Age-related Expression Of Plasma Membrane Ca²⁺-atpase Isoform2in The Cochlea Of C57Bl/6J Mice

Objective To investigate the location and distribution of plasma membrane Ca2+-ATPase isoform2(PMCA2) in the cochlea of C57BL/6J mice at various age(4w,14w,22w,45w),and to reveal the relationship of PMCA2and age-related hearing loss (AHL).Methods The distribution of PMCA2in the cochlea of C57BL/6J mice was detected by immunohistochemistry at various ages (4w,14w,22w,45w). Real-time polymerase chain reaction (Rt-PCR) was used to detect the level of PMCA2mRNA in the cochlea of C57BL/6J mice at the ages of4,14,22and45weeks old respectively.Results PMCA2was mainly located in the hear cell, stria vascularis, and spiral ganglion cells. Faint labeling of PMCA2was also observed in spiral ligament. Hair cells lodged or missed, the number of spiral ganglion cells reduced and stria vascularis atrophied with age. Expression of PMCA2in the cochlea of C57BL/6J mice also showed age-related decreasing. The results of Rt-PCR demonstrated the expression of mRNA of gene (Atp2b2) at45weeks age was significantly less than4week-old mice cochlear(P<0.05).Conclusion PMCA2was mainly located in the the hear cell, stria vascularis, and spiral ganglion cells. Faint labeling of PMCA2was also observed in spiral ligament.The expression of PMCA2demonstrated an age-related decrease with age. The mRNA expression level of PMCA2gene (Atp2b2) in the cochlea of C57BL/6J mice displayed an age-related decrease. PMCA2transporters may play a critical role in maintaining the normal morphology of the inner ear and it may be related to AHL.