INHALATION OF MYCOBACTERIUM TUBERCULOSIS PROTEIN DERIVATIVE IN A TRIAL FOR TREAT MENT OF INDUCED ASTHMA IN GUINEA PIGS. A NOVEL STUDY

Study objective : Current bronchial asthma therapies have limited long - term effects. Vaccine strategies altering the underlying immune response have been focused upon. Several studies have argued that BCG vaccine may be applied to treatment of allergy by i nducing an immune deviation from Th2 to Th1. Based on the same hypothesis; a novel tuberculin inhalation therapy was tried in this study. Materials and Methods: 30 healthy guinea pigs were randomized into: control group (subjected only to saline inhalation ), asthmatic group (Ovalbumin - sensitized and challenged) and tuberculin pretreated group. Respiratory function was monitored and histopathologic examination of the lung tissue was performed using haematoxylin and eosin stain and scanning electron microscop y. Results : There was a highly significant difference (p <0.001) when comparing the post inhalation airway resistance values (sRAW) and tidal volume (VT), the mean change and mean percentage change in sRAW, and the mean change and mean percentage change in VT, of the sensitized - untreated group with both the control and the sensitized tuberculin pretreated group. Histopathologically: In asthmatic animals there were constriction of small bronchioles and mononuclear cellular infiltration, emphysematous widenin g of some alveolar sacs. The mean thickness of interalveolar septa was significantly increased; also the mean number of mast cells, eosinophils and macrophages were significantly increased. Using scanning electron microscope numerous goblet cells, accumula ted mucous and hypertrophied type II pneumocytes were clearly seen. Pretreatment with tuberculin inhalation minimized most of the previous changes. Conclusion : tuberculin inhalation can be a promising therapy for asthma that preserves the lung histopatholo gical and functional changes