방사선조사된 폐에서 Melatonin에 의한 TGF-β1 발현의 변화 = The Change of Transforming Growth Factor β1 (TGF-β1) Expression by Melatonin in Irradiated Lung

국문 초록 (Abstract)

목 적: 강력한 항산화 효과를 지닌 melatonin을 전처치하였을 때 방사선유도성 섬유증 과정에서 중요한 사이토카인인 TGF-β1의 변화된 발현양상을 마우스 폐에서 연구하였다. 대상 및 방법: C57BL/6 마우스를 실험군에 따라 세 군(대조군, 방사선조사 단독군, melatonin 전처치군(방사선조사 1시간 전에 300 mg/kg 복강주사))으로 분류하고 양측 흉곽에 12 Gy의 선량을 단일조사하였다. 방사선조사 후 2주와 4주의 폐조직에서 TGF-β1 mRNA 발현수준을 측정하기 위해 semiquantitive RT-PCR를 시행하였고, TGF-β1 protein 발현의 수준과 위치를 보기 위해 면역조직화학염색을 시행하였다. 결 과: 2주 후에 측정된 mRNA 발현은 방사선조사 단독군과 melatonin 전처치군에서 각각 대조군의 1.92배와 1.80배 증가된 수준을 보였고(p=0.064), 4주 후에는 각각 2.38배와 1.94배 수준의 증가된 발현을 보였다(p= 0.004). TGF-β1 protein의 발현은 조직병리학적으로 방사선손상 영역에서 주로 관찰되었는데 폐포 대식세포와 폐포벽의 상피세포들이 주요 근원이었다. 발현수준은 2주와 4주 후에 각각 15.8% vs 16.9% (p=0.565), 그리고 36.1% vs 25.7% (p=0.009)이었다. 결 론: Melatonin 전처치로 방사선조사에 의한 TGF-β1 mRNA와 protein의 발현이 4주 후에 유의하게 감소됨을 관찰하였다. 따라서 방사선으로 인한 폐손상 시에 항섬유증 약물로의 사용가능성을 확인하였다.

다국어 초록 (Multilingual Abstract)

Purpose: The changed expressions of TGF-β1, as a key cytokine in the fibrotic process, due to melatonin with potent antioxidative effects, were investigated in the irradiated lung using fibrosis-sensitive C57BL/6 mice.
Materials and Methods: Female C57BL/6 mice were divided into control irradiation-only, and melatonin (300mg/kg i.p. 1 hr before irradiation) pretreatment groups. The thoraces of the mice were irradiated with a single dose of 12 Gy. The mRNA expressions of TGF-β1 in the lung tissue 2 and 4 weeks after irradiation were quantified using semiquantitive RT-PCR, and the cellular origin and expression levels of TGF-β1 protein were identified using immunohistochemical staining. Results: The relative mRNA expression levels in the irradiation-only and melatonin pretreatment groups 2 and 4 weeks after irradiation were 1.92- and 1.80-fold (p=0.064) and 2.38- and 1.94-fold (p=0.004) increased, respectively compared to those in the control group. Increased expressions of TGF-β1 protein were prominently detected in regions of histopathological radiation injury, with alveolar macrophages and septal epithelial cells serving as im portant sources of TGF-β1 expression. At 2 and 4 weeks after irradiation, the expression levels of protein were 15.8% vs. 16.9% (p=0.565) and 36.1% vs. 25.7% (p=0.009), respectively. Conclusion: The mRNA and protein expressions of TGF-β1 in the lung tissue following thoracic irradiation with 12 Gy were significantly decreased by melatonin pretreatment at 4 weeks. These results indicate that melatonin may have a possible application as an antifibrotic agent in radiation-induced lung injury.

목차 (Table of Contents)

• 서 론
• 대상 및 방법
• 결 과
• 고안 및 결론

참고문헌 (Reference)

• 1 "Transforming growth factor β in tissue fibrosis" 1286-1292,
• 2 "The effect of melatonin on bleomycin-induced pulmonary fibrosis in rats" 32 : 21-25, 2002
• 3 "TGF-β1 and radiation fibrosis: a master switch and a specific therapeutic target?" 47 : 277-290, 2000
• 4 "Radiation-induced lung injury in vivo expression of transforming growth factor-beta precedes fibrosis" 20 : 339-352, 1996
• 5 "Radiation pneuminitis and pulmonary fibrosis in non-small-cell lung cancer: pulmonary function, prediction, and prevention" article in press 2005
• 6 "Plasma transforming growth factor β1 as a predictor of radiation pneumonitis" 41 : 1029-1035, 1998
• 7 "Pinealectomy-induced elevation of collagen content in the intact skin is suppressed by melatonin application" 100 : 49-55, 1999
• 8 "Oxidative damage and fibrogenesis" 22 : 287-305, 1997
• 9 "Normal tissue radiobiology: from the laboratory to the clinic" 49 : 353-365, 2001
• 10 "Melatonin: from basic research to cancer treatment clinics" 20 : 2575-2601, 2002
• 11 "Melatonin suppresses the pinealectomy-induced elevation of collagen content in a wound" 85 : 51-58, 1996
• 12 "Melatonin reduces dimethylnitrosamine-induced liver fibrosis in rats" 37 : 78-84, 2004
• 13 "Melatonin as a radioprotective agent: a review" 59 : 639-653, 2004
• 14 "Mechanisms of disease melatonin in humans" 336 : 186-195, 1997
• 15 "Mechanisms of TGF-β signaling in regulation of cell growth and differentiation" 82 : 85-91, 2002
• 16 "Increased survival time in brain glioblastomas by a radioneuroendocrine strategy with radiotherapy plus melatonin compared to radiotherapy alone" 53 : 43-46, 1996
• 17 "Dose-dependent induction of transforming growth factor β (TGF-β) in the lung tissue of fibrosis-prone mice after thoracic irradiation" 47 : 1033-1042, 2000
• 18 "Differences in correlation of mRNA gene expression in mice sensitive and resistant to radiation-induced pulmonary fibrosis" 142 : 197-203, 1995
• 19 "Cellular basis of radiation-induced fibrosis" 35 : 83-90, 1995
• 20 "Antioxidative effects of melatonin in protection against cellular damage caused by ionizing radiation" 225 : 9-22, 2000
• 21 "A perpetual cascade of cytokines postirradiation leads to pulmonary fibrosis" 33 : 99-109, 1995