Expressions of neurotrophin factor receptor in spiral ganglion cell of cisplatin-induced ototoxicity / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To investigate the effects of high-affinity tyrosine kinase receptors TrkB, TrkC and the low-affinity neurotrophin receptor p75 in spiral ganglion cell (SGC) of cisplatin-induced ototoxicity.</p><p><b>METHODS</b>The 50 adult Wistar rats were divided randomly into 5 groups received intraperitoneal injection of cisplatin with vary dose. Control group was received equivalent volumes of saline. The group received 1 day intraperitoneal injection was cisplatin treated at a dose of 5 mg/kg and killed at next day. The group received 3 days was cisplatin treated for 3 days at same dose daily and then killed at next day. The group A received 5 days was cisplatin treated for 5 days and killed at next day. The group B received 5 days was cisplatin treated for 5 days and then were sacrificed after 7 days. The change of mRNA level of neurotrophin receptors in cochlear tissue were examined by RT-PCR. The expressing pattern of TrkB, TrkC, P75 in damaged cochlea were study by immunochemistry using antibodies against TrkB, TrkC, P75 protein.</p><p><b>RESULTS</b>The research data showed the expression of Trk B, Trk C, p75 exhibited in SGC was dynamic along with the administration lasting. The mRNA and protein level of Trk B (x(-) +/- s) at day 1 and 3 after cisplatin treatment were 0.76 +/- 0.06, 88.78 +/- 4.28, 0.82 +/- 0.09 and 91.64 +/- 4.06, with significant difference among those and other groups (P < 0.05). The mRNA and protein level of TrkC at day 1 after cisplatin treatment were 0.80 +/- 0.06 and 89.66 +/- 2.76, with significant difference among that and other groups (P < 0.05). The mRNA and protein level of p75 at the control group and cisplatin treated groups were 0.64 +/- 0.04, 55.16 +/- 3.10, 0.77 +/- 0.04, 78.46 +/- 3.86, 1.01 +/- 0.09, 105.02 +/- 6.61, 1.18 +/- 0.09, 111.10 +/- 6.08, 0.51 +/- 0.04 and 42.74 +/- 5.20, with significant difference among the control group and cisplatin treated groups (P < 0.05).</p><p><b>CONCLUSIONS</b>The expression of Trk B increased to peak at day 1 - 3 after cisplatin treatment and decreased at day 5 early and following weeks. The expression of Trk C went up to peak at day 1 after cisplatin treatment and went down during subsequently time. P75 kept a trend of continuance increased during the drug treatment and decrease at drug stopped. The expression of Trk B, Trk C and P75 may be involved in cochlear insult with cisplatin-induced. Trk B and Trk C may play an important role in the reparative process of cochlear, especially at early stage of the damage. P75 could promote SGC apoptosis in cisplatin-induced neurotoxicity.</p>

Expression of survivin and caspase-3 during the development process in rat cochlea / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To explore the role of some apoptosis regulators during the development in rat cochlea.</p><p><b>METHODS</b>The morphological development process of cochlea was observed in Wistar rat aged between embryo day 13 to postnatal day 14 in this experiment. Survivin and caspase-3 were respectively detected at protein and mRNA levels by immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>The expression of survivin and caspase-3 located in the bottom wall of the cochlear duct. Not only they widespread in the cell proliferation, but also they gradually enhanced in the cell differentiation. Both of them had a crest-time, and survivin was prior to caspase-3. In organ of corti during adult time, caspase-3 was not present and survivin was only expressed.</p><p><b>CONCLUSIONS</b>During the development of the rat cochlea, both of them had similar location and trend. But they were derangement. This showed that both of them participated in the cochlear morphological development. It was suggested that the interaction between survivin and caspase-3 regulated the apoptosis, promoted the cochlear morphological development.</p>