Apoptosis and expression of bax and bcl-2 mRNA in bleomycin-induced lung injury in rats

To study the morphology,the incedence of apoptosis and the expression of bax,bcl 2 and bcl 2mRNA in bleomycin induced lung injury in rats,wistar rats were intratracheally instilled with bleomycin(5?mg/kg of body weight).The animals injected with sterile saline were anesthetized and killed at 14 days after bleomycin instillation.HE staining,electron microscopy,terminal deoxynucleotigyl transferase mediated dUTP nick labeling(TUNEL),immunohistochemisty(IHC)and in situ hybridization(ISH)methods were used.The results show that a single instillation of bleomycin leads to the appearance of apoptosis in bronchial and alveolar epithelia cells.The expression of bcl 2 and bcl 2mRNA were downregulated and the expression of bax was upregulated in the alveolar epithelia cells.Those proves that the bcl 2/bax system may play a role in the apoptosis of bronchial and alveolar epithelia cells in this disorder.