,hippocampus in vivo,primary cortical neurons and astrocytes in vitro.pitstop@2 could also reserve CHC expression,suppress autophagy and inhibit apoptosis.Conclusion:Our data suggested the increased expression of CHC was a damage effect in TBI.17?-estrogen reduced the up-regulation of clathrin heavy chain through the estrogen receptor a pathway rather than the estrogen receptor ? pathway after TBI.