EFFECT OF POLYETHYLENE MICROPLASTICS ON CARDIO-PULMONARY ENERGY METABOLISM AND HISTOARCHITECTURE IN RATS

Polyethylene microplastics (PE-MPs) represent one of the most pervasive classes of microplastics in the environment. Toxicological studies have demonstrated their capability to induce cellular uptake, membrane disruption, oxidative stress, and metabolic dysfunction. However, their specific impacts on cardiopulmonary energy metabolism and tissue integrity remain poorly characterized. This study investigated the subacute cardiopulmonary toxicity of PE-MPs in male albino rats. Fifteen rats were randomly assigned to three groups: control (normal saline), low-dose (10 mg/kg PE-MPs), and high-dose (100 mg/kg PE-MPs), with five rats per group. Following 14 days of oral administration via gavage, animals were euthanized and cardiac and pulmonary tissues were excised for mitochondria isolation, biochemical analysis and histological assessment. Biochemical analysis revealed a significant (p < 0.05) reduction in cardiac and pulmonary glycolytic enzyme activities of PE-MP-exposed rats, with notable exceptions in pulmonary hexokinase activity in the cardiac lactate dehydrogenase activity. Mitochondrial enzymes activity was markedly suppressed in treated groups compared to controls, excluding cardiac citrate synthase and complex III, and pulmonary succinate dehydrogenase and complex II, which remained unaffected. Mitochondrial oxidative distress and inflammation were also observed in the exposed groups. These findings postulate that subacute exposure to PE-MPs disrupts cardiopulmonary energy metabolism by altering the activity of key glycolytic and mitochondrial enzymes and antioxidant status. This biochemical disruption is accompanied by histological damage, indicating the potential of PE-MPs to induce oxidative stress and inflammation in cardiopulmonary tissues. These results underscore the urgent need for further mechanistic studies and risk assessment of microplastic exposure in mammals, particularly concerning long-term cardiovascular and respiratory health