Techniques for isolating hair cells from guinea pig cochlea.

Isolated live hair cells are important models for studies on the electrophysiology, pathology and pharmacology of the hair cell. Using mechanical isolation method after papain treatment, 70 +/- 27 hair cells, including 0 to 4 inner hair cells, could be obtained from each cochlea of 4 guinea pigs. The criteria for a good viability of isolated cochlear hair cells were: 1) a smooth hair cell membrane; 2) hair cells not swollen; 3) the nucleus in normal position; 4) the cytoplasm in a state of translucence with a halo at the periphery (birefringence); and 5) no Brownian movement of the organelles within the cytoplasm. With short-term culturing at room temperature, approximately 90% of the isolated hair cells retained a good viability at the end of two hours. Subsequently, the hair cells gradually degenerated but still, at the end of five hours, about 40% of them appeared intact. The degeneration patterns have been carefully observed and described.