Effect of second-hand smoke on the immunological parameters of wistar rats and their offspring

The literature covers multiple negative effects of active and passive tobacco smoking upon the human body and experimental animals. Much lesser attention is given to the features of the immune system in offspring from the passively smoking experimental animals. In previous works, we studied physiological and immunological parameters in the infant rats born from passively smoking rats. The present work expands the scope of this direction and is devoted to assessment of immunological parameters in passively smoking pregnant rats and their offspring. Quantitative determination of immunological parameters was carried out in pregnant Wistar rats exposed to passive tobacco smoking and in 65 pup rats from smoke-exposed and nonexposed animals. The experimental rats were exposed to tobacco smoke for 8 hours from the 1st to the 20th day of pregnancy. In all animals, the body weight, thymus and spleen, the number of white blood cells, thymocytes, splenocytes, and myelocaryocytes were determined. On the 20th day of pregnancy, the smoking rats showed a significant decrease in the weight of animals, the number of thymocytes and myelocaryocytes. A decreased body mass of animals and their thymus glands, lower number of thymocytes were registered in pup rats born from smoking females as compared with control animals. These changes in immunological parameters may be based on a number of possible reasons. On the one hand, tobacco smoke promotes activation of free-radical processes with a simultaneously decreased efficiency of antioxidant mechanisms. This activation may result from exposure to the components of tobacco smoke, in particular, chromium, as a metal of variable valence, as well as benzene, which is transformed by the free-radical oxidation mechanisms. On the other hand, some tobacco smoke components may promote apoptosis which plays a significant role in the cellular exhaustion of immunogenesis system. Moreover, a decreased number of thymocytes may be caused by their migration from cortical areas to the medulla, followed by release into bloodstream. Thus, the results obtained indicate that the detected changes in these parameters are more pronounced in pregnant rats who were exposed to tobacco smoke and their offspring, and expand the knowledge of changes in the immune system in the offspring of passively smoking animals. The presented data may present a basis for development of drugs that reduce toxic effect of ecotoxicants, including passive tobacco smoking.