Objective To observe the protective effect of N-NAC on radiation-induced lung injury. Methods 86 cases of thoracic neoplasm patients were chosen and randomly divided into two groups,group RT +N(n =43)and group RT(n =43).Two groups were observed by CT after radiotherapy.Acute and chronical toxicities were graded by RTOG.TGF-β1,IL-1,IL-4,TNF were observed before and after the radiotherapy.Results After 3 monthsof radiotherapy,RTOG≥2 was 23.4%(RT +N),while RTOG≥2 was 53.1%(RT).there was significant differencebetween the two groups(P <0.01).At 6,9 and 12 months,fibrosis was present in 28.4%,25.4%,22.4% receivingRT vs 58.4%,54.4%,52.4% receiving RT +N,there was significant difference between the two groups(P <0.05).TGF-β1,IL-1,IL-4,TNF were observed which showed that The RT +N were lower than RT.Conclusion N-NAC can reduce incidence rate of lung injury in radiotherapy,and can reduce the content and the release of TGF-β1,IL-1,IL-4,TNF.

Objective To clone the cDNA encoding human HMGB1, express it in E. coli, and identify its biological activity. Methods Human HMGB1 cDNA was amplified by RT-PCR and cloned into vector pUC19. After sequence analysis, the cDNA was ligated into prokaryotic expression vector pQE-80L and induced by IPTG to express HMGB1. The protein was purified with Ni~(2+)-NTA chromatography and polymyxin B affinity column. To identify the function of purified protein, the product was co-cultured with THP1 cells. Results Recombinant expression plasmid pQE-80L/HMGB1 was constructed successfully. After purification, the protein purity reached 96%. The recombinant HMGB1 stimulated THP1 to secrete TNF-? . Conclusion The highly purified HMGB1 was obtained successfully, which showed biological activity. These results lay the foundation for further research on the function of human HMGB1.