| PrefaceLung tissues often receive defined doses of radiotherapy during radiation therapy for thoracic tumor, resulting in some degree injury.Radiation - induced lung injury is sever sequelae for radiotherapy of cancer, the mechanisms leading to pulmonary fibrosis is still unclear. Some reported radiation lung injury may arise depending on the total dose of radiation given, the fractionation schedule, the volume of lung irradiated, the existence of prior lung disease, and the use of chemotherapeutic drugs in the management of the disease. But it can' t explain why some people develop symptomatic radiation pneumonitis , whereas others don ' t develop. Therefore it limits many apply of irradiation in cancer treatment. Transforming growth factor 1 ( TGF - 1 ) is a multifunctional regulator of cell growth. Some studies showed in irradiation damage of normal tissues transforming growth factor 1 may play a important role. The aim of this study was to investigate the relationship of TGF - 1 expression in plasma with the irratiation injury of lung tissues of nonnal mice, so that it can guide to formulate the radiotherapeutic plan.Materials and MethodsWistar adult male mice were purchased from China Medical University Animal Laboratory.The mice were divided four groups by random. The former third were radiation groups, and the fouth group was contrast group. The former third groups mice were irradiated 10Gy,20Gy and 30Gy respectively. The irradiation characteristics were as follows; beam energy:6MV - photons; dose - rate:2Gy/min; source surface distance( SSD) : 1 m; size of the radiation field: 2.5 1. 5cm, in-eluding the whole right lung .TGF - 1 analysis;The big mouse single_antibody was provided by R&D system company. An enzyme_immunosorbent sandwich assay(ELISA) was used to quantify TGF - 1. The 96 - well microtiter plates were read at 450nm using an automatic plate reader.ResultsThe clinical symptoms of radiation damage.The main symptom after radiation was short of breath, the acceleration of respiratory frequency. The damage symptom in the 10 Gy group was not obvious while, it was evident in the 20Gy and 30Gy groups. The extent of damage is relative to the radiation dose. The higher the dose, the earlier and severer the damage were.The results of plasma TGF - 1 levels with the addition of irradiation dose and prolong of the time , the level of the plasma TGF - 1 elevate. Plasma TGF- 1 of post radiation were higher than pre - radiation. The difference is significance. Among the different dose point groups ,the difference is not significance.DisscussionRadiation - induced lung damage is a severe complication of radiotherapy. Which include pneumotis and fibrosis. They are two different phase of the disease . after a bulky dose of radiation, the early change of the lung tissue is permeation due to the increased alveolar permeability result from radiation. The character of radiation induced pneumonitis is the lack of surfactant that result in collapse of blood vessul into the alveoli or bleeding. The second phase of radio- pneumonitis is fibrosis, which may further induced the loss of lung function and lead to death.Transforming growth factor 1 is a multifunctional regulator of cell growth and differentiation that is widely expressed in both normal and malignant tissue.This cytokine is released into either tissues or the circulation in latent form that has no biologic effect until it is activated. Thus,an elevated level of latent TGF- 1 in the circulation has no adverse effect on patients. It is only when this TGF - 1 is activated that problems related to excessive fibrosis can occur.Radiation - induced lung damage in experimental animals is a very complicated process. A number of authors have studied the mechanism of the damage. Adanson believed that a control system of the epidermis - fibroblast in the lung regulate the metabolism of fibroblast which involve in the repair of lung tissue and don' t generate over control to the extrem to lung fibrosis. Ru... |
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