Endoplasmic reticulum molecular chaperone involved in the impairment of inner ear consistented with the mimetic aging rats / 临床耳鼻咽喉头颈外科杂志

ABSTRACT

Objective:To explore the involvement of endoplasmic reticulum molecular chaperone GRP78 in the impairment of inner ear consistented with the mimetic aging model.Method:Twenty-four Wistar rats were randomly divided into two groups. model group was in duced by daily hypodermic injection of 10% D-galactose (800 mg·kg~(-1)·d~(-1)) for 8 weeks and the control group was given saline accordingly. Spatial learning and memory was measured by Morris-Water-Maze. Colorimetry was used to analyze superoxide dismutase (SOD) and malondialdehyde (MDA) extracted from inner ear tissue. Hearing threshold of rats were detected with Auditory brainstem response (ABR).In addition, expression of GRP78 in the inner ear was detected by immunohistochemistry,RT-PCR and Western blot. The control group was studied parallel.Result:The escape latency in the model group injected with D-galactose was markedly longer than that in the control group.accordingly ,the changes of SOD and MDA were more significant in the model group, the difference between two groups was significant(t-test,P0.05). The expression of GRP78 was significantly different between two groups ,which is increased in the inner ear tissue of model group(P<0.01).Conclusion:The impairment of inner ear tissue partly dued to the oxidative stress in the model, which was induced by D-galactose.and endoplasmic reticulum molecular chaperone was thought to contribute to the impairment mechanism of inner ear in mimetic aging model.