The Signal Transduction Of The Rat Vestibular Epithelium In Vitro

Sensory hair cells are involved in the detection of sound, linear and angular acceleration, and substrate vibration. Sound is transduced by hair cells in the cochlea, and movements of the head are transduced by hair cells in vestibular.Hair cells are damaged by disease,exposure to loud sound,treatment with ototoxic drugs,and processes associated with aging.lt has been suggested that mature mammals may also have a limimed capacity for hair cell regeneration in their vestibular sensory epithelia.The specific factors that regulate the proliferation of cells in the sensory epithelia of the inner ear have not been conclusively identified. To determine the mechanism of signal transduction involved in the apoptosis and regeneration of vestibular hair cells of mammals will provide reliable theoretical evidences for therapy of the vestibular deseases as well as cochlear deseases in the future.AimTo establish a kind of culture system of vestibular epithelium of rat in vitro,a new realm is provided to study the changes of the expression of PKC P i(protein kinase C), PKC P 2 and PKC y and ERK2(extracelluar signal ragulated kinase-2) of vestibular end organ were observed, cell proliferation was detected by Brdu (bromodeoxyuridine) immunocytochemistry. Method1 .The vestibular culture system was established by organ culture method.2.The expression and location of PKC PI, PKC ? and PKC Yin vestibular organs was detected by immunohistochemistry after PMA(phorbol 12-myristate 13-acetate) induced.3.The expression and location of ERK2 in vestibular organ was detected by immunohistochemistry after PMA induced.4.The cell proliferation was detected by anti-Brdu immunohistochemical method after PMA induced.Result1. The stain of PKC isoforms ?i, &&nd Y was weak innormal culture group. The antigen distributions of different PKC isoforms were different. Comparied with control group, In the experimental groups, PKC levels were elevated significantly and increased to its maximum at 30 minutes. At 45 minutes still to increase than normal. PKC 3 staining detected in cell membrane, PKC P 2, not only stained in cell membrane but in cilia, PKC Y staining detected increased hi cell cytoplasm .2. The expression of ERK2 was detected in vestibular epithelium. Its expression was weaker in cytoplasm. It was increased in nucleus and cytoplasm after PMA induced in vitro. In each group the expression style was similar among the utricle hair cell layer and suppering cell layer.3. There were little Brdu positive cells hi control group.After PMA induced in vitro, the Brdu positive cells were increased, a large number of positive cells was seen. The positive cells predominantly located hi hair cell layer and supper cell layer.Conclusion1 .Organ culture refer to the culturing of dispersed cells or undissociated tissue fragments,It maintains the structureal integrity of the original tissue,and thus preserves the normal cellular interactions. This technique offers important advantages for studying mammalian hair cells regeneration,Organ culture techniques have become basic to most area of medicine and the biological sciences.2.There were some changes of PKC expressions activity in vestibular terminal organs of rat after PMA induced in vitro, the expression of different PKC isoforms were different.lt suggests PKC may play a significant role in signal tranduction process of vestibule epithelium and different PKC isoforms may perform different physiological functions respectively.3.After PMA induced in vitro, the expression of ERX2 changed indicating they involve in the proliferation of vestibular cells ,PKC and MAPK (mitogen activated protein kinase) may be important in proliferation/ differentiation of hair cells of inner ear.