Reserch For Blocking NR2B Receptor Reversed The Process Of Cytotoxicity To Spiral Ganglion Neurons Induced By Sodium Salicylate In Guinea Pigs

Objective: To investigate whether blocking NR2B Receptor reversed theprocess of Cytotoxicity to Spiral Ganglion Neurons induced by sodiumsalicylate in Guinea Pigs by the method of applying Ifenprodil which is NR2Bantagonist at the round window niche. Methods: Sixty healthy guinea pigsprovided by the Experimental Animal Center of Guangxi Medical Universitywere randomly and evenly divided into a control group.control group(GroupI,no treatment), an APL group,(Group II,60μl APL directly applied to theround window),a sodium salicylate group (Group III,60μl APL directlyapplied to the round window and then be given intraperitoneal sodium salicylateinjection), and an ifenprodil group (Group IV,60μl of10μmol/l ifenprodil inAPL directly applied to the round window and then be given intraperitonealsodium salicylate injection). sodium salicylate was given at400mg·kg-1·d-1for7days. Auditory brainstem responses (ABRs) were recorded before animalsacrifice by decapitation. The left cochlea was removed and prepared fordetection of caspase-3expression in spiral ganglion neurons via immunohistochemistry. From each group,6cochleae were used to test apoptosisindex in spiral ganglion neurons using the TUNEL technique.Results: Beforesalicylate administration,the ABR threshold was less than40dB SPL in allanimals. After salicylate administration, the ABR threshold was33.33±5.17dBSPL in Group II,64.17±7.36dB SPL in Group III and49.17±5.85dB SPL inGroup IV, in contrast to31.67±5.16dB dB SPL in Group I (controls). Thecaspase-3expression not changed obviously in group I and Group II, but wassignificantly changed in Group III and Group IV (P<0.01). The caspase-3expression appeared to be decreased in Group IV compared to that in Groups III(P<0.05), but still increased compared to that in Group I and II (P<0.05). Theapoptosis index among spiral ganglion neurons in Groups III and IV increasedsignificantly compared to that in Group I and II (P<0.001). It is however, lowerin Group IV than in Group III (P<0.01).Conclusion: Blocking NR2B Receptorwith specificity can reverse the process of Cytotoxicity to Spiral GanglionNeurons induced by sodium salicylate in Guinea Pigs.