Muntingia calabura Modulates Alveolar Matrix Metalloproteinase-9 (MMP-9) and Decreases The Alveolar Diameter in Sprague-Dawley Rats Exposed to Cigarette Smoke

Abstract

Exposure to cigarette smoke is a major risk factor for chronic obstructive pulmonary disease (COPD), characterized by oxidative stress and inflammation. The fruit of Muntingia calabura demonstrates significant antioxidant and anti-inflammatory properties. This study investigates the effects of Muntingia calabura fruit extract on matrix metalloproteinase-9 (MMP-9) expression and changes in alveolar diameter in Sprague-Dawley rats subjected to cigarette smoke exposure. Eighteen male Sprague-Dawley rats were randomly assigned to three groups: control (K), treatment 1 (P1) receiving 100 mg/kg body weight/day of M. calabura extract, and treatment 2 (P2) receiving 200 mg/kg body weight/day of the extract. All groups were exposed to cigarette smoke from burning seven cigarettes daily for four weeks. MMP-9 expression was assessed via immunohistochemistry, and alveolar diameter was measured using Optilab software. Both treatment groups exhibited a significant increase in MMP-9 expression compared to the control group (p < 0.0001). Alveolar diameter was significantly reduced in the P2 group compared to P1 and K (p < 0.0001). A negative correlation was observed between MMP-9 expression and alveolar diameter (r =-0.384, p < 0.0001). Administration of Muntingia calabura fruit extract enhances MMP-9 expression and decreases alveolar diameter in rats exposed to cigarette smoke, suggesting its potential protective role against smoke-induced pulmonary damage.