A Study on the Relationship Between the Morphologic Change and Surfactant Protein (SP)-A and Surfactant Protein (SP)-D Levels in Intratracheal Bleomycin-Induced Pulmonary Fibrosis in White Rats / 대한주산의학회잡지

ABSTRACT

OBJECTIVE: Surfactant protein (SP)-A and SP-D are involved in host defense mechanism. The author was prompted to perform a study on morphologic change and SP-A, SP-D level of surfactant after pulmonary injury inflicted by intratracheal bleomycin injection. METHODS: Fifteen white adult rats each weighing 250 g (Sprague-Daw ley) were divided into study (receiving bleomycin, n=9) and control groups (n=6). Study group were given a intratracheal injection of belomycin (5 mg/kg). Two groups were grown for five weeks at twenty five degrees Celsius, after which lung tissue were examined for morphologic change and SP-A and SP-D levels were measured using Western blot assay with densitometer. RESULTS: Before the study, the average weight of the study group was 286.69+/-14.54 g, and control was 286.69+/-14.54 g. Five weeks later, the average weight of the study group was 347.31.31+/-60.53 g and control group 352.71+/-16.84 g. However, no statistical significance was noted. On light microscopy, the control group exhibited normal findings while widening of lung interstitium and fibrotic change coupled with more prominent inflammatory cell infiltration were noted in the study group. The SP-A level were 15.34+/-1.52 ODU/microgram in the study group and 7.70+/-2.81 ODU/microgram in the control. SP-D level were 3.53+/-1.46 ODU/microgram and 7.51+/-2.33 ODU/microgram in the study and control groups respectively, there was a statistical significance (p<0.05). CONCLUSION: The morphologic change after pulmonary fibrosis induced by intratracheal bleomycin injection in white rats can be summarized as chronic inflammatory cell infiltration, fibroblast proliferation, deposition of collagen tissues, and lowering of SP-D level were noted. The increase of SP-A level is subject to further study in the future.