大鼠神经病理性痛早期脊髓背角Homer-1a基因的表达

Expression of Homer-1a gene in spinal cord in the early stage of neuropathic pain in rats

目的探讨大鼠神经病理性痛早期脊髓背角Homer-1a基因的表达。方法健康雄性SD大鼠60只，体重200～220g，随机分为3组（n=20）：正常对照组（C组）、假手术组（S组）和慢性背根神经节压迫组（CCD组）。CCD组制备CCD诱导神经病理性痛模型，分别于术前48h（基础状态）、术后4、8、24h时取5只大鼠，测定热痛阈，然后取术侧L4-5，节段脊髓，采用实时定量PCR技术测定脊髓背角Homer-1a基因的表达水平。结果与基础值相比，CCD组术后4、8h时脊髓背角Homer-1a基因表达上调（P〈0．01），术后24h时降至基础值水平（P〉0．05），术后24h时热痛阈降低（P〈0．01）。与C组和S组比较，CCD组术后4、8h时脊髓背角Homer-1a基因表达上调，术后24h时热痛阈降低（P〈0．01）。结论大鼠神经病理性痛早期脊髓背角Homer-1a表达水平迅速而短暂的上调，可能抑制早期痛敏的发生。

Objective To investigate the expression of Homer-1 a gene in the spinal cord in the early stage of neuropathic pain in rats. Methods Sixty healthy male SD rats weighing 200-220 g were randomly divided into 3 groups （n = 20 each）： Ⅰ normal control group （C）; Ⅱ sham operation group （S） and Ⅲ chronic compression of dorsal root ganglion group （CCD） . Neuropathic pain was produced by CCD. A stainless steel wire 4 mm in length and 0.63 mm in diameter was inserted through L5 intervertebral foramen into spinal canal. Paw-withdrawal threshold （PWT） to noxious thermal stimulation was measured at 48 h before operation （baseline） and 4, 8, 24 h after operation （in 5 animals at each time point）. The animals were killed at each time point after pain threshold was measured and the lumbar segment （L4-5 ） of the spinal cord was removed for determination of the expression of Homer-1a gene.Results In CCD group the expression of Homer-1a gene in the spinal cord on the operated side was significantly increased at 4 and 8 h after operation as compared with the baseline before operation and then returned to the baseline level at 24 h after operation while the PWT was significantly decreased at 24 h after operation. Conclusion The expression of Homer-1a gene in the spinal cord is rapidly up-regulated in the early stage of neuropathie pain and can inhibit the early hyperalgesia.