Role Of Connective Tissue Growth Factor And Transforming Growth Factor-beta On Hyperoxic Lung Fibrosis In Neonatal Rats

Part I: The effect of various dosage of ectogenesis anti-TGF-β1 on hyperoxic lung fibrosis in neonatal rats Objectives: Hyperoxia is very useful in neonatal medicine, however, long-time hyperoxia inhalation may be make many actived hyperoxia,what causes acute lung injury(ALI),and develops into lung fibrosis-bronchopulmonary dysplasis(BPD). the pathogenesis of hyperoxic lung injury in neonate isn't understood completely now. We proposed to establish the neonatal rats model of hyperoxia-induced lung injury,and observe the dynamic changes of the pathologic alteration, and the expression level of TGF-β1 in the lung of neonatal rats exposed to the hyperoxia inhalation to try to explore:(1) Role of various dosage of ectogenesis anti-TGF-β1 on hyperoxic lung fibrosis. (2) Effect of the expressions level of TGF-β1 on hyperoxic lung fibrosis with various dosage of ectogenesis anti-TGF-β1. Methods:120 clean Sprague-Dawley(SD) rats which were less than 12 hours old were enrolled in this study.The rats were divided into 6 groups randomly: I normal air control group.Ⅱ>95%O2.Ⅲ>95%O2+anti-TGF-β10.1mg/kg. Ⅳ> 95%O2+anti-TGF-β1 0.2mg/kg. Ⅴ>95%O2+anti-TGF-β10.4mg/kg. Ⅵ>95%O2+anti-TGF-β1 0.8mg/kg. GroupⅠwere placed in the room air .Group Ⅱ,Ⅲ,Ⅳ,Ⅴand Ⅵwere placed into oxygen cabins and were exposed to >95% O2 72 hours,at same time,neonatal rats have nebulization therapy with various dosage anti-TGF-β1 3 days,one time everyday. After at 72 hours,7 days,14 days and 28 days of exposure to high concentration oxygen(O2>95%), the changes of the pathologic alteration in lung were measured,and the expression level of TGF-β1 were measured by immunohistochemistry. Results: The expression level of TGF-β1 increased at hyperoxia 72 hours and 7 day. Microvessel hyperemia, edema,inflammatory cell infiltration, hemorrhage were found by using light microscope. at hyperoxia 14 day, that edema,inflammatory cell infiltration,hemorrhage reduced,maked fibrosis changes in lung. At hyperoxia 28 day there were a obvious inflammation and wider alveolus alternation than other groups and strong express of TGF-β1 in group Ⅱ, Ⅲvand Ⅳ. There were no significant fibrosis increased at hyperoxia 14-28 day in group Ⅴand Ⅵ.Campared with the different control,the expression level of TGF-β1 was no increase at hyperoxia 14 day,it be a low level Lung structures was no disorder, no ECM and lung fibrosis was found bye using light microscope and transmission electron microscope. Conclusion: Hyperoxia can increase caused acute or chronic lung injury. Hyperoxia can obviously increase the expression level of TGF-β1,cause lung constitutions disorder and lung fibrosis, which indicates TGF-β1 was key role in fibrosis. anti-TGF-β1 inhibited the ALI and lung fibrosis. anti-TGF-β1 can against lung fibrosis and exceptional alveolus develop, which indicates TGF-β1 may have key role in hyperoxic-induced lung fiborsis. Key words: neonatal rats, hyperoxia,transformig growth factor-β1, antitransforming Growth factor-β1 Part II: Role of connective tissue growth factor and transforming growth factor-beta on HyperoxicLungFibrosis in Neonatal Rats Objectives: Hyperoxia is very useful in neonatal medicine, however, long-time hyperoxia inhalation may be causes lung injury, which can result in respiratory failure, and develops into lung fibrosis. There attached much attention of people in medical science. the pathogenesis of hyperoxic lung injury in neonate isn't understood completely now. TGF-β1 and CTGF correlated with lung auxano and fibrosis. We proposed to establish the neonatal rats model of hyperoxia-induced lung injury,and observe the dynamic changes of the pathologic alteration, TAOC and MDA level, and the expression level of TGF-β1 and CTGF in the lung of neonatal rats exposed to the hyperoxia inhalation to try to explore:(1) role of CTGF on hyperoxic lung fibrosis. (2) role of TGF-β1 on hyperoxic lung fibrosis. (3) CTGF and TGF-β1 on hyperoxic lung fibrosis.(3) GSH ntioxidant and anti-TGF-β1 can relieve hyperoxic lung fibrosis.Methods:160 clean Sprague-Dawley(SD) rats which were less than 12 hours old were enrolled in this study.The rats were divided into 4 groups randomly: Ⅰnormal air control group.Ⅱ>95%O2.Ⅲ>95%O2+GSH.Ⅳ>95%O2+ anti-TGF-β1. GroupⅠwere placed in the room air .Group Ⅱ,Ⅲand Ⅳwere placed into oxygen cabins and were exposed to >95% O2 3 days. After at 72 hours,7days,14days and 28days of exposure to high concentration oxygen(O2>95%), TAOC and MDA level,and the changes of the pathologic alteration in lung were measured. the expression level of TGF-β1 and CTGF were measured by immunohistochemistry. Results: The expression level of TGF-β1, CTGF and MDA level increased at hyperoxia 72 hours and 7 day,but TOAC level was low at hyperoxia 72 hours. Microvessel hyperemia, edema,inflammatory cell infiltration, hemorrhage were found by using light microscope. MDA and TOAC recovered to the control at hyperoxia 14 day, and that edema,inflammatory cell infiltration,hemorrhage reduced,maked fibrosis changes in lung. At hyperoxia 28 day there were a obvious inflammation and wider alveolus alternation than other groups and strong express of TGF-β1 and CTGF in group Ⅱ. There were no MDA level increased at hyperoxia 72 hours and no significant fibrosis increased at hyperoxia 14-28 day with GSH. anti-TGF-β1 could inhibit the increase of the expressions level of TGF-β1 and CTGF at group Ⅱ72 hours.Campared with the control,the expression level of TGF-β1and CTGF was no increase at hyperoxia 14 day,it be a low level.Lung structures was no disorder, no ECM and lung fibrosis was found bye using light microscope and transmission electron microscope. Conclusion:Hyperoxia can increase nitric oxide and caused acute lung injury and Bronchopulmonary dysplasia. Hyperoxia can obviously increase the expression level of TGF-β1 and CTGF,cause lung constitutions disorder and lung fibrosis, which indicates CTGF and TGF-β1 was key role in fibrosis.GSH inhibited the ALI and lung fibrosis. anti-TGF-β1 can against lung fibrosis and exceptional alveolus develop, which indicates TGF-β1 and CTGF may have key role in hyperoxic-induced lung fiborsis.