Glue solvent inhalation impairs host resistance to Mycobacterium bovis-induced infection in hamsters

Industrial organic solvents present in glue are among the common used psychotropic drugs in Brazil and perhaps worldwide; but few data are available concerning the toxic effects of glue sniffing, with almost no information about immunotoxicity. This seems interesting because several drugs and environmental chemicals are recognized as potential immunotoxicants. The present study investigated the effects of forced inhalation of a toluene/n-hexane 1:1 mixture on hamster resistance to Mycobacterium bovis. Adult hamsters were divided at random into 3 equal groups. Animals of Groups E and E inhaled the mixture of toluene/n-hexane twice daily for 37 d. Group C was placed for the same period of time in identical chambers free of solvents. Two days after the beginning of the experiment, Groups E and C were injected ip with 0.5 ml of an activated suspension of M. bovis; Group E received the same volume of a control solution. Hamsters inhaling the toluene/n-hexane mixture (E) exhibited increased weight loss, increased scores of M. bovis colony forming units isolated from liver, lung and spleen, increased granulomatous areas in the liver, lung and spleen. Inhalation of the toluene/n-hexane mixture for 37 d also increased serum cortisol compared to control hamsters. Tuberculosis is an infection with an intracellular bacterium in which sensitivity is determined mainly by host response. The present data demonstrated impaired defense against M. bovis in hamsters inhaling a toluene/n-hexane mixture for 37 d. Since macrophages are the architectural and functional units of the granulomas in tuberculosis, and no data were found about glue solvent effects on cellular immunity, the present data suggest an indirect effect of glue solvents on macrophage/lymphocyte activity via stress induction and central nervous system stimulation of hormonal (ACTH/cortisol) secretion and/or autonomic nervous system activity.