水杨酸钠引起耳鸣大鼠听皮层突触形态改变的透射电镜观察

目的用透射电镜观察水杨酸钠引起耳鸣大鼠听皮层突触形态的变化。方法成年健康雄性白色Wistar大鼠32只,随机平分为2组。第一组腹腔注射水杨酸钠350mg/kg,第二组腹腔注射等量生理盐水,均在每天上午9点注射,持续30天。两组所处饲养环境（包括环境噪声、12小时昼夜节律、饮食等）完全相同。1月后快速处死,取双侧听皮层组织进行透射电镜观察。结果与对照组相比,水杨酸组突触数量明显增加,许多突触形态由平型变成凹型或U型,突触界面曲率增加,突触面积增大,活性区增加,每一活性区的长度增加,突触间隙明显增宽,突触后膜致密物质厚度增加。U型突触直径平均为（1.7±0.23）μm,平直型突触直径平均为（0.53±0.14）μm,二者比较有显著性差异（P〈0.05）。结论水杨酸钠能够引起听皮层突触形态的改变,这种改变与长时程增强现象（Long-term potentiation,LTP）非常相似,有可能是耳鸣与突触可塑性以及与学习记忆相关的有力证据,值得深入研究。

Prolonged effects of salicylic acid on ultrastructure of auditory cortex synapses in a rat model of tinnitus

Objective To study prolonged effects of salicylic acid on the ultrastructure of synapses in the auditory cortex in a rat model of tinnitus. Methods Sixteen adult male white rats were randomly selected to be treated with peri toneal salicylic acid (300 mg/kg body weight) or with equivalent volume of normal saline for 30 days. Animals in both groups were maintained under the same conditions. Synapses in the auditory cortex were studied under a transmission electron microscope. Results Compared to the control group, salicylic acid treated animals showed increased number of synapses with wideer clefts, thicker postsynaptic densities, longer active zones, and increased synaptic interface curvature (p < 0.05). Conclusion The results suggest that Salicylic acid induce changes of synapses in rats. Such changes corre late to long-term potentiation (LTP) following intensive stimulation The results provide a strong evidence for the relation between tinnitus and learning and memory.