목적: Surfactant Protein (SP)-A와 SP-D는 숙주 방어 기전과 표면 장력 감소에 관여한다. 이에 저자는 블레오마이신으로 유도된 폐 손상 후 예상되는 폐 표면 활성제 기능 부전과 SP-A와 SP-D수치를 알아보고자 본 연구를 시행하였다. 방법: 250 g인 성인 수컷 Sprague-Daw ley 흰쥐 15마리를 실험군(Bleomycin 투여군, n=9)과 대조군(n=6)으로 나누어서, 실험군에게는 기관내로 블레오마이신을 투여하였다. 표준화된 우리에서 25℃의 온도에서 5주간 키운 후 폐 조직을 관찰하고, SP-A와 SP-D 수치는 Western blot assay결과를 densitometry로 측정하였다. 결과: 평균 체중은 실험군이 286.69±14.54 g이었고 대조군은 286.44±09.50 g이었으며, 5주 후평균 체중은 실험군이 347.31±60.53 g이었고 대조군은 352.71±16.84 g 이었으나 통계학적으로 유의한 차이는 없었다. 광학현미경 소견에서 대조군은 정상 소견을 보였으며 실험군에서는 폐 간질이 넓어지면서 섬유성 변화를 보이며 염증세포의 침윤이 대조군보다 현저하였다. SP-A 수치는 실험군 15.34±1.52 ODU/?g, 대조군 7.70±2.81 ODU/?g이었으며 SP-D 수치는 실험군 3.53±1.46ODU/?g, 대조군 7.51±2.33 ODU/?g로 통계학적으로 유의한 차이가 있었다( p<0.05). 결론: 흰쥐의 기관 내 Bleomycin 투여로 유발된 폐 간질 섬유증의 형태학적 변화는 폐간질의 만성염증 세포의 침윤, 섬유아세포의 증식, 교원질의 침착으로 나타났으며 SP-D 수치는 저하되었다. SP-A 수치의 증가는 더 많은 실험을 통한 연구가 필요할 것으로 사료된다.

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/μg in the study group and 7.70±2.81 ODU/μg in the control. SP-D level were 3.53±1.46 ODU/μg and 7.51±2.33 ODU/μg 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.