GLIAL CELL LINE-DERIVED NEUROTROPHIC FACTOR AND NEUROTROPHIN-3 PROTECT HAIR CELLS FROM INJURY OF EXPOSURE TO TRAUMATIC NOISE: OBSERVATION OF THE NUCLEAR MORPHOLOGY / 解放军医学杂志

ABSTRACT

This study was aimed at to investigating the protective effect of a combined treatment with glial cell line derived neurotrophic factor (GDNF) and neurotrophin 3 (NT 3) on noise induced outer hair cell (OHC) damage. Guinea pigs were subjected to receiving infusion of an artificial perilymph containing GDNF (100ng/ml) and NT 3 (2 5?g/ml) into one cochlea via a mini osmotic pump. Three days later, the animals were exposed to a 4kHz narrow band noise at 115 dB SPL for 4h. The control animals received the same treatment except GDNF and NT 3. Thresholds of auditory brainstem responses (ABRs), elicited by clicks, were measured before and 3 days after the surgery of the pump implantation, and 10 days following noise exposure. Then, the subjects were sacrificed and the cochleas were stained with Hoechst 33342. The specimens were examined under a fluorescence microscope for quantitative assessment of the OHC nuclear morphology. The results showed that compared with the control animals, the drug treated ones had significant less swollen OHC nuclei ( P