Interventional Effects Of Astragalus Injection On Pressure Ulcers With Ischemia-reperfusion Injury In Rats

Objective To investigate the effects of Astragalus Injection(AI) on the pressure ulcers causedby ischemia-reperfusion injury of rats and explore its protective mechanism.Methods Forty Sprague-Dawley rats were randomly divided into five groups, including8ratsin each group: control group, model group, intervention group with high-dosage AI(10ml/kg),intervention group with middle-dosage AI(6ml/kg) and intervention group with low-dosageAI(2ml/kg). The rats in the model and AI groups were treated with physiological saline and AI,respectively, by the way of intraperitoneal injection for a week before ischemia-reperfusioninjury. All rats were subjected to10%Chloral hydrate anesthesia. The control group did notgive any pressure, whereas the other groups were pressurized with34.96kpa. All the rats in thepressurized groups underwent3cycles ischemia-reperfusion and were sacrificed mercifully atthe end of experiment. Color and morphology of the pressurized skin were observed grossly bynaked eyes; each group was adopted with HE staining and the histopathological changes of skinand muscle tissue were observed under optical microscopy; The serum level of nitric oxidesynthase(iNOS), superoxide dismutase(SOD), tumor necrosis factor-α (TNF-α), myelo-peroxidase(MPO), intercellular adhesion molecule-1(ICAM-1) and nitric oxide(NO) weremeasured by enzyme linked assay(ELISA).Results1.The skin of control group had no obvious changes after experiment, while pressurized skin ofthe other groups presented persistent redness and there were no significant differences betweenthe modol and AI groups.2.The color and structure of skin and muscle were normal in control group.Structure was clearand intact and many appendant organs could be found clearly. Muscle fibers packed closely andno obvious inflammatory cells were found. However, In model group, the stratified squamousepithelium cells became thin and the structure became unclear. Muscle fibers had slight rupture, edema and waxy degeneration. muscle tissues showed atrophic and autolytic. A large number ofinflammatory cells were gathered in the pressurized skin and muscle tissues. The damage of AIgroup was significantly decreased than model group.3.Serum ICAM-1levels in intervention group with low-dosage AI had not statisticallysignificant difference compared with control group(p>0.05), The levels of iNOS, TNF-α, MPO,ICAM-1and NO were significantly higher but SOD levels were markedly lower in other groupsthan those of the control group(p<0.01). The levels of NO, iNOS and SOD were not significantdifferent between intervention group with low-dosage AI and model group (p>0.05). However,among iNOS, TNF-ɑ,MPO,ICAM-1,NO and SOD, the difference was statistically significantcompared with model group(p<0.01). Except the difference of SOD was not significantbetween intervention group with low-dosage AI and high-dosage AI (p>0.05), the levels ofiNOS, TNF-ɑ, MPO, ICAM-1, NO and SOD changed obviously among the AI treated groups(p<0.01).Conclusion Astragalus Injection has a protective effect against I/R injury of pressure ulcer ofrats. The mechanism may be related to the inhibition of inflammatory reaction and Oxygen freeradicals after the I/R injury.