A New Cell Type In Rat Organ Of Corti After Aminoglycoside Insult

Objective: Comparative and extended research among the newly found cell, microglia cell and atypical cell in the rat organ of Corti after aminoglycoside intoxication; to further explore quality, origin, and the relationship between the newly found cell and the neural stem cell or nestin(+) progenitor cell.Methods: Study the newly found cell with the weak silver carbonate staining method of del Rio-Hortega. Using transmission electron microscopy, compare the newly found cell with the atypical cell found by Marc Lenoir and Philippe Vago, and extend young SD rat model to adult SD rat, young and adult Wistar rat,and extend drug of Neomycin to Amikacin to study the universality. Examine the expression of nestin(+) protein in the rat organ of Corti by the technique of RT-PCR to explore the relationship between the newly found cell and the neural stem cell or nestin(+) progenitor cell.Results: As positive control, in the rat brain cortex microglia cells could be stained clearly while no cell with the same staining result could be found in the rat organ of Corti. The newly found cell has been found in whatever young or adult, SD or Winstar rat, using whatever Neomycin or Amikacin. No difference of the newly found cell had been found among these groups, while distinct difference existed in the ultrastructure between the newly found cell and atypical cell. The expression of nestin (+) protein which is the mark of neural stem cells had been found in SD rat organ of Corti on postnatal day 16 in aminoglycoside group, while no expression on the same day in normal group.Conclusions: Regarding to our previous work of immunohistochemistry negative staining result of Leukocyte common antigen, the newly found cell is neither likely microglia cell, nor the atypical cell. The appearance of it is not completely related to the degree of maturity of the organ of Corti and SD rat, which suggests that it may have a degree of representative. The earliest time it appears is the 4th day during drug injection in young rat. It is not an apoptotic cell was supported again. It should be distinguished from the other high electron dense cells in the organ of Corti in morphology. It may derive from neural stem cell or nestin (+) progenitor cell, and Regarding to our previous work of labeling proliferating cells by Brdu, a mitotic process or a direct transdifferentiation may be involved in the generative mechanism.