Research On The MRNA Of NF-?B P65?I?B??IL-1? In Radiation-induced Lung Injury

Objective To investigate the mRNA of NF-?B p65?I?B??IL-1?in radiation-induced lung injury?RILI?,and to reveal the molecular mechanisms involved in the occurrence and development of radiation-induced lung injury.Methods sixty-four male Sprague-Dawley rats?SD rats?were randomly divided into two groups according to the random number table method:Blank group?group A?and and 18 Gy Irradiation group?group B?,Each group has 32 rats.Rats in the blank group were only fed without other treatments;rats in the experimental group were irradiated with a single large dose?18 Gy?to the right lung.The models of RILI in SD rats were using ⁶⁰Co?therapeutic machine.Two groups of rats were divided into 4 subgroups.Eight rats from each subgroup were sacrificed,serum and lung tissue were collected after anesthesia on the 2th,6th,12th,and 24th weekends:?1?The observation by naked eyes were used to observe the changes in lung tissues of rats;?2?Serum levels of inflammatory cytokines IL-1?were measured by enzyme-linked immunosorbent assay?ELISA?;?3?Right hepatic tissue was observed by hematoxylin-eosin?HE?staining and Masson staining?Masson staining?.Pathological changes;?4?Determination of hydroxyproline content in homogenate of lung tissue by alkaline hydrolysis;?5?Quantitative reverse transcriptase polymerase chain reaction?q RT-PCR?detection of NF-?B p65,I?B?,IL-1?mRNA relative expression level.Results?1?The observation by naked eyes of rat lung tissues:Rats in the blank group at each time point showed a pinkish,a soft,full,elastic,smooth,and non-inflammatory exudate in lung.In the irradiated group,mild edema appeared in the lungs from the 2th weekend.At the end of the 6th week,the lung tissue further swollen.By the end of the 12th week,the lung tissue of rats gradually became atrophic and the texture became tough.At the end of the 24th week,the lung tissue of the rats was atrophic and the surface was uneven,you can see obvious grayish white areas in the lung tissue.?2?HE and Masson staining showed that there was no obvious congestion,edema and other pathological changes in alveolar and pulmonary interstitial tissues in the right lung tissue of the blank group.The structure of the alveoli was intact,and the deposition of collagen fibers was not obvious in the blank group.At the end of2 weeks after irradiation,lung tissue appeared mild hyperemia,some alveolar epithelial shedding,and slight interstitial edema.At the end of 6 weeks after irradiation,the alveolar wall and alveolar septum thickened slightly,alveolar space narrowed slightly,and edema was evident,accompanied by inflammatory cell infiltration and deposition of a few collagen fibers;at the end of the 12th week,the thickness of the alveolar wall and alveolar septum was more obvious than before,local alveolar disappeared,alveolar wall and septum appeared obvious proliferation of fibroblasts,fibroblasts,collagen,etc,and the deposition increased earlier;at the end of the 24th week after irradiation,some alveolar cavities were replaced by connective tissue,fusion,substance,some alveolar cavities disappeared,the lung structure was destroyed by connective tissue,the alveolar wall was significantly thickened,and a large number of fibroblasts proliferated,in place of local normal tissue,collagen fibers are significantly deposited.?3?Quantitative determination of hydroxyproline in lung tissue:there was no significance among subgroups of group A in hydroxyproline level.While the hydroxyproline level was exhibited slightly increase in group B at 6th week,with 24th week at its peak.?4?ELISA:there was no significant difference in the content of IL-1?in subgroups of group A?P>0.05?.IL-1?level in group B was significantly higher than that of group A.The expression of IL-1?in group B gradually increased at 2th and 6th week,which fell at 12th and 24th week.?5?q RT-PCR:there was no significant difference in the relative expression of NF-?B p65,IL-1?between blank groups?P>0.05?.The expression of mRNA containing NF-?B p65?IL-1?in group B was significantly higher than that of group A?P<0.05?,IL-1?with 6th week at its peak?P<0.05?,NF-?B p65 with 12th week at its peak?P<0.05?.The expression of mRNA containing I?B?in group A was significantly higher than that of group B?P<0.05?,with 12th week at its peak?P<0.05?.Conclusion The model of radiation-induced lung injury can be effectively established by using a medical 60Co radiation therapy instrument to perform a single irradiation of 18 Gy in rats'right lung.Serum IL-1?is involved in the development of radiation lung injury,and plays a major role in the early stage of radioactive lung injury.In the process of radiation-induced lung injury in rats,the relative expression of NF-?B p65,IL-1?mRNA was up-regulated and the mRNA expression of I?B?was down-regulated.