双侧眼球摘除对大鼠视交叉上核的影响──免疫组化及光电镜体视学研究

采用双侧眼球摘除大鼠模型，术后存活不同时间，用免疫组化法探讨视交叉上核内ＶＩＰ和ＡＶＰ免疫反应强度和面积的变化；对变化明显的２１ｄ组进一步用光镜和电镜体现学方法进行形态学研究。＜１＞免疫组化研究：ＶＩＤ免疫染色，２１ｄ组免疫反应强度和面积均比对照组降低（Ｐ＜０．０５），２ｄ和７ｄ组免疫反应强度和面积与对照组相比无显著差异。ＡＶＰ免疫染色，三个时间实验组免疫反应强度和面积均与对照组无明显差异。＜２＞体视学研究：实验组ＶＩＰ样神经元胞体体积、胞核体积、核仁平均直径均明显缩小，粗面内质网和高尔基复合体表面积密度明显下降。以上所见提示摘除眼球２ｌｄ时，视交叉上核内直接接受光信息的ＶＩＰ样神经元的免疫活性下降是因阻断光传入所造成的。光传入的阻断和视神经纤维的溃变使视交叉上核中ＶＩＰ样神经元的结构呈现功能性改变，推测这些变化将引起该神经元肽类物质含量的下降。

THE INFLUENCE OF BILATERAL EYE ENUCLEATION ON THE SUPRACHIASMATIC NUCLEUS (SCN) IN RAT: IMMUNOHISTOCHEMICAL AND LM AND EM STEREOLOGICAL STUDY

The rats of bilateral eye enucleation were used in this study. The experiment animals were killed at different periods after enucleation. The VIP-immunoreactive intensities and areas in SCN were detected with immunohistochemical PAP tachnique. The experimental group which shown significant immunohistochemical changes was further studied morphometrically by LM and EM stereological method. The results were as follows: (1)Immunohistochemical study: The VIP-immunoreactive intensities and areas were reduced significantly in SCN of 21 st day experimental group. The immununoreactive intensities and areas of the 2nd day and 7th day experimental group were lower than the control group, but there was no significant difference between these two experimental groups and control group when the gray degree and areas were measured respectively. No singnificant difference was found when the AVP-immunoreactivity of each experimental group was compared with the control group. (2) LM and EM stereological study: The volume of VIP neuron soma. nuclei, and the diameter of nucleoli of the 21 st day group were smaller significantly compared with the control group by LM stereological method. The surface density of rough endoplasmic reticulum and Golgi complex in the VIP neurons of the 21 st day group was lower significantly than the control group with EM stereological method. These results showed that the functional activity of VIP nourons-the target neurons in the SCN receiving direct projection of light fiber from retina. was decreased at 21 st day after enucleation of eyes, but there was no significant changes of functional activity of AVP neurons which did not connect directly with the optic nerves. It indicates that the reduction of functional activily of VIP neurons is induced by the degeneration of optic nerve and interruption of light transmission after enucleation. The reduction of functional activity of VIP neurons at 21 st day after enucleation in this study and the increase of VIP immunoreactivity at 80th day after enucleation or keeping rats under dark environment reported in the literature may reflect the change pattern of suprachiasmatic nucleus at different period after treatment with different methods.