小脑顶核损毁对淋巴细胞功能的影响

EFFECT OF CEREBELLAR FASTIGIAL NUCLEUS LESIONS ON LYMPHOCYTE FUNCTION

目的:研究小脑顶核对淋巴细胞功能的调节作用,并初步探讨介导这种调节的中枢途径。方法:用海人酸(KA)毁损大鼠双侧小脑顶核,于术后第8d,取动物肠系膜淋巴结细胞和脾脏自然杀伤(NK)细胞进行体外培养,分别用四甲基偶氮唑(MTT)比色法检测由刀豆蛋白A(ConA)诱导的淋巴细胞的增殖反应,用流式细胞术测定NK细胞杀伤YAC-1肿瘤细胞的活性。同时用高效液相色谱法检测下丘脑中兴奋性神经递质谷氨酸的含量。结果:小脑双侧顶核注入KA后的第8d,小脑切片经Nissl染色,可见顶核内神经元胞体被有效破坏。此时,淋巴细胞对ConA诱导的增殖反应较双侧顶核注入生理盐水的对照组明显增强;而且NK细胞对YAC-1靶细胞的杀伤活性也明显高于对照组;同时下丘脑中谷氨酸含量较对照组明显减少。结论:小脑双侧顶核毁损可导致T和NK淋巴细胞功能明显增强,且下丘脑中谷氨酸含量显著下降,提示小脑顶核对淋巴细胞功能具有调节作用,小脑-下丘脑的谷氨酸能神经投射可能介导小脑顶核的免疫调节作用。

Aim： To investigate effect of cerebellar fastigial nuclei （FN）, one of three deep nuclei in cerebellum, on lymphocyte function, and possible central pathway involved in the effect. Methods： Kainic acid （KA） was microinjected into bilateral FN of rats. On the eighth day after the surgery, lymphocytes from the mesenteric lymph nodes were incubated to measure their proliferative reaction to concanavalin A （Con A） by means of colorimetric assay of methyl thiazole tetrazolium （MTT）, and natural killer （NK） cells from the spleen were cultured to evaluate their cytotoxicity to YAC-1 cells with the aid of flow cytometric assay. Simultaneously, glutamate content in the hypothalamus was determined by high performance liquid chromatography （HPLC）. As control, 0.9% saline was microinjected into the bilateral FN of rats. When these experiments ended, cerebellar sections and Nissl stain for each rat were made to observe the location and extent of the lesions. If the lesion areas were not in the bilateral FN or not limited in the FN, the results were discarded. Results： On day 8 following the KA injection of FN, the Nissl-stained cerebellar sections showed the neuronal bodies in the FN were effectively damaged by KA. Simultaneously, the lymphocyte proliferation induced by Con A was significantly increased and the NK cell cytotoxicity to YAC-1 target cells was remarkably enhanced when compared with those of the control animals microinjected with saline in their bilateral FN. At the same time as these changes of lymphocyte functions occurred, glutamate content in the hypothalamus was markedly reduced relative to that in the control hypothalamus. Conclusion： Effective lesions of cerebellar bilateral FN of rats can cause an enhancement of lymphocyte functions, including increase of proliferation of T cells and cytotoxicity of NK cells. The cerebellohypothalamic glutamatergic projections may be involved in the pathway of cerebellar FN immunomodulation.