Changes And Mechanisms Of AQP-5 In The Submandibular Of Ovariectomized Rats

Objective:We observed the expression of AQP-5 on low estrogen status,and we explored how estrogen regulates AQP-5 distribution by the SOCE and TRPV1 pathway.Methods:A total of 90 Sprague-Dawley female adult rats were randomly and equally divided into SHAM,OVX and OVX+E groups.Two weeks after being ovariectomized,rats were treated with?-estradiol for 4 weeks.Serum estradiol concentrations were thereafter detected using immunoradiometry,while expression of AQP-5,STIM1,Orai1,M1,M3,NOS-1andTRPV1inthesubmandibularglandwereevaluatedusing immunohistochemical?IHC?and immunofluorescence?IF?methods.Expression STIM1and Orai1 were evaluated using western blotting.Ca²⁺concentrations in submandibular acinar cells were measured by Ca²⁺imaging.And the changes of acetylcholinesterase?AchE?in the submandibular gland were observed by acetylcholinesterase staining.Results:Serum estradiol concentrations significantly declined after rat ovariectomization.AQP-5 was mainly expressed in acinar cells of submandibular gland.In OVX rats,no significant changes in AQP-5 expression were noted.However,apical membrane AQP-5expression significantly declined while lateral membrane expression significantly increased.After estrogen intervention,apical membrane AQP-5 expression increased while that of the lateral membrane decreased;findings were similar to those of SHAM rats.NOS-1,TRPV1,M1 and M3 were mainly expressed in acinar cells and ductal cells.After ovariectomy,the expression of NOS-1,M1 and M3 was significantly lower than that of SHAM group.After the intervention of estradiol,the level of SHAM was restored.Expression of STIM1 and Orai1,although initially decreased in OVX rats,increased to SHAM rat levels after estrogen intervention.Ca²⁺imaging revealed that Ca²⁺concentrations in submandibular acinar cells of OVX rats significantly declined,but increased to SHAM rat levels after estrogen treatment.The results of acetylcholinesterase staining showed that the expression of AchE in the submandibular gland was significantly increased after ovariectomy,and there was no significant improvement after estrogen intervention.Conclusion:These results suggest that both STIM1-Orai1 and TRPV1 pathway may induce salivary secretion of submandibular gland by regulating AQP-5 in perimenopausal.