结肠扩张刺激对P2X4受体在IBS大鼠神经中枢中表达的影响

Effects of expressions of P2X4 receptor in nerve center induced by the stimulation of colorectal distention in rats with irritable bowel syndrome

目的观察P2X4受体在结肠扩张刺激引起的IBS大鼠骶髓后连合核(DCN)和骶髓后角中表达的变化,为探讨IBS的神经作用机制提供理论依据。方法采用免疫组织荧光化学的方法,通过对P2X4受体和小胶质细胞的标志物OX42的荧光双标记,观察其在小胶质细胞和神经元上的反应;通过免疫电镜同步观察P2X4受体与小胶质细胞和神经元的相互关系。结果对照组大鼠的DCN和骶髓后角中几乎没有发现P2X4的表达。而在IBS大鼠组,P2X4在DCN和骶髓后角神经元和小胶质细胞中表达明显增高。电镜下,在对照组的DCN和骶髓后角,少数P2X4-LI产物表达在胶质细胞突起上,此突起可与神经元胞体、轴突、树突或另外的胶质细胞突起接触。而在IBS大鼠的DCN和骶髓后角中,P2X4在抑制性突触上的表达明显增加。有的表达在突触复合体上,并且在神经元上也有发现。然而P2X4阳性产物更多的表达在胶质细胞的突起上。结论P2X4是小胶质细胞活化的启动因素,可能是IBS内脏敏感性增高的重要因素。

Objective To observe the expressions of P2X4 receptor in dorsal commissural nucleus （DCN） and dorsal horn of the sacral segment of spinal cord in rats with irritable bowel syndrome （IBS） induced by the stimulation of colorectal distention, and to provide theory evidence for the prevention and cure of irritable bowel syndrome. Methods By using the immunofluorescent double staining method, to observe the expressions of P2X4 receptor in neurons and microglia cells of DCN and dorsal horn of the sacral segment of spinal cord in rats with IBS. By immunoelectron microscope to detect the relationship of P2X4 receptor between the neurons and mieroglia cells of DCN and dorsal horn of the sacral segment of spinal cord in rats with IBS. Results There were hardly any expressions of P2X4 receptor in DCN and dorsal horn of the sacral segment of spinal cord in control group. The expressions of P2X4 receptor in DCN and dorsal horn of the sacral segment of spinal cord in rats with IBS were significantly up-regulated than control group. Under immunoelectron microscope, a few positive substance of P2X4 receptor expressed in apophysis of mieroglia cells in DCN and dorsal horn of the sacral segment of spinal cord in control group. The structure surrounding the other neurons neuraxis dendrite and other apophysis of microglia cells is connected with this apophysis of microglia cells expressing positive substance of P2X4 receptor. In the IBS group, the positive substance of P2X4 receptor expressed significantly in inhibitory synapse, and partial positive substance of P2X4 receptor expressed in synaptic complex and some neurons. And yet, the positive substance of P2X4 receptor expression in apophysis of microglia cells was obvious. Conclusion P2X4 receptor is a factor, which can active microglia, and perhaps is an important module to induce the increased visceral sensitivity.