Expression And Significance Of Cx29 And Cx30 In Cochlea Of Postnatal Rat At Different Developmental Stages

Objective:To study the expression of connexin29 and connexin30 in cochlea of postnatal rat at diverse developmental periods,and the correlation with auditory brainstem response (ABR).Then to explore the role of connexin29 and connexin30 during development in the hearing.Methods:The rats were divided into three groups (plw, p3w and p9w) as different developmental periods.The auditory brainstem response of rats in each group were tested respectively.The cochleas of rats in each group were taken out immediately after they were under anesthetic.Decalcification was performed and the expression of connexin29 and connexin30 were examined by using the technique of immunohistochemistry in paraffin section of the cochleas.The images of the stained section of cochleas in each group were analyzed lastly.Results:1 Plw rat did not show ABR wave,and there was significant difference in the ABR threshold between P3w and P9w rat.2 Strong immunorespectivity could be observed for Cx29 in the cochleas in each group.The immunostaining for Cx29 was mainly located in stria vascularis,spiral ligament,spiral ganglion cell, spiral limbus,and weak staining could be found between supporting cells of the organ of Corti.3 Immunostaining for Cx30 was much weaker than Cx29 in the cochleas of the rats in each group.The immunostaining for Cx30 was mainly located in stria vascularis,spiral ligament,spiral limbus, supporting cells of the organ of Corti,and weak staining could be observed in the spiral ganglion cells.There was no immunostaining for Cx30 in supporting cells of the organ of Corti of Plw rat.4 The analysis of average integral optical density value of Cx29:the immuno-staining for Cx29 in spiral ganglion cells was much stronger than other parts.There was statistical significance between Plw and P3w (P<0.05),Plw and P9w (P<0.05) in the regions,but the difference between P3w and P9w was not significant (P>0.05).5 The analysis of average integral optical density value of Cx30:the immuno-staining for Cx29 in each group was weaker than Cx29.There was statistical significance between Plw and P3w (P<0.05),Plw and P9w (P<0.05) in the regions, but the difference between P3w and P9w was not significant (P>0.05)Conclusions:1 The different expression of Cx29 and Cx30 in cochleas of postnatal rats at different developmental stages may be involved in the development of cochlea function,and may have a close relationship with the mutaration of cochlea.They are the basic structures to preserve the morphology of the cochlea.2 Cx29 and Cx30 could be parts of the cochlea neuron and the basic structures to generate the action potential,which will promote the mutaration of cochlea.3 the deletion and variation of Cx29 and Cx30 may be in relation to deafness.