ABSTRACT
Smokes of mosquito coils are used daily to control mosquitoes during summer season in subtropical and tropical countries. So, the aim of this study was to evaluate the effect mosquito coils smokes on the fine structures of the interalveolar septum of the lung of rat. A prominent effect has been observed in the interalveolar septum of lungs of 25 male rats that were exposed to mosquito-coil smokes with d-allethrin at airborne particles concentration of 1.27 mg/m3, 7 hrs. /day, 7 days/week for 3 months. In addition to another group of air exposure animals as a control group. Marked hypertrophy and proliferation of disorganized type II alveolar cells with apical microvilli were found to contain numerous vacuolated lamellar bodies. The presence of numerous extravasated red blood cells in the interstitial and alveolar spaces indicates that transient separations of cell junctions of endothelial cells of capillaries to get out blood corpuscles and platelets leading to haemorrage and consequently clotting. Increased frequency of alveolar macrophages, in addition to, the presence of neutrophil and plasma cells are characteristics of these inflammatory processes. The interalveolar septum had been increased in thickness due to proliferation of myofibroblasts and a prominent increase in collagen synthesis