Effects of alcohol and combined antiretroviral drug interactions on pulmonary histomorphology in diabetic male Sprague Dawley rats

Abstract

Combination antiretroviral therapy (cART) has been utilized for decades as main therapy against Human Immunodeficiency Virus (HIV) progression and transmission and recently for prevention. The research and usage of cART highlighted its effectiveness against HIV, albeit documented unintended effects such as diabetes induction. Further, diabetes affects millions of adults globally and is characterized by high blood glucose levels caused by lifestyle factors such as sedentary behaviour and excessive alcohol intake. Moreover, alcohol consumption is a major contributor of global burden of disease and death. Diabetes, cART, and alcohol are reported to independently impact the respiratory system and its functionality. However, their combined impact is lacking in literature, especially in HIV-negative individuals on preventative cART regime. This study aimed to fill this knowledge gap by investigating the histomorphological and biochemical effects of cART and alcohol treatment in HIV-naïve diabetic rat lungs. Forty adult Sprague Dawley (SD) male rats were divided into eight groups of five rats each and treated accordingly for 90 days. The groups included untreated negative control (NC), cART- treated (CA), alcohol-treated (AL), cART and alcohol-treated (CAAL), diabetic (DB), diabetic and cART-treated (CADB), diabetic and alcohol-treated (DBAL), and diabetic, cART and alcohol-treated (CAALDB) groups. Blood samples were analyzed for glucose levels and oxidative stress changes using enzyme-linked immunosorbent assay (ELISA) for glutathione peroxidase-1(GPx1) and thiobarbituric acid (TBA) analysis for malondialdehyde (MDA). Lung histomorphological analysis focused on tracheal, bronchiole, vascular, and parenchymal changes using hematoxylin and eosin (H&E), Gordon & Sweet, modified Pentachrome, and Verhoeff van Gieson stains. Additionally, pulmonary inflammation was investigated through C-reactive protein (CRP) expression using immunohistochemistry (IHC). In this study, cART and alcohol co-administration attenuated oxidative stress, tunica media thickness, reticular fibre hyperplasia in the respiratory bronchiole and parenchyma, and induced minimal CRP inflammation in bronchial vasculature. The cART-diabetes interaction resulted in lung surface area reduction, tracheal and bronchial atrophy, and oxidative stress exacerbation. Further, this morbidity induced parenchymal replacement fibrosis (elevated collagen, reduced elastic and reticular fibres) and CRP inflammation (endothelium, muscularis mucosa, and vascular smooth muscle). Alcohol and diabetes interaction exacerbated weight loss, tracheal and bronchial atrophy, and CRP inflammation (bronchial vein and parenchyma). In diabetes, alcohol and cART exacerbated oxidative stress (reduced GPx1 and elevated MDA v levels), while CRP inflammation was observed in the bronchial epithelium and smooth muscle, vasculature, alveoli and alveolar macrophages. Histomorphologically, the triple-morbidity induced tracheal, bronchial artery, and vein atrophy. Such combined impact suggests detrimental capacity against the respiratory system and, consequently, may compromise the functionality. As such, this study calls for persistent pulmonary health monitoring in diabetic individuals on cART regime who regularly consume alcohol.