Chung K, Lee B H, Yoon Y W, Chung J M
Marine Biomedical Institute, University of Texas Medical Branch, Galveston 77555-1069, USA.
J Comp Neurol. 1996 Dec 9;376(2):241-52. doi: 10.1002/(SICI)1096-9861(19961209)376:2<241::AID-CNE6>3.0.CO;2-3.
The extent of the sprouting of sympathetic postganglionic fibers in the dorsal root ganglion (DRG) and the peripheral nerves was examined in neuropathic rats at different postoperative times. After the L5 and L6 spinal nerves were ligated on one side, three different pain behavior tests (representing mechanical allodynia, cold allodynia, ongoing pain exacerbated by cold stress) were performed at various time intervals. The sympathetic postganglionic fibers were visualized by immunostaining with antibodies to tyrosine hydroxylase (TH). In the neuropathic rats, all three pain behaviors were fully developed within 3 days after the surgery, maintained up to 2 weeks, and then started to decline gradually afterward. At 20 weeks after neuropathic surgery, pain behaviors were reduced significantly compared to the peak response, but were still higher than the presurgery levels. Sympathectomy, performed 4 days after neuropathic surgery, almost completely abolished the signs of mechanical allodynia and ongoing pain behaviors, and it reduced the behaviors of cold allodynia to approximately half. The numerical density of sympathetic fibers in the DRG of an injured segment was significantly higher at 1, 4, and 20 weeks after neuropathic surgery as compared to the normal, suggesting that there is sprouting of sympathetic fibers in the DRG after peripheral nerve injury. Sprouting of sympathetic fibers in the DRG was extensive as early as 2 days after the spinal nerve ligation, and the sprouted fibers were almost completely eliminated after sympathectomy. The data suggest that sympathetic innervation of the DRG may play an important role in the development and maintenance of sympathetically maintained neuropathic pain.
在不同术后时间点，对神经性大鼠背根神经节（DRG）和周围神经中交感神经节后纤维的发芽程度进行了检查。在一侧结扎L5和L6脊神经后，在不同时间间隔进行了三种不同的疼痛行为测试（代表机械性异常性疼痛、冷异常性疼痛、冷应激加剧的持续性疼痛）。通过用酪氨酸羟化酶（TH）抗体进行免疫染色来观察交感神经节后纤维。在神经性大鼠中，所有三种疼痛行为在手术后3天内完全发展，持续到2周，然后逐渐开始下降。在神经性手术20周后，疼痛行为与峰值反应相比显著降低，但仍高于手术前水平。在神经性手术后4天进行交感神经切除术，几乎完全消除了机械性异常性疼痛和持续性疼痛行为的体征，并将冷异常性疼痛行为降低到大约一半。与正常情况相比，神经性手术后1周、4周和20周时，损伤节段DRG中交感神经纤维的数值密度显著更高，表明周围神经损伤后DRG中有交感神经纤维发芽。早在脊神经结扎后2天，DRG中交感神经纤维的发芽就很广泛，并且在交感神经切除术后发芽纤维几乎完全消失。数据表明，DRG的交感神经支配可能在交感神经维持的神经性疼痛的发生和维持中起重要作用。
