<p style="text-align: center;">JIANG Liyuan, HE Jiaojun, CHEN Xixi, SUN Xuejiao, WANG Xuezhong, ZHONG Shan, CHEN Huade&nbsp;</p><p style="text-align: center;">(The Third Clinical Medical College of Zhejiang Chinese Medical University, Hangzhou&nbsp;<span style="text-align: justify;">310053, China)</span></p><p style="text-align: justify;"><strong>Abstract</strong>:&nbsp; <strong>Objective</strong>:&nbsp; The&nbsp; objective&nbsp; of&nbsp; this&nbsp; study&nbsp; was&nbsp; to&nbsp; investigate&nbsp; the&nbsp; effects&nbsp; of electroacupuncture&nbsp; (EA)&nbsp; on&nbsp; endolymphatic&nbsp; hydrops&nbsp; (EH)&nbsp; and&nbsp; the&nbsp; regulation&nbsp; of&nbsp; Arginine vasopressin-aquaporin-2&nbsp; (AVP-AQP2)&nbsp; pathway&nbsp; in&nbsp; guinea&nbsp; pigs,&nbsp; so&nbsp; as&nbsp; to&nbsp; explore&nbsp; the&nbsp; possible mechanism of EA. <strong>Methods</strong>：&nbsp; EH was induced in male guinea pigs by an intraperitoneal injection of&nbsp; AVP.&nbsp; For&nbsp; the&nbsp; treatment,&nbsp; EA&nbsp; was&nbsp; delivered&nbsp; to&nbsp; “Baihui”&nbsp; (GV&nbsp; 20)&nbsp; and “Tinggong”&nbsp; (SI&nbsp; 19) acupoints, once per day for ten consecutive days. In histomorphological studies, cochlear hydrops degree was evaluated by hematoxylin-eosin (HE) staining, and then the ratio of scala media (SM) area&nbsp; to&nbsp; SM&nbsp; +&nbsp; scala&nbsp; vestibuli&nbsp; (SV)&nbsp; area&nbsp; (R&nbsp; value)&nbsp; was&nbsp; calculated.&nbsp; In&nbsp; mechanical&nbsp; studies,&nbsp; a comparison&nbsp; of&nbsp; plasma AVP&nbsp; (p-AVP)&nbsp; concentrations,&nbsp; cyclic&nbsp; adenosine&nbsp; monophosphate (cAMP) levels, vasopressin type 2 receptor (V2R) mRNA and AQP2 mRNA expression in the cochlea was made&nbsp; among&nbsp; groups.&nbsp; <strong>Results</strong>：EA&nbsp; significantly&nbsp; reduced&nbsp; cochlear&nbsp; hydrops&nbsp; in&nbsp; guinea&nbsp; pigs (P=0.001). EA significantly attenuated the AVP-induced up-regulation of p-AVP concentrations (P=0.006),&nbsp; cochlear&nbsp; cAMP&nbsp; levels&nbsp; (P=0.003)&nbsp; and AQP2&nbsp; mRNA&nbsp; expression&nbsp; (P=0.016),&nbsp; and&nbsp; upregulated the expression of V2R mRNA in the cochlea (P=0.004).&nbsp; <strong>Conclusion</strong>：These results suggest&nbsp; that&nbsp; dehydrating&nbsp; effect&nbsp; of&nbsp; EA&nbsp; might&nbsp; be&nbsp; associated&nbsp; with&nbsp; its&nbsp; inhibition&nbsp; of&nbsp; AVP-AQP2 pathway activation.&nbsp;</p><p style="text-align: justify;"><strong>Key words</strong>: endolymphatic hydrops,electroacupuncture,&nbsp; AVP-AQP2 pathway, Meniere’s disease</p><p><br/></p>