非压迫性髓核导致大鼠背根神经节的病理变化

Non-compressive Effect on Ultra-structural Changes in the Dorsal Root Ganglion Following Autograft of Nucleus Pulposus in Rats.

目的观察大鼠脊神经节自体髓核移植后,大鼠左后肢疼痛行为学和神经节非压迫性损伤的超微结构的变化。方法78只SD大鼠随机分成空白组(6只)、假手术组(36只)和自体髓核移植模型组(36只)。模型组大鼠行腰5左侧半椎板切除,暴露腰5背根神经节,取尾部的自体髓核组织置于背根神经节表面,假手术组背根神经节表面放置等量的自体肌肉,每组用von Frey hair测量手术前后大鼠后肢机械刺激缩爪阈值,于术后7 d、14 d和21 d取材用光镜和电镜行病理学观察。结果空白组和假手术组左后肢机械刺激缩爪阈值手术前后无明显降低,模型组术后有明显机械刺激缩爪阈值降低(P<0.05);模型组脊神经节出现长达21 d的病理损伤改变,表现为不同程度的神经节充血水肿,节细胞线粒体空泡变,溶酶体增多,内质网肿胀扩张,有的甚至出现细胞核皱缩;神经纤维的轴突内细胞器减少,髓鞘肿胀疏松,个别甚至崩解;假手术组仅在7 d时轻度的神经节充血水肿,细胞有轻微的粒体空泡变;空白组和假手术组的14、21 d脊神经节无病理损伤改变。结论非机械压迫的自体髓核可引起大鼠脊神经节超微结构严重损伤和后肢机械痛敏。

Objective To study the non-compressive effect on the pain praxiology and ultrastructural changes in the dorsal root ganglion （DRG） following autograft of nucleus pulposus in rats. Methods Seventy-eight male Sprague-Dawley rats were randomly divided into 3 groups： blank group （n ： 6） , sham-operatod group （n = 36） and model group （n = 36）. The latter two groups underwent a left fifth DRG hemilaminectomy and LS-L6 facetectomy on the left side to expose the left L5 DRG and a part of dura sac. Autologous nucleus pulposus was harvested from the tail and applied to the 1-5 DRG in nucleus pulposus group whereas equimolar autologous muscle was applied to the L5 DRG in sham-operated group. The left hind paw withdrawal Threshold （PWT） were measured by Von Frey filaments method before and after operation. Pathological changes were evaluated by electron and light microscopy on day 7, 14 and 21 after operation. Results There was no significant decrease of PWT after operation In the blank group and sham group wheras there was significant postoperative decrease of PWT in the model group on 21 day after operation. The Pathological changes in model group included different degree hyperemia and edema in Ganglion, mitochondria vesiclization, lysosome increase, endoplasmic reticulum dilation and even karyon crimpling. The changes were also accompanied by reduction of organelle, hypertrophy and loosen of myelinsheath and even disintegration in some axons. On the contrast, only slight Ganglion hyperemia and edema and mitochondria vesiclization occurred in the neurons of sham-operated group on day 7 ; No significant damage was observed on DRG of blank group and sham-operated group on day 14 and 21. Conclusions Autologous nucleus pulposus applied to DRG without me- chanical compression can lead to significant uhrastructural damage and tactile allodynia in rats.