Experimental Study Of Therapeutic Action Of Tea Polyphenol Injection On Acute Lung Injury From Global Cerebral Ischemic-Reperfusion In Rat

Objective: To investigate the effects of tea polyphenol(TP) on acute lung injury from global cerebral ischemic reperfusion.Methods: Healthy male SD rats, of which the weight was 220±20g, were divided into 5 groups at random, and the 5 groups contain sham-operation, model, TP50, TP100, and Nimodipine(Nim)control. The global cerebral ischemia-reperfusion damage model was produced by the improved Pulsinelli-Brierley method. Some indexes were observed, including the activity of superoxide dismutase(SOD),concentration of malondialdehyde (MDA) and expression of lipopolysaccharide receptor(CD14)in the lung.Results: Observed tissues by the microscope, and compared with sham-operation group, both pulmonary and cerebral pathologic changes were obvious in model group, and the changes in TP50, TP100 and Nim groups were milder than model group. Compared with sham-operation group, the concentrations of MDA in the lung of model group rose significantly(22.24±8.13 vs 32.60±5.85; P<0.05).Compared with model group, the concentration of MDA in the lung of TP100 and Nim group reduced significantly (15.31±2.11 vs 18.77±3.98; P<0.01). Compared between TP groups ,there were significantly differences(P<0.01). Meanwhile, dose-effect relationship could be concluded. Compared with sham-operation group, the activity of SOD in the lung of model group reduced significantly(1.26±0.59 vs 0.28±0.26; P<0.01). Compared with model group, the activity of SOD in the lung of TP100(0.87±0.27; P<0.01)and Nim group(0.73±0.21) rose significantly (P<0.01; P<0.05). As to the influence of TP on expression of CD14 in the lung of the model of cerebral ischemic-reperfusion injury,compared with sham-operation group, the expression of CD14 in model group rose significantly[(1.4±0.3 vs 39.0±8.5)%; P<0.01]. Compared with model group[(3.7±3.9)%], the expression of CD14 of the other three model group reduced significantly[TP100(7.0±1.9)%; TP50(25.1±7.5)%; Nim group(12.7±5.1)%; P<0.01]. Compared between TP50 and TP100 [(25.1±7.5)% vs (7.0±1.9)%], there was a significant difference (P<0.01), which existed dose-effect relationship.Conclusion: TP by intravenous injection can significantly reduce the injuries of brain and lungs from the global cerebral ischemic reperfusion. Maybe the mechanism of the protection is according to increasing the tissue's ability of anti- oxidation ,strengthening the activity of oxygen free radical elimination enzymes as well as resisting the attack of endotoxin .