目的观察鞘内注射PI3K激酶抑制剂wortmannin对骨癌痛大鼠痛阈及其脊髓炎症因子表达的影响,探讨PI3K激酶与炎症因子在骨癌痛发病机制中的可能作用。方法雌性SD大鼠44只,随机分为4组(n=11):假手术(S)组、假手术+鞘内注射wortmannin(SW)组、胫骨癌痛(A)组、胫骨癌痛+鞘内注射wortmannin(AW)组。S组、SW组左胫骨上端骨髓腔各注入Hank’s 液10μl,A组、AW组左胫骨上端骨髓腔各注入Walker256癌细胞悬液10μl。骨癌痛造模同时均进行腰34间隙鞘内置管,模型制备成功后第9天,s组、A组鞘内注射0.9%生理盐水10μl,SW组、AW组鞘内注射wortmannin(0.05μg/μl)10μl。给药前后每10min测试1次大鼠左后足机械痛闯值,且在给药30min后取各组大鼠左侧L4-L6脊髓背角,采用酶联免疫吸附法测定脊髓背角炎症因子白细胞介素1β(IL-1β)、白细胞介素6(IL-6)和肿瘤坏死因子α(TNF-α)的表达情况。结果建模后第9天,s组、SW组、A组、AW组给药后30min机械痛闭值分别为(30.1±4.3)、(31.7±1.3)、(17.2±2.0)、(24.8±2.3)g,差异有统计学意义(F=22.403,P〈0.01);与S组、SW组比较,A组机械痛阈值下降;与A组比较,AW组机械痛阈值增高。给药后30min,S组、SW组、A组、AW组大鼠脊髓背角TNF-α含量分别为(84.5±6.3)、(78.7±12.5)、(110.5±7.3)、(57.8±4.6)pg/ml,差异有统计学意义(F=28.119,P〈0.01)。与S组、SW组比较,A组大鼠脊髓TNF-α含量明显升高;与A组比较,AW组大鼠TNF-α含量均明显降低。结论鞘内注射wortmannin可缓解骨癌痛大鼠痛觉过敏,抑制骨癌痛大鼠脊髓背角炎症因子TNF-α的表达上调,PI3K激酶可能通过调节TNF-α的表达参与骨癌痛的发生。
Objective To investigate the roles of PI3K in bone cancer pain, the present study was performed to demonstrate the changes of pain-related behavior and the production of IL-1β, IL-6 and TNF-α after intrathecal injection of wortmannin (antagonist of PI3 K receptors) in rat model. Methods A total of 44 SD rats were randomly divided into 4 groups, sham group (group S), sham + wormannin group (group SW), cancer group (group A), cancer + wortmannin group (group AW). Group S and group W were injected with 10 μl Hank's solution into left tibial medullary cavity; group A and group AW received injections of Walker 256 mammary cancer cells( 10 μl, 2 ×10 cells/ml) into the same place to establish the model of bone cancer pain. In the meantime intratheacal catheterization was performed between L3 and L4 vertrbra on the rats of every group. Nine days after the operation, group S and group A received a single intratheacal injection of saline (0. 9%, 10 μl), group SW and group AW received intratheacal wortmannin0. 5 μg/10 μl. Mechanical withdrawal thresholds were measured on the left hind paw before and every 10 min after intrathecal injection. Then the L4-L6 sections of spinal cord 30 rain after injection were collected to determine the expression of IL-1 β, IL-6 and TNF-α. Results At 30 rain post-injection, mechanical withdrawal thresholds of groups S, SW, A and AW were ( 30. 1 ±4. 3 ), ( 31.7 ± 1.3 ) , ( 17.2±2. 0), (24. 8 ± 2. 3 ) g respectively at Day 9 postinoculation ( F = 22. 403, P 〈 0. 01 ), the mechanical withdrawal thresholds in group AW increased obviously versus group A. The expressions of TNF-α in groups S, SW, A andAWwere (84.5 ±6.3), (78.7 ±12.5), (110.5 ±7.3), (57.8 ±4.6) pg/ml. Compared with groups S and W, the expression of TNF-α in group A showed a significant upregulation (F =28. 119, P 〈 0. 01 ). Conclusions An intratheeal injection of wortmannin may alleviate hyperalgesia, and inhibit the up- regulated expre