丙戊茶碱对糖尿病痛性周围神经病变大鼠脊髓星形胶质细胞活化的影响

Effect of propentofylline on activation of astrocytes in spinal cord in a rat model of diabetic neuropathic pain

目的评价丙戊茶碱对糖尿病痛性周围神经病变大鼠脊髓星形胶质细胞活化的影响。方法清洁级SD大鼠40只，月龄2月，雌雄不拘，体重180—200g，腹腔注射1％链脲佐菌素60mg／kg以制备大鼠糖尿病痛性周围神经病变模型。取模型制备成功的大鼠20只，随机分为糖尿病组（DM组）和丙戊茶碱组（PP组），每组10只；另取10只同月龄SD大鼠作为对照组（NC组）。PP组和DM组在注射链脲佐菌素后第28天开始，每天分别腹腔注射丙戊茶碱10mg／kg和等容量生理盐水，注射1周。于注射链脲佐菌素前（T1）、注射链脲佐菌素后2、7、t4、21、28、35d（T2～7）时取尾静脉血样0．1ml测定血糖水平；于T1、T3～7，时测定大鼠右后爪机械缩足反应阈值（PWT）；T7时处死大鼠，取L4.5脊髓制备切片，采用免疫组化法检测神经胶质纤维酸性蛋白（GFAP）表达。结果与T1时比较，DM组和PP组T2-7时血糖水平升高，T4～7时PWT降低（P〈0．01）；与NC组比较，DM组和PP组T2-7时血糖水平升高，T6-7时PWT降低，T7时GFAP表达上调（P〈0．01）；与DM组比较，T7时PWT升高，GFAP表达下调（P〈0．05）。结论丙戊茶碱可能通过抑制脊髓星形胶质细胞活化减轻大鼠糖尿病神经病理性痛。

Objective To investigate the effect of propentofylline on activation of astrocytes in the spinal cord in a rat model of diabetic neuropathic pain （ DNP）. Methods Pathogen-free SD rats of both sexes aged 2 months weighing 180-200 g were used in this study. Diabetes was induced by intraperitoneal （IP） 1% streptozocin （STZ） 60 mg/kg. Blood glucose level was measured before （T1） and at 2, 7, 14, 21, 28, 35 days after IP STZ injection （T2-7 ）. Diabetes was confirmed by blood glucose level 〉 16.7 mmol/L. Paw withdrawal threshold to yon Frey filament stimulation （PWT） was measured at T1 , T3-7 . Induction of neuropathic pain was considered successful in animals with PWT reduced by more than 50 % of the baseline. Twenty animals in which DNP was successfully induced were randomly divided into 2 groups （ n = 10 each） ： group Ⅰ diabetes mellitus （DM） and group Ⅱ propentofylline （PP）. Another 10 age-matched normal rats served as control group （NC）. Group PP received IP propentofylline 10 mg/kg once a day for 7 consecutive days .starting from T6 . The animals were killed at T7 and the lumbar segment of the spinal cord was removed for determination of glial fibrillary acidic protein （GFAP） in the astrocytes in the spinal cord by immuno-histochemical assay. Results PWT was significantly lower at T4-7 in group DM and PP than in control group （NC） and was significantly higher at T7 in group PP than in group DM. Immuno-histochemical assay showed that GFAP-positive astrocytes in the dorsal horn of the spinal cord was significantly increased in diabetic rats and propentofylline significantly attenuated the increase. Conclusion Inhibition of astrocytes in the spinal cord is involved in attenuation of diabetic neuropathic pain by propentofylline.