糖尿病周围神经病变触诱发痛的比较性研究*

COMPARATIVE RESEARCH ON THE TACTILE ALLODYNIA IN DIABETIC PERIPHERAL NEUROPATHY*LIAO Chen-Long1, Zhou Han1, Chen Hong-Jin1, Zhong Wen-Xiang2, Zhang Wen-Chuan1△

摘要:

目的：探索糖尿病周围神经病变触诱发痛的发生机制。方法：在SD大鼠中分别通过链脲佐菌素(Streptozotocin, STZ)腹腔注射及在此基础上行坐骨神经乳胶管置入建立糖尿病模型。于第4周末分别分为触诱发痛阴性与阳性组。比较各组大鼠坐骨神经形态学、髓鞘碱性蛋白（MBP）表达、背根神经节（DRG）及脊髓背角（SDH）神经元的活化情况。结果：STZ注射结合乳胶管置入组的大鼠发生触诱发痛的比例较仅行STZ注射组大鼠显著升高（P<0.05）。触诱发痛阳性组较阴性组发生较显著的脱髓鞘病变，在DRG中具有较多的NF-200阳性神经元激活（P<0.05），在SDH浅表及较深板层中具有较多的神经元激活（P<0.05）。 结论：糖尿病大鼠触诱发痛的发生与有髓神经纤维的损害及其相应DRG神经元与SDH神经元的激活密切相关。

Abstract:

Objects: To identify the difference between diabetic peripheral neuropathy (DPN) with and without mechanical allodynia (MA) in rat model. Methods: Two rat models of DPN were established, one was made by intraperitoneal streptozotocin (STZ) injection, the other was made by STZ injection and sciatic nerve encirclement. Two corresponding control groups were respectively made. Pain behavioral tests were performed every week. By the 4th week, each experimental group was further grouped by MA. Morphometric analysis of sciatic nerves and quantification of myelin basic protein (MBP) were conducted. The numbers of c-fos-immunoreactive neurons in both dorsal root ganglion (DRG) and spinal dorsal horn (SDH) were determined. Results: Totally four experimental subgroups (two with MA and two without) and two corresponding control groups were established by the 4th week. More DPN rats made by STZ injection and nerve encirclement developed MA than those made by solely STZ injection （51/60，10/20，X2=10.147 ，P=0.001<0.05）. In the experimental subgroups, rats with MA had severer demyelination (indicated by morphometric studies and increased MBP) those without. More NF-200 positive neurons in DRG were c-fos-immunoreactive in the experimental subgroups with MA than those without MA (P<0.05). The numbers of c-fos-immunoreactive neurons in both superficial (I-II) and deeper (III-V) laminae of SDH in the subgroups with MA were larger than those in the subgroups without MA (P<0.05). Conclusions: Impairment of primary myelinated fibers and the pattern of neuronal activation in both DRG and SDH are the certain features that differentiated DPN rats with MA from those without.