Ischemic Preconditioning and Atenolol on Lung Injury After Intestinal Ischemia and Reperfusion in Rats

The aim of this study was evaluate the beta blocker atenolol (AT) and ischemic preconditioning (IPC) strategies for tissue protection against systemic effects of intestinal ischemia (I) and reperfusion (R) injury. Forty-two rats were pretreated with AT (1.5 mg · kg⁻¹), 0.9% saline solution (SS; 0.1 mL), or IPC and then subjected to prolonged occlusion of the superior mesenteric artery for 60 minutes leading to I followed or not by 120 minutes of R, according to the group. For IPC, 5 minutes of I prior to 10 minutes of R were established. After this process of I or I-R, the right lung of each animal was adequately prepared for staining with hematoxylin and eosin and subsequent histologic analysis for quantification of inflammatory infiltrate was done. The left lung was frozen and prepared for assessment of oxidative stress by the quantification of thiobarbituric acid-reactivity substances (TBARS). Histologic analysis showed an important inflammatory infiltrate in the I-R + SS (I-R + SS = 4.5), which was significantly (P < .05) reduced by IPC (I-R + IPC = 3.0) or AT (I-R + AT = 3.0). Likewise, the TBARS levels were decreased by both strategies (I-R + SS = 0.63; I-R + IPC = 0.23; I-R + AT = 0.38; P < .05). Our results showed that AT and IPC attenuate pulmonary lesions caused by intestinal I and R process.