白噪声对豚鼠耳蜗核一氧化氮合酶活性的影响

The effect of white noise on activity of nitric oxide synthase in cochlear nuclei of guinea pigs

采用硫辛酰胺脱氨酶组织化学方法及图象分析技术，研究白噪声暴露后豚鼠耳蜗核一氧化氮合酶（NOS）神经元及NOS活性的变化与听阈的关系，探讨豚鼠耳蜗核NOS神经元在白噪声损伤过程中可能的作用。结果表明，白噪声暴露后耳蜗核NOS阳性神经元的数量及染色强度明显增加，2周达到高峰，3～4周持续高表达，至5周有所恢复，仍高于正常水平。白噪声暴露后7d以内，耳蜗核NOS活性与ABR阈值有分离现象，7d后，NOS活性与ABR阈值呈正相关（r＝0．9571，P＜0．01）。结果提示，白噪声暴露后，耳蜗核NOS可能具有多重作用，NOS活性在一定范围内可能促进损伤修复，过量表达可加重耳蜗神经损伤。

This experiment adopted lipoic amido dehydrogenase (NADPH-d) histochemistrymethod and image pattern analysis technique to investigate the relationship between nitric oxidesynthase (NOS) neurons and activity of NOS and auditory threshold, and to explore the possiblerole of NOS neurone in cochlear nuclei of guinea pigs after exposed to white noise. The resultsshowed that the quantity and staining intensity of positive NOS neurons in cochlear nuclei increasedobviously after exposed to noise. It reached the peak 2 weeks later and remained high expressionduring 3-4 weeks. It restored 5 weeks later but was still higher than normal. Within 7 days afterexposed to noise, activity of NOS in cochlear nuclei deviated from ABR threshold. After 7 days,activity of NOS had a positive correlation with ABR threshold (r =0. 9571, P <0.01). It is sug-gested that NOS in cochlear nuclei might play double role after exposed to white noise. On onehand, a certain range of acitivity of NOS might help to restore injured neurons. On the otherhand, over expression of NOS might exacerbate the injury of cochlear nerves.