Localization And Expression Of Osbpl2 Gene In Hyperlipemia Mouse Cochlea

Objective:OSBP-like (OSBPL) or OSBP-related (ORP) proteins are homologues of Oxysterol-binding protein (OSBP), they constitute a conserved family in eukaryotes from yeast to human. ORPs are implicated in many cellular processes including cell signaling, vesicular trafficking, lipid metabolism, and nonvesicular sterol transport. The aim of this study is to illuminate the localization and expression of Osbpl2 in mouse cochlea and its potential effects on hearing loss of hyperlipemia mouse.Methods:Sixty-five mice were fed with either hyperlipemia diet or normal diet for 8 weeks. Hyperlipemia model was established in forty mice, and the other 25 mice were served as normal control. The tone-burst auditory brainstem response (ABR) threshold test and lipid measurement were conducted for both normal control and hyperlipemia mice. Immunohistochemical analysis and scanning electron microscopy for mouse cochlea were performed. Furthermore, semi-quantitative real-time PCR assay was used to show the expression of Osbpl2 gene in mouse corti and other main tissues.Results:Osbpl2 in mouse cochlea was localized at multiple structures in the specific area of the mouse cochlea, such as corti, stria vascularis and spiral ganglion. In mice with hyperlipemia, the expression of Osbpl2 gene in cochlea as well as many other tissues was reduced as showed in immunohistochemical analysis and semi-quantitative real-time PCR assay. ABR test showed increased threshold level of mice after intervention of hyperlipemia diet, meanwhile, the degeneration of hair cells in corti was observed via scanning electron microscopy in hyperlipemia mice.Conclusions:Osbpl2 is widely expressed in mouse cochlea. Intervention of hyperlipemia diet can damage the mouse hair cells and lead to hearing loss that was probably related to the down-regulation of Osbpl2 gene.