Comparative Histological Study of Possible Ameliorative Role of Angiotensin Converting Enzyme Inhibitors Versus Angiotensin Receptor Blockers on Lipopolysaccharides-Induced Acute Lung Injury in Adult Male Albino Rats

Background and aim of the work: One severe form of respiratory failure is acute lung injury (ALI). Early detection and supportive care are critical to improve outcomes. Investigating the effectiveness of angiotensin converting enzyme inhibitors against angiotensin receptor blockers in alleviating ALI induced by lipopolysaccharides (LPS) in adult male albino rats is the aim of this investigation. Materials & Methods: This study involved 26 male albino adult rats, about 12 weeks old and weighing between 200 and 220 grams that were divided into the following categories: Group I (N=6) is the control group. Group II (LPS only) (N=5): Rats obtained injections of LPS (5 mg/kg) IP once, then sacrificed after 6 hours. Group III (Recovery group) (N=5): Rats received LPS once, then sacrificed after 7 days. Group IV (LPS + Captopril) (N=5): Rats received one dose of LPS followed by 50 mg/kg of captopril daily dissolved in one ml of saline orally for seven days before being sacrificed. Group V (LPS + Losartan) (N=5): Rats received one dose of LPS IP followed by 10 mg/kg of losartan daily dissolved in one ml of saline orally for seven days before being sacrificed. Bronchoalveolar lavage fluid (BALF) was analyzed, and lung specimens were evaluated for oxidative stress markers, and histologically examined using Haematoxylin and Eosin (H&E) and immunohistochemical stains. Results: Regarding Groups II and III, LPS disturbed the normal histological configuration of the lung tissues, elevated lung oxidative markers and (BALF) inflammatory cytokines, increased caspase-3,Tumor necrosis factor alpha (TNF-α) and CD68 immunoexpression with decreased CD206 immunoexpression. Group IV exhibited enhancement of the biochemical parameters and the lung tissues' architecture. However, group V showed the best results. Conclusion: Captopril and losartan both can ameliorate the LPS-induced acute lung injury, however, losartan showed superior results.