单核趋化蛋白-2中和抗体对骨癌痛大鼠脊髓背角磷酸化细胞外信号调节蛋白激酶表达的影响

目的 观察鞘内注射单核趋化蛋白-2(monocyte chemoattractant protein-2,CCL2)中和抗体后骨癌痛大鼠行为学的变化,并探讨其可能的镇痛机制. 方法 雄性SD大鼠32只,体重180～220 g,采用随机数字表法分为4组(每组8只):假手术+正常IgG组(I组),于大鼠左侧胫骨干骺端骨髓腔内注射10μl Hank's液;假手术+CCL2中和抗体组(Ⅱ组),于大鼠左侧胫骨干骺端骨髓腔内注射10μl Hank's液,在注射Hank's液后第7～9天鞘内注射CCL2中和抗体,每天1次,每次10μl,浓度为103 mg/L;骨癌痛+正常IgG组(Ⅲ组),于左侧胫骨干骺端骨髓腔内注射10 μl(1×107/ml)Walker 256肿瘤细胞;骨癌痛+CCL2中和抗体组(Ⅳ组),在注射肿瘤细胞后第7～9天鞘内注射CCL2中和抗体,每天1次,每次10μl,浓度为103 mg/L.观察造模前及术后1、3、6、7、8、9d大鼠机械缩足反射阈值(mechanical withdraw threshold,PMWT)和热缩足反射潜伏期(thermal withdraw latency,TWL)及脊髓背角磷酸化细胞外信号调节蛋白激酶1/2(phosphorylate extracellular signal-regulated kinases 1/2,p-ERK1/2)的表达. 结果 与Ⅰ组比较,Ⅲ组大鼠的PMWT和TWL在第6～9天明显下降,脊髓背角p-ERK1/2蛋白表达明显增加(P＜0.01);与Ⅲ组比较,Ⅳ组大鼠的PMWT和TWL在第6～9天明显上升(P＜0.01),脊髓背角p-ERK1/2蛋白表达明显下降(P＜0.01);Ⅰ组和Ⅱ组上述指标比较,差异无统计学意义(P＞0.05). 结论 鞘内注射CCL2中和抗体可以部分缓解骨癌痛大鼠的机械性和热痛觉超敏,这种效应可能与抑制p-ERK1/2的表达有关.

Intrathecal injection of monocyte chemoattractant protein-2 neutralizing antibody reduces mechanical allodynia in a rat model of bone cancer pain

Objective To observe the effect of intrathecal administration of monocyte chemoattractant protein-2 (CCL2) neutralizing antibody on pain behavior and explore its possible mechanisms.Methods Thirty-two female SD rats weighting 180-220 g were randomly divided into 4 groups (n=8):sham+IgG group (group Ⅰ),sham+Anti-CCL2 intrathecal group (group Ⅱ),model+ IgG group(group Ⅲ),model+Anti-CCL2 group(group Ⅳ).Rats in group Ⅰ and group Ⅱ were injected with 10 μl Hank's solution into the left proximal tibial medullary cavity,rats in group Ⅲ and group Ⅳ were injected with 10 μl Walker 256 breast cancer cells (1× 107/ml) into the same area.Von-Frey thresholds and thermal radiation reflection threshold were measured before modeling and at 1st,3rd,6th,7th,8th,and 9th day after surgery.The altered expression of phosphorylate extracellular signal-regulated kinases 1/2 (p-ERK1/2) in spinal dorsal horn at different time point was detected by Western blot.Results Compared with rats in group Ⅰ,vonFrey thresholds and thermal radiation reflection threshold significantly decreased in rats of group Ⅲ at the 6th day post-inoculation(P＜ 0.01),compared with rats in group Ⅲ,von-Frey thresholds and thermal radiation reflection threshold significantly increased in rats of group Ⅳ at the 7th day post-inoculation (P＜0.01).In contrast with rats in group Ⅰ,the expression of p-ERK in spinal dorsal horn in group Ⅲ apparently increased(P＜0.01).Compared to group Ⅲ,spinal p-ERK1/2 protein levels of rats in group Ⅳ were lower(P＜0.01).There was no significant difference in the expression of p-ERK1/2 between group Ⅰ and group Ⅱ (P＞0.05).Conclusions Intrathecal injection of CCL2 neutralizing antibody can partially release the mechanical and thermal allodynia induced by bone cancer pain,which may be related to blockade of p-ERK1/2 in the spinal dorsal horn.These results indicated that spinal CCL2 may be involved in the development of rats bone cancer pain via activation of p-ERK1/2 in the spinal dorsal horn.