ABSTRACT
Objective To stud)' the expression of connexin (Cx) 26 and Cx30 in the cochlea in rat model of type 2 diabetes, and their role in the hearing loss of type 2 diabetes. Methods Sixty wistar rats were randomly divided into a control group(re = 20) and a experimental group(re = 4 0) . Rats in the experimental group received intraperitoneally injection of 10 mg/L streptozotocin to establish model of type 2 diabetes. Auditory brainstem response (ABR) was tested before and after molding at month 1, 2, 3, 4, 5. The morphology of cochlea was observed by HE staining, and the level and pattern of Cx26 and Cx30 expression within the cochlea were detected by immunofluorescence and Western blotting. Results In rats in the diabetes group, wave IH and V latency, I -IH and I - V interval of Click-ABRs (60 dBSPL) prolonged at month 1, 2, 3, 4, 5 after molding compared to the control (P < 0 . 0 5) . The number of cells was obvious reduced in the spiral ligament and ganglion of the experimental group (P < 0. 0 5) . Immunofluorescence and Western blotting results showed decreased expression of Cx26 and Cx30 in the experimental group at 2, 3, 4, 5 month(P<0. 05), and the expression of the two proteins decreased gradually with the time extension. Conclusion Expression of Cx26 and Cx30 is reduced at the same time as the occurrence of hearing impairment in rat cochlea with type 2 diabetes.