Environmental tobacco smoke in rats

We conducted this study to identify the effect of subchronic cigarette smoke inhalation on the vocal cord mucosa of the rat.

Experimental study.

Department of Otolaryngology, School of Medicine, Karadeniz Technical University, Trabzon, Turkey

Twenty-four male Wistar rats were divided randomly into experimental and control groups. The experimental group of rats was exposed to cigarette smoke for 2 hours each day over 60 consecutive days, and the control group was treated in an identical fashion but was exposed only to room air.

Transmission electron microscopic examination of the rat vocal cords.

We found very high levels of plasma thiocyanate after exposure to smoke in the experimental group but no increase in the control group. In the experimental group, mean plasma thiocyanate concentrations of 3.7 +/- 0.5 and 119 +/- 11.4 mmol/L were measured before and after exposure to tobacco smoke, respectively (p < .05). On the contrary, mean plasma thiocyanate levels of control rats were found to be 3.0 +/- 0.4 and 3.9 +/- 0.4 mmol/L, respectively, before and after exposure. In the experimental group, the epithelium covering the true vocal cords shows disturbed stratification. Some cells exhibit loss of desmosomal connections between cells and enlargement of the intercellular space.

Our study demonstrates that the larynx in laboratory animals is one of the sensitive and useful targets for assessing the harmful effects associated with environmental tobacco smoke.