| Objective:The guinea pig cochlear vascular striate PCs were used as the research object to investigate the relationship between regulation of expression and function of BKCa on PCs by estrogen receptor GPER and age-related hearing impairment.Methods:Animal experiments:8 week old healthy guinea pigs were randomly divided into Control group,D-galactose model group（D-galactose,D-gal）and D-gal+G1 group.Morris water maze was used to detect the changes of behavior in different groups of guinea pigs.UVD spectrophotometry was used to detect the activity of SOD and MDA in different tissues of guinea pigs.The auditory brainstem response（ABR）was used to detect the changes of hearing in different groups of guinea pigs.The expression of BKCa and EPER on vascular striate PCs was detected by immunofluorescence technique.The effect of GPER on BKCa current on PCs was detected by patch clamp technique.Cell experiments:primary cultured guinea pig cochlear vascular pericytes,the experiment was divided into Control,D-gal,D-gal+G1,D-gal+G1+SQ22586 and D-gal+G1+H89 groups.The expression of BKCaa and cAMP/PKA on PCs was detected by immunofluorescence technique and Western technique.The effect of GPER on BKCa current on PCs was detected by patch clamp technique.Results:（1）Morris water maze behavior test showed that the spatial learning ability and memory of D-gal group were damaged.The results of SOD activity and MDA content showed oxidative stress damage in D-gal group;（2）compared with Control group The ABR threshold was increased and the amplitude of I wave was significantly decreased in the D-gal group（P<0.01）.The ABR threshold was decreased and the amplitude of the I wave was increased in the D-gal+G1 group compared with the D-gal group（P<0.01）.3)Compared with the Control group,the GPER expression in the D-gal group was significantly decreased（P<0.01）,and the D-gal+G1 group was not different from the D-gal group;（4）Compared with the Control group,the expression of BKCa was significantly decreased in the D-gal group（P<0.01）.After G1 intervention,the expression of BKCa in the vascular striate PCs was increased.（5）Compared with the Control group,The net current of BKCa in the vascular striate PCs was significantly reduced in the D-gal group（P<0.01）.After G1intervention,the net current of BKCa in vascular striate PCs increased（P<0.01）.（6）Compared with the Control group,the expression of BKCa in PCs of D-gal group was significantly decreased（P<0.01）.After G1 intervention,the expression of BKCa in PCs was significantly increased,but cAMP blocker was given.（SQ22586）and PKA blocker（H89）can partially reverse the up-regulation of BKCa on PCs by G-1;（7）Compared with Control group,the net current of BKCa in PCs of D-gal group is significantly reduced（P<0.01）,compared with the D-gal group,the net current of BKCa in PCs increased in the D-gal+G1 group（P<0.01）.But after cAMP blocker（SQ22586）and PKA blocker（H89）were administered,the up-regulation of BKCa current density on PCs can be partially inhibited by G-1.Conclusions:GPER may activate the cAMP/PKA signaling pathway to up-regulate the expression and function of BKCa on vascular pericytes,thereby exerting a protective effect on age-related hearing impairment. |
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