OBJECTIVETo investigate the effects of erlong zuoci (ELZC) pills and its disassembled prescriptions (Shudi-huang-Zexie group and Zexie group) on the enzymatic activity and protein expression changes of the key apoptosis molecules in the gentamycin injured hair cells.

METHODThe model of gentamycin induced ototoxicity in mice cochlear primary cultures was copied. Cochlear organotypic cultures of postnatal day 3-5 (P3-P5) mice were treated with gentamycin alone or in combination with ELZC pills, Shudihuang-Zexie group or Zexie group respectively. The enzymatic activity of Caspase-9 and Caspase-3 was determined by means of fluorescence staining in situ. The protein expression of Bcl-2 and Bax in the hair cell area was examined by immunofluorescence in normal and treated specimens.

RESULTAverage optical density analysis indicated that, compared to the normal group, 0.03 mmol x L(-1) gentamycin could significantly activate Caspase-9 and Caspase-3, downregulate the ratio of Bcl-2 and Bax protein expression. Compared to the gentamycin model group, ELZC pills significantly inhibited the enzymatic activity of Caspase-9 and upregulated the ratio of Bcl-2 and Bax protein expression, showing inhibition trend toward the enzymatic activity of Caspase-3. Both Shudihuang-Zexie group and Zexie group could effectively inhibit the enzymatic activity of Caspase-9 and Caspase-3, upregulate the ratio of Bcl-2 and Bax protein expression.

CONCLUSIONELZC pills, Shudihuang-Zexie group and Zexie group can effectively protect hair cells from gentamycin by correcting the abnormal changes of the mitochondrion-dependent signal transduction pathway.