尿蛋白酶抑制剂防治肺缺血再灌注损伤的实验研究

Ulinastatin,a Human Protease Inhibitor,Attenuates Ischemia-reperfusion Lung Injury

目的 探讨肺缺血再灌注损伤的机制及尿蛋白酶抑制剂对肺缺血再灌注损伤的保护作用。方法 6 0只健康Sprague Dawley大鼠随机分为 3组 :手术对照 (C)组、缺血再灌注 (IR)组、药物治疗 (U )组。每组分别于夹闭缺血的第 4 5min、再灌注后 30、6 0、12 0min 4个时点 ,经颈动脉放血处死大鼠 ,并取血浆和左肺 ,测定血浆肿瘤坏死因子 (TNF α)含量 ,肺组织干 /湿重比值、超氧化物歧化酶 (SOD)含量及在光镜和电镜下观察肺组织病理变化。结果 (1)血浆TNF α含量 :IR组在缺血再灌注后血浆TNF α含量明显增加 ,较C组和U组显著增高(P <0 .0 5 ) ;而U组的TNF α含量在缺血再灌注过程中的变化无显著性意义。 (2 )肺组织SOD含量 :经缺血再灌注后 ,IR和U组肺组织SOD含量较C组同时点均显著下降 (P <0 .0 5 ) ;U组减少的程度明显小于IR组 (P <0 .0 5 )。 (3)肺组织D/W比值 :经缺血和再灌注后 ,IR和U组的肺组织D/W比值都呈进行性下降 (再灌注 6 0、12 0minvs缺血 4 5min ,P <0 .0 1) ;U组下降幅度明显小于IR组 (再灌注 6 0、12 0min时 ,U组vsIR组 ,P <0 .0 5 )。 (4 )肺组织病理变化 :缺血再灌注后IR组肺组织损伤进行性加重 ,毛细血管充血、肺泡间隔炎性细胞浸润、肺泡腔内炎性细胞及炎性液体渗出渐显著 ,电镜下见肺泡?

Purpose: To study the mechanism of lung ischemia-reperfusion injury and the protective effects of ulinastatin on lung ischemia-reperfusion injury. Methods: Sixty healthy Sprague-Dawley rats were randomly divided into three groups: C group, U group and IR group. Five rats were put to death at one of four time points (45 min ischamia 30, 60 and 120 min reperfusion) in each group after blood was collected from the left carotid and them discarded the left lung. The TNF-α concentration in plasma, the dry/wet (D/W) ratio and the contents of superoxide dismutase (SOD) in lung tissue were determined and lung biopsies were also obtained. Results: (1) The TNF-α concentration in plasma: In IR group TNF-α was increased obviously at the 30 min, 60 min, and 120 min reperfusion and it was significantly higher than that in the C group and U group (P < 0.05). The increase of TNF-α was meaningless in the U group. (2) The contents of SOD in lung tissue: SOD in both the IR group and U group were significantly lower in each same time point after ischemia-reperfusion than that in the C group (P < 0.05), but the decreased level of SOD in the U group was obviously less than that in the IR group (P < 0.05). (3) The D/W ratio of lung tissue: After ischemia-reperfusion, the D/W in the IR group and U group were decreasing progressively and reached the lowest at 120 min after reperfusing (60, 120 min reperfusion vs 45 min ischemia, P < 0.01); the degree for D/W decreasing in the U group was obviously less than that in the IR group (at 60, 120 min reperfusion, the U group vs the IR group, P < 0.05). (4) Histological evaluation: In the process of ischemia-reperfusion the lung injury was aggravating progressively in the IR group; there was marked pulmonary capillary congestion, interstital edema and intraalveolar hemorrhage, infiltration; the electron microscopic section of alveolar showed the type II pneumocyte was damaged and lamellar bodies disappeared. The pulmonary pathologic alterations occurred to a lesser degree in the U group compared with the IR group. Conclusions: (1) The lung ischemia-reperfusion injury may have close relationship with cytokinin released increasingly and unbalancingly between free radicals generating and clearing; (2) Ulinastatin, a protease inhibitor, could decrease cytokinin releasing, inhibit neutrophils aggregating and activated in the lungs and increase free radicals scavenging. It could be used to protect lung ischemia-reperfusion injury.