不同浓度阿霉素影响大鼠三叉神经痛模型超微结构及行为学研究

INFLUENCES OF DIFFERENT CONCENTRATIONS OF DOXORUBICIN ON TRIGEMINAL NEURALGIA ULTRASTRUCTURE AND BEHAVIORS IN RATS

目的:本实验是在建立改良的大鼠三叉神经疼痛模型(颧骨下入路)基础上,通过眶下神经周围(眶下孔)注射两种不同浓度的阿霉素,比较大鼠的行为学变化及对三叉神经节超微结构影响,从微观角度验证阿霉素治疗三叉神经痛的有效性及其机制。方法:建立实验鼠上颌神经分支即眶下神经慢性缩窄环术(infraorbital nerve,chronic constriction injury,ION-CCI)模型,在该三叉神经痛模型成功建立的基础上,挑选出现三叉神经痛样反应的雄性SD大鼠60只,随机分成生理盐水组(A组),无水酒精组(B组),0.33%阿霉素组(C组),0.75%阿霉素组(D组),四组分别于注射前,注射后10 d、20 d、30 d的观察大鼠痛反应阈值,并在各时间点随机抽取3只大鼠观察三叉神经节做超微结的变化。结果:1行为学变化:0.75%阿霉素组注射后10 d可见痛阈值明显上升,并持续至注射后30 d,与其他三组比较有显著差异(P<0.01);其余三组注射前后各时间点无统计学差异。2三叉神经节超微结构的改变:D组在注射后10 d可见神经节细胞明显水肿,以线粒体和内质网为主要病理学改变;注射30 d时可见神经节细胞核固缩、崩解,细胞器消失,部分细胞轻度水肿。A、B、C、D四组在注射前神经节细胞核及细胞器无明显改变;A、B、C三组在注射前与注射后各时间点比较,神经节细胞核及细胞器均无显著改变。结论:1阿霉素能通过逆轴浆运输机制,靶向破坏三叉神经半月节,从而起到镇痛的效果;2在本次实验中,0.75%阿霉素比0.33%阿霉素在抑制大鼠三叉神经疼痛方面起到较好的疗效,且未见明显副作用。

Objective： In this work, two concentrations of doxorubicin were injected through suborbital nerves in the rat of established trigeminal neuralgia model（zygomatic approach） to investigate behavior changes and corresponding impact on the ultrastructure of trigeminal ganglion, so as to probe the effectiveness and mechanisms of doxorubicin treatment for trigeminal neuralgia from a microscopic view. Methods： A chronic constriction injury（CCI） model for the infraorbital nerve（ION）—branch of trigeminal nerve of rat was set up. On the basis of the successful set-up of trigeminal neuralgia model, 60 male SD rats with trigeminal neuralgia symptom were divided randomly into normal saline group（Group A）, anhydrous alcohol group（Group B）, 0.33% adriamycin group（Group C）, and 0.75% adriamycin group（Group D）, which were tested for threshold trigeminal neuralgia values at 10 d, 20 d, and 30 d after injection, and ultrastructural changes of trigeminal ganglia was examined with 3 randomly selected rats at every time points, respectively. Results： 1 Behavioral changes： Threshold trigeminal neuralgia values for the 0.75% adriamycin group, was significantly elevated at 10 d after the injection, which lasted for 30 d, compared with the other three groups（P 0.01）. No statistical significance were observed for the other three groups at none of the chosen time points before and after the injection. 2 Changes of ultrastructure of trigeminal ganglia： ganglion cell edema was visible in 10 d after the injection, with mitochondria and endoplasmic reticulum network as the main sties of pathological changes; while 30 d after the injection, ganglion cell nucleus pycnosis, disintegration, and vanishing of cell organelles, as well as mild edema appeared in a portion of cells. Prior to injection, no visible changes occur to ganglion cell nucleus and organelles for Group A, B, C, and D; while for Group A, B, and C, no significant changes occur to ganglion cell nucleus and organelles at all time points before and after the injection. Conclusion： 1doxorubicin can target semilunar ganglion through retrograding axoplasmic transport mechanisms to confer analgesic effect; 2 in this experiment, 0.75% rather than 0.33% adriamycin doxorubicin can effectively inhibit rat trigeminal nerve pain, with no significant side effect.