大黄素对大鼠急性脊髓损伤后继发脊髓水肿的影响

Effect of Emodin on Spinal Cord Edema Induced by Acute Spinal Cord Injury in Rats

目的探讨大黄素对大鼠急性脊髓损伤后脊髓水肿的影响及其机制。方法将180只健康雌性Sprague-Dawley大鼠随机分为假手术组(A组),模型组(B组),大黄素低剂量组(C组)、中剂量组(D组)和高剂量组(E组),每组36只。采用Allen法制作大鼠脊髓损伤模型,术后3 d、7 d、14 d及28 d,BBB评分及斜板实验观察大鼠运动功能恢复。术后3 d,HE染色观察脊髓组织病理变化,干湿重法检测脊髓组织含水量,伊文思蓝(EB)染色检测血脊髓屏障(BSCB)通透性,RT-PCR和Western blotting检测水通道蛋白-4(AQP-4)、基质金属蛋白酶-2(MMP-2)m RNA和蛋白表达。结果 BBB评分及斜板实验结果显示,术后7 d、14 d、28 d,C组、D组和E组均优于B组(P<0.05),E组最佳(P<0.05)。术后3 d,HE染色显示,B组损伤节段内有大片出血灶,神经细胞肿胀、破坏,大量炎性细胞浸润,组织间隙增宽,水肿严重,C组、D组和E组上述病理改变改善,其中E组最明显;B组脊髓组织含水量较A组增高(P<0.05),D组、E组脊髓组织含水量低于B组和C组(P<0.05),E组低于D组(P<0.05);B组EB含量高于A组(P<0.05),C组、D组和E组EB含量均低于B组(P<0.05);C组、D组和E组AQP-4、MMP-2 m RNA和蛋白表达均低于B组(P<0.05),E组最低(P<0.05)。结论大黄素能减轻大鼠急性脊髓损伤后的脊髓水肿,促进肢体功能康复,这可能与大黄素下调损伤后脊髓组织AQP-4和MMP-2表达,降低BSCB通透性有关。

Objective To investigate the effect of emodin on spinal cord edema induced by acute spinal cord injury(SCI)and its mechanism.Methods A total of 180 healthy female Sprague-Dawley rats were randomly divided into sham group(group A),model group(group B),and low-dose group(group C),middle-dose group(group D)and high-dose group(group E)of emodin,with 36 cases in each group.The SCI model was established with the modified Allen's method.Functional recovery was evaluated with Basso-Beattie-Bresnahan(BBB)score and inclined plate test three days,seven days,14 days and 28 days after modeling.Three days after modeling,the pathological changes of the spinal cord were observed by HE staining;the water content of spinal cord was detected by dry-wet weight method,the blood-spinal cord barrier(BSCB)permeability was detected by Evans blue(EB)staining,and the expression of aquaporin-4(AQP-4)and matrix metalloproteinase-2(MMP-2)mRNA and protein were detected by RT-PCR andWestern blotting respectively.Results The BBB score and inclined plate scores were better in groups C,D and E than in group B(P<0.05)seven days,14 days and 28 days after modeling,especially in group E(P<0.05).Three days after modeling,HE staining showed that there was a large hemorrhage in the section of group B,the nerve cells were swollen and damaged,and a large number of inflammatory cells were infiltrated,the tissue gap was widened and the edema was severe.The above pathological changes were better in groups C,D and E than in group B,especially in group E.The spinal cord water content was higher in group B than in group A(P<0.05),and was lower in groups D and E than in groups B and C(P<0.05).EB content was higher in group B than in group A(P<0.05),and was lower in groups C,D and E than in group B(P<0.05).The expression of AQP-4,MMP-2 mRNA and protein were lower in groups C,D and E than in group B(P<0.05),especially in group E(P<0.05).Conclusion Emodin can alleviate spinal cord edema,and improve hind limb movement function after SCI,which could be related with the down-regulation of AQP-4 and MMP-2 expression,and the reduction of the permeability of BSCB.