Comparative 13-week cigarette smoke inhalation study in Sprague-Dawley rats: evaluation of cigarettes with two banded...

This study compared the toxicological responses of Sprague-Dawley rats exposed nose-only to mainstream smoke (MS) from Test cigarettes (1, 2, and 3) to those of Control cigarettes without banded cigarette paper technologies (BCPT). Test cigarettes 1 and 2 had bands based on one technology (different band weight application) while Test cigarette 3 had bands based on another technology. The banded papers are representative of current marketed technologies. Rats were exposed to humidified HEPA filtered air (Sham) or to MS at concentrations of 0.06, 0.20, or 0.80 mg wet total particulate matter per liter air. Each exposure group contained 30 animals/sex (sentinel had 20 animals/sex). The study had two phases (13 weeks each): MS exposure (1 h/day, 5 days/week) and recovery without smoke exposure. Endpoints included clinical observations, respiratory physiology, hematology, serum chemistry, blood carboxyhemoglobin (COHb), serum nicotine, body/organ weights, gross pathology, and histopathology. Comparisons conducted were: Sham exposed vs. all cigarettes, Control cigarette vs. all Test cigarettes, and Test 1 vs. Test 2. Control and Test MS had comparable effects on respiratory physiology, COHb, serum nicotine, serum chemistry, and hematology. While some minor differences were observed, Control and Test MS had comparable effects on clinical signs, body/organ weights, and gross pathology/histopathology. Consequently, exposure of rats to equivalent MS concentrations from the four cigarettes induced similar toxicological responses in this study.