Cellular And Subcellular Expressions Of Gap Junction Cx26 And Cx30 In The Mammalian Cochlea

Object: To study the expressions and cellular distributions of Cx26 and Cx30 in the cochlea lateral wall in different mammalian cochlea.Methods: We used double immunofluorescent staining and confocal microscopy to examine the expressions and cellular distributions of Cx26 and Cx30 in the stria vascularis (SV) and spiral ligament (SPL) in the cochlear lateral wall of rats,mice and guinea pigs.Results: By using specific cell marker (Kir4.1), we have firstly found that the intermediate cell has strong expressions of Cx26 and Cx30. Cx26 and Cx30 labeling appeared to be irregular and leaf-like in the intermediate cell. However, Cx26 and Cx30 in the basal cell layer showed intense labeling surrounding the basal cells, demonstrating a hexagonal distribution pattern. In the dissociated-cell preparation, Cx26 and Cx30 have labeling at the basal cell and the intermediate cell. The marginal cells were negative to Cx26 and Cx30 labeling. Cx26 and Cx30 in SPL showed a different pattern. The labeled puncta were distributed vertical to the long axis of the SPL. Cx26 labeling was intense at the edge region of the SPL and little at the middle region. Cx30 had intense labeling at the middle region in SPL.Conclusion: The data demonstrate that Cx26 and Cx30 in the SV and SPL have distinct, cell-specific expressions, implying that they achieve different functions in the cochlear lateral wall. Object: Quantitatively analysed the expressions of Cx26 and Cx30 proteins in the cochlear lateral wall.Methods: First, using Western Blot to examine the expressions of Cx26 and Cx30 in the SV and SPL, and in the apical and basal turns in the cochlear lateral wall in different species (mice, rats, and guinea pigs). Second, using RT-PCR to analyse the expressions of mRNA of Cx26 and Cx30 in the SV and SPL in the cochlear lateral wall of rats,mice and guinea pigs.Results: From Western-blot of SV and SPL, we found that the expressions of Cx26 and Cx30 in the SPL were higher than in the SV. The level of Cx26 protein in SPL was 5.1958,1.7708 and 1.7570 fold higher than in SV in guinea pigs, rats and mice respectively. There was a statistically significant difference among different species (P < 0.05, ANOVA). However, Cx30 protein level of SPL was 4.2973,3.6205 and 3.5554 fold compare to that of SV in guinea pigs, rats and mice, respectively. These was no statistically significant difference among different species(P >0.05,ANOVA). The analysis of Cx26 and Cx30 protein expressions in different turns indicated that there was no a significant difference between the apical and basal turns. We also found that the mRNA of Cx26 and Cx30 in the SPL of mice were higher than in the SV, the ratios between SPL to SV for Cx26 and Cx30 were 1.8812 and 1.1643, respectively.Conclusion: Our date indicate that the expressions of Cx26 and Cx30 in SPL are higher than those in the SV at mRNA and protein levels. The data also reveal that the expressions of Cx26 and Cx30 in the cochlea have differently expressive levels in different species. Objective: To study the expressions of Cx26, Cx30 and ZO-1 and relationship in the cochlear sensory epithelium.Methods: In this study, we used double immunofluorescent staining and confocal microscopy to examine the distrubutions Cx26, Cx30 and ZO-1 and relationship in the cochlear sensory epithelium.Results: Cx26 and Cx30 were both expressed in Hensen cell, inner and outer pillar cell and Claudius cell. Cx26 labeling largely overlapped that of Cx30 in these regions. Cx26 and Cx30 were also coexpressed in the spiral limbus. Neither Cx26 nor Cx30 labeling was seen in the hair cells. The expressions of Cx26 and ZO1 demonstrated distinct expressions between the surface layer and the deep layer in the cochlear sensory epithelium. In the surface layer of cochlear sensory epithelium, ZO1-positive labling was mainly localized between senseory hair cells and suporting cells, there were fewer or no Cx26-postive spots. In the deep layer of cochlear sensory epithelium, Cx26 was widely expressed. However, ZO1 staining was undetectable.Conclusion: ZO1 and Cx26 expressions in the sensory epithelium have different location and were not overlapped. Tight junctions maintain the ion barrier between the endolymph and perilymph,and gap junctions take part in ion transportation.