A study for time sequential expression of IL-1 alphaand IL-6 after irradiation on rat lung / 대한내과학회지

ABSTRACT

BACKGROUND: One of the limitation during the irradiation of malignant tumor is hazard to normal tissue although it is important and effective tool for treating malignant tumor. We studied the role of interleukin-1 alpha (IL-1alpha) and interleukin-6 (IL-6) in the radiation-induced lung injury especially on fibrosis. METHODS: We irradiated right-side lungs of thirty Sprague-Dawley rats with single fraction of 20 Gy and then sacrificed the animals until 20th week at intervals of two weeks. Both irradiated and unirradiated lung tissues were stained hematoxilin and eosin, Masson trichrome, reticulin and immunohistochemical staining for IL-1alpha and IL-6. The degree of the staining for IL-1alpha and IL-6 were examined semiquantitatively. RESULTS: Two weeks after irradiation interstitial edema and capillary congestion appeared, followed by increase of the monocytes infiltration and proteinaceous material during 4th and 8th week. After eight weeks of irradiation, collagen and reticulin fibers were detected along alveolar wall. 12th to 20th week, fibrosis in interstitium, decreased number of alveoli and thickening of bronchial wall were observed. The degree of immunohistochemical staining for IL-1alpha and IL-6 was increased rapidly during the first three week and then decreased slowly, but remain incresed until 20th week. CONCLUSION: Our Study demonstrate the early and persistent elevation of cytokines IL-1alpha and IL-6 by immunohistochemical stain in rat lung following pulmonary irradiation. We think cytokines are produced immediately after irradiation, make collagen genes turn on and perisist until the expression of late effects become apparent pathologically and clinically.