大鼠延髓内脏带星形胶质细胞与神经元对选择性神经病理性痛的反应

Response of astrocytes and neurons in rat medullary visceral zone to the spared nerve injury

目的研究大鼠延髓内脏带（MVZ）内星形胶质细胞与神经元对选择性性神经病理性痛的反应。方法25只成年SD大鼠,其中15只为接受左侧坐骨神经分支选择性损伤（SNI）组,5只作为假手术组,5只为对照组。在术前、术后10d、20d、30d（每时段5只）观察大鼠疼痛行为学并检测机械刺激缩足反射阈值（PWMT）的变化;应用抗Fos蛋白与抗胶质原纤维酸性蛋白（GFAP）或抗Fos蛋白与抗酪氨酸羟化酶（TH）的单一或双重免疫荧光法染色,Confocal显微镜下观察延髓MVZ内GFAP标记的星形胶质细胞的荧光强度,Fos/GFAP双标记星形胶质细胞以及Fos/TH双标记神经元的平均数。结果SNI组大鼠与对照组或假手术组相比,术后10d其痛敏增高（PWMT值降低）,20d痛敏达到高峰（PWMT值最低）。免疫荧光染色显示：SNI术后MVZ内星形胶质细胞表现为激活型,GFAP免疫荧光强度明显增加;孤束核及腹外侧区的Fos/GFAP双标记星形胶质细胞及Fos/TH双标记神经元的平均值显著增高,SNI术后20d达到高峰。结论SNI术后MVZ内的星形胶质细胞和神经元均被激活。

Objective To investigate the response of astroeytes and neurons in the medullary visceral zone （MVZ） to neuropathic pain induced by the spared nerve injury （SNI, the tibial nerve and the common peroneal nerve were sectioned, while the sural nerve was intacted）. Methods The SNI operation and sham operation （only incised the skin of thigh, but the tibial nerve and the common peroneal nerve did not cut） were performed in adult male Sprague-Dawley rats. The paw withdrawal mechanical threshold （PWMT） was measured at 10,20,30 days after operation. By using single or double immunofluorescent staining method, we investigated and measured that the mean fluorescent intensity （ MFI ） of anti-glial fibrillary acidic protein （GFAP, a marker of astroeytes） signal in the astrocytes, the mean member of Fos/ GFAP double labeled astrocytes and Fos / tyrosine hydorxylase （TH） double labeled neurons in MVZ after operation. Results As compared with control or sham groups, SNI induced that the PWMT became significant sensitivity and peaked at 20 days after SNI. The activated astrocytes revealed an activated morphology, the MFI of anti-GFAP signal markedly strengthened, the mean number of Fos/GFAP double labeled astrocytes and Fos/TH double labeled neurons in the nucleus of the tract solitarius （NTS） and the ventral lateral medulla （VLM） increased significantly and peaked at 20 days after SNI. Conclusion The neurons and astrocytes in MVZ were sensitively activated by SNI.