The Experiment Study Of Protective Effects Of Pretreatment With Erythropoietin On Lung Ischemia-reperfusion Injury In Rabbits

Objective: To investigate the protective effect of pretreatment with erythropoietin (EPO) on lung ischemia-reperfusion injury in rabbits, and explore its possible mechanisms. Thus to provide the basis of clinical lung protection.Methods: We established rabbits model of the lung ischemia-reperfusion injury in vitro. 48 rabbits were randomly divided into two groups:as contrast group(group C),ischemia-reperfusion group (group IR)and erythropoietin preconditioning group(group EP),each group has 16 rabbits. In contrast group, after the open-chest, not give ischemia and reperfusion allogeneic blood 2h directly. The group EP, a single dose of EPO were intravenous 5000 U/kg 24 h prior to operation, the group IR, the same dose saline were ingtravenous 24h prior, the harversted lung blocks were flushed with and stored in the modified Low potassium dextrane (LPD) solution at 4℃for 6h. To reperfusion with allogeneic blood 2h after stored 6h.After 1h ischemia (T1), reperfusion(T2), after reperfusion 1h (T3),2h (T4) each group the lung tissue samples were taked respectively for TUNEL, the wet/dry ratio, malondialdehyde(MDA)content and superoxide dismutase(SOD) vitality tested, caspase-3 protein expression, H-E stain and electron microscopy.Results: 1,TUNEL test results:After reperfusion compared with the group C the lung cell AI of the group IR and EP was higher(p< 0.05 or p< 0.01), however, the lung cell AI of the group EP was lower than that of group IR (p<0.05). 2,Compared with the group C, started when the infusion, the lung tissue W/D of group IR and EP was not statistically significant (p> 0.05). After reperfusion the lung tissue W/D of group IR and EP was increased(p<0.05 or p<0.01). Compared with the group IR, after reperfusion the lung tissue W/D of group EP was lower (p< 0.05 or p< 0.01). 3,Compared with the group C, started when the infusion and after reperfusion the MDA content of group IR was increased(p<0.05 or p<0.01), and for the group EP, after reperfusion the MDA content was increasing(p<0.05 or p<0.01). But the MDA content of group EP was lower than group IR (p< 0.05 or p< 0.01). Compared with the group C, began pouring and after reperfusion, the SOD vitality of group IR was decreased (p< 0.05 or p< 0.01), after reperfusion that of group EP was decreased (p< 0.05); But compared with the group IR, the SOD vitality of group EP was increased (p< 0.05). 4,Started when the infusion, caspase-3 expression in lung tissue of the group IR was more increased than that of group C( p<0.05); Compared with the group C, after reperfusion, caspase-3 expression in lung tissue of the group IR and EP was increased(p< 0.05 or p< 0.01), however, after reperfusion 2h that of group EP was lower than group IR(p<0.05). Under the microscope, the group C contents only a small amount of yellowish-brown positive result, group IR and EP found plenty of yellowish-brown positive outcome, but the group EP was less than group IR obviously. 5,With the microscope the alveolar cellular structure of group C was nomal generally. In the group IR diffuse changes occur in lung tissue, it contents alveolar cell swelling, alveolar interstitial edema, congestion and inflammatory reaction significantly, pulmonary capillary expansion, congestion and leukocyte aggregation. Compared with group IR, injury of the lung tissue cells in group EP was significantly reduced, with alveolar leakage decreased, white blood cell aggregation to reduce. Perspective electron microscope: the structure ofⅠ,Ⅱ-type alveolar cells and vascular endothelial cell of the group C was basically normal.ThetypeⅠalveolar cells of group IR become flat, with basement membrane thickening and cytoplasmic vacuoles appearance. TypeⅡalveolar cells were reduction of microvilli, mitochondrial swelling, mitochondrial cristae reduced and osmiophilic lamellar body to reduce. Endothelial cell swelling, basement membrane thickening, cell gap widened, chromatin aggregation, nuclear degeneration and necrosis. TypeⅠandⅡalveolar cell of group EP structure was basically normal, nuclear chromatin margination, mitochondria were round or oval-shaped ridge clear, microvilli, and lamellar body structure, no significant change in a small number of mitochondria may appear swollen. Mild swelling of endothelial cells, basement membrane normal.Conclusions: 1,The injury caused by lung ischemia-reperfusion, mainly show that the destruction of alveolar structure; pulmonary edema, congestive caused by inflammatory response, while lung tissue cells are also involved in LIRI. 2,Erythropoietin preconditioning in rabbit isolated lung ischemia-reperfusion injury significantly protective effect may be related to participation in anti-inflammatory, inhibit the cell apoptosis and anti-oxidation effects of postischemia-reperfusion.