Ligustrazine fought against cisplatin induced ototoxicity in guinea pigs / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To study the protective effect of Ligustrazine Injection (LI) against cisplatin-induced ototoxicity and to explore its mechanism.</p><p><b>METHODS</b>Thirty healthy adult guinea pigs were randomly divided into three groups, 10 in each group, i.e., the normal control group, the cisplatin group, and the LI group. Guinea pigs in the normal control group were intraperitoneally injected with normal saline at 3 mL/kg for 7 consecutive days. Those in the cisplatin group were intraperitoneally injected with cisplatin at 3 mg/kg for 7 consecutive days. Those in the LI group were intraperitoneally injected with LI at 140 mg/kg for 7 days, but cisplatin (3 mg/kg) was intraperitoneally injected from the opposite side starting from the 4th day. Brainstem auditory evoked potential (BAEP) was performed in all animals before and after injection. All animals were sacrificed after the final testing under anesthesia and their cochleas collected. Half the cochleas of each group were collected for silver nitrate staining of cochlear basilar membrane stretched. The other half the cochleas of each group made into paraffin sections to observe the apoptosis of cochlea cells by TUNEL method and the expression levels of c-Jun detected by immunohistochemistry.</p><p><b>RESULTS</b>There was no statistical difference in the difference of BAEP threshold among the 3 groups before injection (P > 0.05), but the BAEP threshold increased in the cisplatin group and the LI group (P < 0.05). Besides, it was higher in the cisplatin group (P < 0.05). In the cisplatin group, most hair cells were missing, spiral ganglion cells obviously decreased, more TUNEL positive cells occurred, and the expression of c-Jun was stronger. But the aforesaid impairment in the LI group was obviously lessened (P < 0.05).</p><p><b>CONCLUSIONS</b>LI showed certain antagonist effect on cisplatin-induced ototoxicity. Its mechanism might be associated with scavenging oxygen radicals of the cochlea tissue, improving the microcirculation, and fighting against apoptosis.</p>

Preventive effects of cerebro cellular growth peptide on gentamycin-induced inner ear damage in guinea pigs / 中国应用生理学杂志

<p><b>AIM</b>To investigate the preventive effects of the cerebro cellular growth peptide (CCGP) on gentamycin-induced inner ear damage in guinea pigs, and to clarify its mechanism.</p><p><b>METHODS</b>The hypoacusis severity and enzymatic activity in the cochlear hair cells were examined by brainstem auditory evoked potential (BAEP) and histochemistry, respectively. The damaged hair cells was counted in three groups.</p><p><b>RESULTS</b>CCGP reduced the elevated BAEP reaction thresholds. It protected activities of mitochondrial succinate dehydrogenase and lysosome acid phosphatase in the cochlear hair cells. The number of damaged hair cells in the CCGP group was less than that in the gentamycin (GM) group.</p><p><b>CONCLUSION</b>CCGP can reduce GM ototoxicity. The mechanism may be associated with the protective activity of mitochondrial enzyme, the maintenance of lysosome intactness, energy metabolism of the cochlear hair cells, and reduction of autolysis of hair cells induced by hydrolase over flowing from lysosome.</p>