蛛网膜下腔注射甲氨蝶呤对大鼠胫骨癌痛的影响

目的 评价蛛网膜下腔注射甲氨蝶呤对大鼠胫骨癌痛的影响.方法 雌性未交配SD大鼠48只,体重150～180 g,采用随机数字表法,将其随机分为6组(n=8):假手术+人工脑脊液组(SA组)、假手术+甲氨蝶呤200μg组(SM200组)、骨癌痛+人工脑脊液组(CA组)和骨癌痛+不同剂量甲氨蝶呤组(CM1～3组).CA组和CM1～3组采用胫骨骨髓腔内注射Walker-256乳腺癌细胞制备胫骨癌痛模型,于注射Walker-256乳腺癌细胞后第7天经L5.6蛛网膜下腔分别注射人工脑脊液、甲氨蝶呤50、100和200 μg; SA组和SM200组骨髓腔内注射等体积生理盐水,于相同时点经L5.6蛛网膜下腔分别注射人工脑脊液和甲氨蝶呤200 μg.于注射Walker-256乳腺癌细胞或生理盐水前l d(基础值)、注射Walker-256乳腺癌细胞或生理盐水后第7天(T0)、给药后2、4、8h及1、2、3、5、7 d(Tl～8)时测定大鼠缩足反应阈值(MWT).结果 与基础值比较,CA组和CM1～3组各时点MWT下降(P＜0.05)；与T0时比较,CA组T5～8时MWT下降,CM1组T3-5时MWT升高,CM2组T2～6时MWT升高,CM3组T2～7时MWT升高(P＜0.05)；与SA组比较,CA组和CM1～3组MWT下降(P＜0.05)；与CA组比较,CM1组T4～7时MWT升高,CM2组和CM3组T3-7时MWT升高(P＜0.05).结论 蛛网膜下腔注射甲氨蝶呤可减轻大鼠胫骨癌痛,其效应与甲氨蝶呤剂量有关.

Effects of intraathecal methotrexate on mechanical allodynia in rats with tibial bone cancer pain

Objective To investigate effects of intrathecal methotrexate on mechanical allodynia in rats with tibial bone cancer pain.Methods Forty-eight female SD rats weighing 150-180 g were randomly divided into 6 groups ( n =8 each):group Ⅰ sham operation + artificial cerebrospinal fluid(SA group),group Ⅱ sham operation + methotrexate 200 μg(SM group),group Ⅲ bone cancer pain + artificial cerebrospinal fluid(CA group),group Ⅳ-Ⅵ bone cancer pain + different doses of methotrexate (CM1-3 groups).The model of tibial bone cancer pain was induced by injecting Walker-256 cell into the tibial marrow cavity.CA and CM1-3 groups were intrathecal injected artificial cerebrospinal fluid,methotrexate 50,100 and 200 μg.SA and SM200 groups were intrathecal injected artificial cerebrospinal fluid and methotrexate 200 μg.The mechanical withdrawl threshold (MWT) was measured at day 1 before Walker-256 injection (baseline),7 day after injection (T0 ) and 2,4,8,24 hour and 1,3,5,7 days after intrathecal injection ( T1-8 ).Results Compered with the baseline,MWT was decrease in CA and CM1-s groups.Competed with To,MWT was decreased at T5-8 in CA group,MWT was increased at T3-5 in CM1 group,at T2-6 in CM2 group and at T2-7 in CM3 groups.MWT was decrease in CA and CM1-3 groups as compered with SA group; MWT was increased at T4-7 in CM1 group and at T3-7 in CM2 and CM3 groups.Conclusion Intrathecal injection of methotrexate can reduce tibial bone cancer pain in rats.