大鼠乳腺癌骨转移模型中PI3K/Akt信号通路参与诱导疼痛

目的 探讨骨癌痛大鼠模型中PI3K/Akt信号通路参与痛觉过敏的产生和维持及其脊髓机制.方法 Wistar大鼠,体重在180~200 g,将大鼠随机分为3组:癌痛模型组(A组)、假手术组(B组)、正常组(C组),A组大鼠左侧胫骨髓腔内单次注入Walker256乳腺癌细胞建立大鼠胫骨癌痛模型,B组大鼠左侧胫骨注入等量生理盐水,C组做不给药处理.A组造模后第7天,评估筛选成模的大鼠,随机分为3组:癌痛组(A1组)、癌痛+NS组(A2组)、癌痛+抑制剂组(A3组).正常对照组(C组)随机分为2组:空白对照组(C1组)、空白+抑制剂组(C2).A3组和C2组分别在第13、14、21天鞘内注射Akt抑制剂GSK690693,A2组在第13、14、21天鞘内注射等量生理盐水,A1组、B组、C1组均不给药处理.在第0、7、14、21天,分别检测大鼠机械性缩足阈值(mechanical withdrawal threshold,MWT)和热缩腿潜伏期(thermal withdrawal latency,MWT).第21天行为学测试后处死大鼠,取大鼠脊髓L4~L6区段,用免疫组化及Western blot检测大鼠脊髓的磷酸化Akt(p-Akt)水平.结果 实验观察到大鼠的MWT和TWL均显著降低,第7天及14天A1组、A2组、A3组及B组分别与C1组比较,P<0.05,第21天A3组与A1组、A2组分别比较,P<0.05.与C1组比较,骨癌痛模型组大鼠脊髓背角p-Akt表达增强,鞘内注射Akt抑制剂可降低脊髓背角p-Akt的表达.结论 PI3K/Akt信号通路参与了骨癌痛的中枢敏化,在大鼠骨癌痛发生发展过程中起着重要作用.

PI3K/Akt Signal Pathway in Cancer Pain Induced by Bone Metastases

Objective To discuss the role of PI3K/Akt signal pathway in bone metastases pain caused by breast cancer in rats.Methods Wistar rats weighting 180~200 g were selected,all rats were randomly divided into 3 groups:group A was rat model of bone cancer pain ,group B was sham operation group ,group C was the control group .To establish bone cancer pain mod-el,Walker 256 tumor cells was intra-left tibial inoculated in Wistar rats in group A .Group B was given normal saline of the same quantity ,group C received no treatment .7 days after establishment of bone cancer pain model ,the model were evaluated .The rats in group A that were successfully established bone cancer pain model were divided into 3 group:group A1 was rat model of bone cancer pain,group A2 was rat model of bone cancer pain +NS,group A3 was rat model of bone cancer pain +PI3K inhibitor.Rats in group C were divided into 2 groups:group C1 received no treatment ,group C2 received PI3K inhibitor.On the 13th day,14th day,and 21st day,group A3 and C2 were injected by Akt inhibitor GSK690693.By intrathecal injection,group A2 was treated with NS in the same condition ,there was no treatment on group A 1,B,and C1.We measured mechanical withdrawal threshold and thermal withdrawal latency at 0,7,14,21 day.After 21 days when we finished behavior testing at 21 day,the lumbar segment 4~6 of spinal cord were isolated from these experimental rats .The level of p-Akt was detected by immunohistochemistry and western blots.Results It was observed that MWT and TWL were reduced in each experimental group which indicated that the bone pain model was established successfully .The p-Akt level of spinal cord in bone cancer pain model was significantly higher than group C1 on the 21st day.Intrathecal injection of Akt inhibitors may suppress the expression of p-Akt in spinal cord .Conclusion The PI3K/Akt signal pathway plays an important role in the initiation and development of bone cancer pain .