Objective Polyinosinic-polycytidylic acid (poly IC) plays an important role in the central nervous system damage and repair.This study was to investigate the effect of poly IC on inflammatory response after spinal cord ischemia-reperfusion injury (SCIRI) in rats.Methods A total of 72 healthy adult male SD rats were equally randomized into a sham-operation, an ischemia-reperfusion (IR), and a poly IC group.The abdominal cavities of the rats were cut open and closed again in the sham-operation group and SCIRI models were established in the IR and poly IC groups by clamping the abdominal aorta, followed by reperfusion 60 minutes later and intraperitoneal injection of saline (0.1 mL) and poly IC (1.25 μg/g), respectively.At 6, 24, and 48 hours after modeling, BBB scores were obtained and the contents of TNFα, IL-1β and IFN-β were measured by ELISA.At 48 hours, the expressions of NF-κB and IL-10 were determined by immunohistochemistry, the area of ischemic necrosis in the spinal cord tissue was calculated by TTC staining, and its morphological changes were observed under the optical microscope.Results At 48 hours after modeling, the BBB scores were significantly lower in the IR and poly IC groups than in the sham-operation group (3.80±0.75 and 9.40±0.49 vs 20.00±0.00, P<0.01), though higher in the poly IC than in the IR group (P<0.01).The rats of the IR group showed extensive degenerated neurons in the gray substance of the spinal cord, with scattered foci of bleeding and blood coagulation, while those of the poly IC group exhibited fewer necrotic neurons and basically normal nuclear morphology, though with a few swelling cells.The ischemic necrosis area of the spinal cord tissue was significantly reduced.The expression of NF-κB was decreased while that of IL-10 increased markedly.Compared with the IR group, the poly IC group showed a significant increase in the expression of IFNβ (117.23±6.06 vs 55.65±4.02, P<0.01) and a remarkably decrease in the expressions of TNFα (190.45±4.16 vs 201.82±2.18, P<0.01) and IL-1β (39.27±2.48 vs 50.59±1.47, P<0.01) at 48 hours.Conclusion Poly IC can protect the spinal cord and reduce inflammatory response after spinal cord ischemia-reperfusion injury.%目的 多聚肌苷酸多聚胞苷酸(Poly-IC)在中枢神经系统损伤与修复中起重要作用.文中探讨Toll样受体3(TLR3)配体Poly-IC对大鼠脊髓缺血再灌注损伤(SCIRI)后炎性反应的影响. 方法 72只成年健康雄性SD大鼠随机数字表法分为假手术组、缺血再灌注组、Poly-IC组,每组24只.假手术组只做腹腔打开,缺血再灌注组、Poly-IC组打开腹腔后,夹闭左肾动脉起始水平近心端及左、右髂总动脉分叉水平腹主动脉,60min后再灌注,关闭腹腔,分别腹腔给予0.1mL等渗盐水、1.25μg/g Poly-IC.3组大鼠分别于造模后6、24、48h检测BBB神经功能评分,酶联免疫分析法检测各时间点脊髓组织中肿瘤坏死因子α(TNF-α)、白细胞介素1β(IL-1β)及干扰素β(IFN-β)的含量;各组造模后48h行免疫组化检测核转录因子(NF-κB)及IL-10的表达,TTC染色显示脊髓组织缺血坏死面积,HE染色光镜下观察脊髓组织形态学改变. 结果 各组造模48h时,与假手术组比较,缺血再灌注组、Poly-IC组BBB评分均降低(P<0.01);与缺血再灌注组相比,Poly-IC组BBB评分显著增加[(3.80±0.75)分 vs (9.40±0.49)分,P<0.01],缺血再灌注组脊髓灰质出现广泛的变性神经元,可见散在的出血和凝血灶,Poly-IC组脊髓组织神经元损伤坏死数量减少,细胞核形态基本正常,仍可见少量细胞肿胀.TTC染色结果显示经过Poly-IC治疗后坏死面积明显比缺血再灌注组要小.NF-κB免疫组化检测脊髓组织NF-κB的活性,缺血再灌注组可见大量神经元细胞表达,Poly-IC组阳性表达细胞数量明显减少.检测脊髓组织IL-10的表达,缺血再灌注组可见少量神经元细胞细胞质表达细胞,Poly-IC组阳性表达细胞数量明显增加.与假手术组相比,缺血再灌注组和Poly-IC组TNF-α、IL-1β、IFN-β均明显升高(P<0.05);与缺血再灌注组相比,Poly-IC组TNF-α、IL-1β含量降低(P<0.05),IFN-β含量明显增高(P<0.05). 结论 Poly-IC能减轻后炎性反应,对脊髓有一定的保护作用.
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