大鼠中枢神经系统内IgG免疫反应阳性细胞的分布

The Distribution of IgG Immunoreactive Cells in the Rat Central Nervous System

用免疫细胞化学法研究ＩｇＧ样免疫反应（ＩｇＧ－ＧＩＲ）细胞在正常成年大鼠中枢神经系统（ＣＮＳ）内的分布。内源性ＩｇＧ可出现在软脑膜，穿通血管、室管膜、下丘脑和最后区等室周器官。在脊髓前角运动神经元（Ｍｎ）和第Ⅲ、Ⅳ、Ⅴ、Ⅵ、Ⅹ、Ⅻ颅神经运动神经元及疑核细胞呈现ＩｇＧ－ＩＲ，视上核和室旁核呈现ＩｇＧ－ＩＲ，小脑的普肯野氏细胞、颗粒层和小脑深核的一些细胞存在阳性染色，大脑皮质的Ⅲ～Ⅴ层和海马常有阳性细胞，偶见胼胝体等处呈现阳性胶质细胞。切断神经可阻断运动神经元的ＩｇＧ积累并使相应Ｍｎ细胞周边出现ＩｇＧ－ＩＲ。实验结果提示，ＣＮＳ提取ＩｇＧ可能与ＣＮＳ—体液免疫反应调节和ＣＮＳ损伤有关。

The distribution of IgG immunoreactivity(IgG-IR) was studied with ABC method(antimouse IgG Vectastain Kit from Vector Lab) in the central nervous system(CNS)of normal adult rat.The endogenous IgGs were revealed immunocytochemically in the piamater and pial vasculature,the ependyma,and diffusely in the hypothalamus and area postrema where the blood-brain barrier(BBB)is permeable to plasma proteins.Intraneuronal IgG-IR presented in the ventral horn motor neurons of the spinal cord at all levels,motor neurons of cranial nerve Ⅲ,Ⅳ,Ⅴ,Ⅶ,Ⅹ and Ⅻ,and some cells of the nucleus ambiguus.Intracellular labelling could be noted in the supraoptic nucleus and the paraventricular nucleus.Purkinje cells, some cells of the granular layer and the deep nucleus in the cerebellum were positively stained. IgG-IR neurons were also observed mainly in the layers Ⅲ-Ⅴof the motor-sensory cortex and in the hippocampus. Occasional staining of glia cells was noted such as in corpus callosum,The accumulation of IgGs in motoneurons of L3-5 and cranial nerve Ⅻ was respectively prevented by axotomy of the sciatic nerve and hypoglossal nerve. Our experiments support the hypothesis that spinal cord and brain stem neurons take up immunoglobulins by their axon projecting outside BBB. A series of anterograde and retrograde transneuronal transfers are responsible for the intraneuronal labelling in relay nuclei and in other CNS neurons.The lgG from CSF may be also a sourse of positive labellings.The function of physiologically accumulating IgG by neural cells is not known, but it may have important significance in manipulating humoral immune reaction by CNS and immune lesion in CNS.