Induction of alopecia in mice exposed to cigarette smoke

Besides being responsible for a high proportion of those chronic degenerative diseases that are the leading causes of death in the population, tobacco smoking has been associated with skin diseases. Smoke genotoxicants are metabolized in hair follicle cells, where they form DNA adducts and cause DNA damage. The suspicion was raised that, in humans, a link may exist between smoking and both premature grey hair and hair loss. In order to check this hypothesis, we carried out a study in C57BL/6 mice exposed whole-body to a mixture of sidestream and mainstream cigarette smoke. After 3 months exposure, most mice developed areas of alopecia and grey hair, while no such lesions occurred either in sham-exposed mice or in smoke-exposed mice receiving the chemopreventive agent N-acetylcysteine with drinking water. Cell apoptosis occurred massively in the hair bulbs at the edge of alopecia areas. Smoke-exposed mice had extensive atrophy of the epidermis, reduced thickness of the subcutaneous tissue, and scarcity of hair follicles. On the whole, exposure to smoke genotoxic components appears to alter the hair cycle with a dystrophic anagen pattern. Although this mechanism is different from that of genotoxic cytostatic drugs, N-acetylcysteine appears to exert protective effects in both conditions.