Expression Of Interukin-22 And Its Receptor In Rat Klebsiella Pneumoniae

BackgroundIL-22 is an IL-10 family cytokine member that was recently discovered to be produced by Th1,TH17andTH22 cells. Current studies have revealed that IL-22 targets cells of the digestive, skin, and respiratory organ systems and plays an important role in mucosal immunity. The IL-22 receptor (IL-22R) is expressed exclusively in these tissues, thereby allowing the cytokine to mediate epithelial innate immunity in response to a variety of pathogens. Although recent studies have shown the importance of IL-22 in host defense against Gram-negative bacterial organisms in gut and lung.The change of IL-22 and its receptor expression in klebsiella pneumoniae is not clear.This study will investigate expression of the IL-22 and its receptor in the progression of pneumonia.Part one : Establishment of rat model with pneumoniaObjectiveTo Established Klebsiella pneumoniae pneumonia of SD rats model through injection standard Klebsiella,thereby we explore the expression of IL-22and its receptor with this model.Method50 Sqrague-Dawley rats were randomly divided into 2 groups, pneumonia group and control group. Each groups contains 25 rats, Pneumonia group and control group according to the time of animals were killed, it were divided into 5 groups. Through intraperitoneal injection of 10% chloral hydrate 400mg/kg fixed after anesthesia, sterile hole shop towel in SD rats . We disinfecte the neck,preparate aseptic skin, cut the neck skin, expose the trachea. Through the trachea into 0.2mL bacterial suspension (concentration 0.9×109 CFU / mL), the control group equal volume of sterile saline drip. The erection of rats immediately after inoculation is keeped upright for 20 seconds. to ensure uniform distribution of bacilli in the lungs. After inoculation 4h, 1d, 2d, 3d, 4d experimental animals we sacrifice in batches anesthesia. Each rat lung was taken for colony counts of lung tissue and pathological examination. According to bacteriological and pathological indicators, we evaluat the model of establishment of pneumonia. (1) Pathological examination: We take the lower left lung, through 10% formalin fixe,slice and stain with HE the lung.We use microscope to observe the lung tissue of the pathological changes. (2)Bacteriology: We select three rats of the left upper lung tissue in Each team randomly, weigh, put the tissue in ice bath at 4℃, we dilute the lung tissue to 106. The concentration of homogenate has taken 0.02ml by respectively and has inoculated in blood agar plate.We taked the blood agar plate into 35℃incubator and incubated for 24 h,.We selected colonies at between 30 and 300 plates for counting.Results1. Rats after inoculation of pneumonia showed decreased activity, gathered the group, refused to eat, vertical hair, stimulate reflection of poor.However control group were not.2. Pathology: Pneumonia group generally showed bilateral lung leafy significant hyperemia, hemorrhage and edema, and microscopic alveolar structural damage, alveolar and interstitial edema and congestion and a significant, significant neutrophil infiltration, the 3d Group is particularly evident.3. Homogenate colony counts: Bacteria in lung tissue of homogenate pneumoniae is ultured bacteria from the hospital room identification by system API bacteria colonies cultured verified whether all the standard strains of Klebsiella pneumoniae. Bacteria of pneumonia groups was the highest colony counts of 4 hours,.Bacterial counts was significantly deseased on 4 days group.Part two: IL-22 and its receptor IL-10R2 to the determination of the measured data and the relationship between lung colony count ofObjectiveMeasure IL-22 and IL-10R2 expression in different time periods of pneumonia group. Explore the changes of the control group and pneumonia group. Research the expression of different time periods and lung tissue between bacterial colony count .MethodsWe take the upper right pneumonia groups and control groups of lung, and use of RNA in the lung preservation solution stored at -80℃for real-time fluorescence PCR.we remove the cavity blood 2ml, 3000r/min switch to centrifugation for 20 minutes, leave the serum for the detection of IL-22 concentration.ResultsAfter modeling the pneumonia group, the expression of IL-10R2mRNA began to increase at 4h, reached a peak at day 3, the difference was statistically significant (P <0.01). The IL-10R2 of control group increase at day 1, day 2 compared with other groups. We consider this is trachea damage. P> 0.05.Pneumonia group and the control group is compared at the same time point, P <0.05, Pneumonia group on day 3 group with the other time groups is compared, P <0.05. Pneumoniae in peripheral blood of our group with the control group IL-22 is compared to at the same time point, P <0.05, pneumonia group 3 days 4 days with pneumonia group on day 1 is compared at 4h , P <0.05. Pneumonia group 4h and the group with pneumonia on day 1 day 2 groups is compared, P> 0.05. Pneumonia group3,4-day groups with the pneumonia group day 2 is compared, P> 0.05. At the same time IL-22 of pneumonia groups in peripheral blood and lung tissue colony count correlate negatively, R =- 0.587, P = 0.002. IL-10R2mRNA which express in lung of pneumonia with colony counts correlate negatively.R =- 0.64, P = 0.01.Conclusion:1.Through intratracheal instillation of Klebsiella pneumoniae bacterium we can successfully copy the rat model of Klebsiella pneumonia.2. IL-22 and IL-10R2mRNA which pressed in the rat model of pneumonia group is expensive.3.IL-10R2mRNA expression began to increase at 4h and peaked at day IL-10R2mRNA and colony counts of lung tissue at same time correlate negatively.IL-22 is eary inflammatory factors of pneumonia bacteria.4.IL-22 serum levels in pneumonia, the lowest at the 4h, started to increase on 2 day group.IL-22 in blood with colony counts correlate negatively.