| Objective: To explore the influences of sevoflurane preconditioning combined with postconditioning on expression of nuclear transcription factor κB in lung ischemia-reperfusion injury in rats, so as to provide theoretical basis for the organ-protecting role of combined application of sevoflurane. Methods: 54 healthy male SD rats(clean grade) were provided by animal experimental center of Xinjiang Medical University. The rats weighted 300-350. According to a calculation formula for multiple samples, it was estimated that 54 rats were needed. 54 rats were divided into 3 groups(n = 18) by means of a random number table. Sham operation group(group S): The rats were given intraperitoneal injection for anesthesia and then fixed at supine position. Their right jugular vein was isolated. Deep vein catheterization was performed and then 0.9% sodium chloride was continuously injected. At the same time, rat trachea was isolated. Tracheotomy and tracheal intubation were performed. Animal breathing machine was connected for mechanical ventilation. Ventilation rate was 65-70 times/min, tidal volume was 10 ~ 15 ml/kg and respiratory ratio was 1.0:1.5. Inlet of breathing machine was connected to the end of the breathing loop of anesthesia machine with sevoflurane volatile tank. After 30 min of ventilation, the rats were laid at right lateral position. From the 5th rib of the rat, the left inferior pulmonary ligament was separated by blunt separation and left lung hilum was also isolated. With wet gauze soaked in 0.9% sodium chloride injection to cover the exposed lung tissues, models of group S were established. Lung ischemia-reperfusion group(group I/R): The rat lung tissues were exposed in the same way as group S. And 50 U heparin was injected through common jugular vein for heparinization. 5 min after injection of heparin sodium, non-invasive blood vessels were used to block the separated left lung hilum of rat(including left main bronchus, left pulmonary arteries and veins) at the end of exhalation and then observed. Lung tissue was not expanded during ventilation, and the color was changed from pink to dark purple, suggesting the lung hilum was successfully blocked. 45 min after block, vascular clamps were loosened to recovery blood circulation and ventilation of rat lung tissue, forming reperfusion of lung tissue. Rat lung tissue recovering ventilation and expansion within 5 min and the color returning to color before reperfusion meant successful reperfusion and the reperfusion model was successesful. Sevoflurane preconditioning and postconditioning group(group SP): The rats inhaled 2.1% sevoflurane for 30 min and were washed for 10 min before blocking left hilum of lung. Then the left hilum of lung was blocked for 45 min. The rats stated to inhale 2.1% sevoflurane immediately at reperfusion and for another 30 min to prepare the model of combined treatment group. Six rats were randomly selected for respective 30 min, 60 min and 120 min of reperfusion and then were sacrificed to take lung tissue for the determination of wet/dry weight(W/D) ratio. Tumor necrosis factor-α(TNF-α) content was measured in those lung tissue by ELISA method. PT-PCR was used to detect the expression of NF-κB p65 m RNA in rat lung tissues while Western blot was used to determine the expression of NF-κB. The pathological result of the lung tissue was observed under light microscopy. And injury of rat lung tissue was evaluated. Results: Compared with the group S, W/D ratio, TNF-α content and NF-κB p65 m RNA expression levels and NF-κB activity in the lung tissue were increased in group I/R and group SP at each time point of reperfusion(P<0.05); while compared with the group I/R, W/D ratio, TNF-α content and NF-κB p65 m RNA expression levels and NF-κB activity in the lung tissue were all decreased in group SP at each time point of reperfusion(P<0.05); and pathological results suggested that ischemia-reperfusion injury of lung tissue in group SP were reduced. Conclusion: Sevoflurane preconditioning combined with its postconditioning can reduce the lung ischemia-reperfusion injuries in rats through downregulating the expression of nuclear transcription factor κB in lung tissue. |
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