The Relationship Between The Changes Of TGFβ₁,NO,Blood Distribution Of Both Lung, DVHS And Radiative Lung Injury

ObjectiveLung are very sensitive to radiation,therefore they are one of the main organs that restrict the increasing radio - therapeutic dose for tumors in chest,resuiting in greatly reducing the radio -therapeutic effectiveness for the chest tumors.Beactions to the radioactive rays of the lungs are caused by many influencing factors:they are constrained from the changes of some cell factors,and at the same time closely related to the radiated volume and the radiated dose as well.In the research,through the animal model with radiated lung injury,we would observe the happening and developing course of the radiated lung injury, the dynamic changes of TGFβ₁,NO and the blood-flux in both lung.We would analyse the independency and the inter-relations among these influencing factors and evaluate comprehensively the affections of radiative volume,dose and basic lung functions on the occurrence rates of radiative lung injury through chest tumor patients undergoing radiation.Methods1.Experimental animal group:Assigned randomly 40 big-eared white rabbits into group A(control group) and group B(L-argnine group),the whole left lungs of all were radiated with 6MV X rays,and the radiated dose is 25Gy/each time.Animals in group A are fed with normal fodder,while animals in group B started to be fed with L-argnine contained fodder one month after radiotherapy.Every five in group A are executed respectively after the first,the second,the third,the forth and the sixth month of radiotherapy,while another each - five in group B are executed respectively after the fast,the third,the sixth month of radiotherapy. Before the execution,the animals in both groups respectively receive lung blood -flux scanning,blood sampling in LV and flushing in left lung.The flushing liquid were preserved at -20℃in a refrigerator.After the execution,the animals' left lung were taken out and put into Formalin solvent for stabilization. Tested the amount of TGFβ1 contained in the lung flushing liquid using ELISA method;tested the amount of NO₂^-/NO₃^- contained in blood plasma using Cdcu method;tested the amount of iNOS contained in left lung using immunization grouping method;observed the pathological changes of the lung under a microscope.2.Clinical experimental group:Randomly 55 cases of the lung - cancer patients were radiated with 6MV X rays and the dose were 2-3Gy/each time/per day,then the different radiated dose of different percentage of each patient were worked out using DVHS graphs in three - dimensional plan system.Three to six months after the radiotherapy,a CT checkup in lungs was needed to confirm if there was any fibrosis in the radiative lung so as to comment on the relationship between lung fibrosis and the radiated dose and volume.Results1.Experimental animal group1.1 Changes of the TGFβ1 and two -sided lung blood flux in both group A and B tend to be nearly the same.The amount of TGFβ1 appeared to be obviously climbing up within 1-6 months after the radiotherapy;and the highest amount appeared in the second and the sixth months after the radiotherapy, whereas the percentage that the left lung took upon in the whole obviously came down in 1-6 months after the radiotherapy,and the lowest amount appears in the first and the third months.1.2 The amount of NO2 -/NO3 - went up obviously one month after the radiotherapy in the group A and group B.While in 3-6 months after the radiotherapy, the amount in group A went apparently down,however,even if the amount in the group B went down as well,yet it was still higher than it was before the radiotherapy.The iNOS protein expression in lung of both groups appeared the same performances,that was,before or 3 - 6 months after the radiotherapy, small quantity of iNIS expressions in cells were found to be positive.In the first month after the radiotherapy,positive iNOS protein expressions cells in the lung medium increased apparently.1.3 Pathological changes of lung after radiotherapy:1-3 months after the radiotherapy,it showed grade 1-2 changes in both group A and group B.In the sixth month after the radiotherapy,all the animals in the control group showed grade 3-4 changes,whereas among the five animals in group B,although four of them showed grade 3 changes,the fibrosis was slight and the other one basically appeared normal under the lens.2.Clinical experimental group:among the 55 cases,15 cases showed radiative lung fibrosis proved by CT,took 27.3%.DVHS results indicated:when the radiated volume over 30%of the ipsilateral lung or 25%of the whole lung, the radiative lung fibrosis occurrence rate would abruptly go up.Conclusion1.The dynamic changes of TGFβ1 is in compliance with the happening and developing course of the radiative lung fibrosis,so it can be considered as one of the reasons for it.2.NO obviously goes up during the early radioactive period (in the first month) and dramaticly decrease in 3-6 months are independent influencing factors for the fibrosis.Outsourcing L - argnine can reduce the occurrence rate of the radiative lung fibrosis of the experimented animals.The decrease of NO level after the radiotherapy is related to the decrease of the NOS protein activity.3.After the radiotherapy,the blood-flux of the radiated lung reduced apparently.4.The occurrence of radiative lung fibrosis is related to the radiated volume and dose.When the radiated volume reaches 25%of the whole lung,the radiated dose should not be more than 20Gy;when the radiated volume reaches 25%of the ipsilateral lung,the radiated dose should not be more than 30Gy.