| Objective: To investigate the changes and influence of hyperbaric oxygenation treatment onthe expression of indoleamine2,3-dioxygenase (IDO) and interleukin-8(IL-8) in transplantedkidney tissue and blood through establishing an ischemia-reperfusion injury model inhomologous rat transplanted kidney. And make a further exploration to the pathogenesis in IRI.Material and Methods:90SPF Sprague-Dawley (SD) male rats were divided randomlyinto sham group, kidney transplantation group and HBO treatment group. The1h,3h and5hafter surgery were considered as time points in our study. Kidney transplantation group andHBO treatment group underwent kidney transplantation;1-hour-HBO treatment was given inHBO treatment group after modeling immediately and the2h and4h hour afterischemia-reperfusion. Without kidney transplantation, rats in sham group were received rightnephrectomy only. Rats in each group were killed at the1h,3h and5h randomly. Left kidneytissue and blood samples were taken. In order to observe pathological change, HE stain wasconducted in our study. Both mRNA and expression of IDO were examined byimmunohistochemistry, confocal laser scanning fluorescence microscopy and real-timequantitative PCR. The level of IL-8in serum was examined with enzyme-linked immunosorbentassay (ELISA).Results:1.Histopathological changes of kidney tissue: There was no histopathological changes in shamgroup.At the end of the1h, damages including congestion of renal interstitial vessels,enlargement of renal glomerulus, hyperplasia in intercapillary cells, swelling in renal tubularepithelial cells were observed in transplanted kidney group. At the end of the3h, swelling andgranular degeneration of renal tubular epithelial cells were observed. At the end of the5h,glomerular enlargement with neutrophil infiltration, expansion in tubular lumen, protein cast, red cast, conspicuous swelling and granular degeneration in epithelial cells were observed intransplanted kidney group. There was no difference between HBO treatment group andtransplanted kidney group at the end of the1h and3h. At the end of the5h, renal glomerulusstill enlarged,but neutrophil infiltration, swelling in renal tubular epithelial cells, expansion intubular lumen, protein cast and red cast decreased.2.Changes of renal function: At each time point including the1h,3h,5h after modeling,compared with the sham group, the levels of Serum creatinine (SCr) in kidney transplantationgroup and HBO treatment group increased significantly (P<0.05). Meanwhile, there was nosignificant difference for SCr level between kidney transplantation group and HBO treatmentgroup at the1h and3h after modeling (P>0.05). The level of SCr in HBO treatment groupdecreased significantly at the end of5h after modeling (P<0.05).There was no significantdifference among the rats in Sham group (P>0.05). The level of SCr in kidney transplantationgroup increased significantly from the end of1h to5h with time elongation (P<0.05).The levelsof SCr in HBO treatment group at the end of3h and5h were significant higher than the one atthe end of1h (P<0.05). Between the2time points including the end of the3h and5h aftermodeling, there was no significant difference (P>0.05).3. IL-8level in serum: At the end of the1h,3hand5h, compared with the sham group, the levelof IL-8in kidney transplantation group was significant higher at each time point(P<0.05).Comparing with sham group, the level of IL-8in HBO treatment group significantly increased atthe1h and3h time point, with no significant difference at the5thtime point. Comparing withkidney transplantation group, the level of IL-8in HBO treatment group has no significantdifference at the1sttime point and was obvious lower at the3h and5h time point(P<0.05).4. IDO gene expression in kidney tissue(1) The expression of IDO shown by immunohistochemistry assay: It is showed that IDOprotein expressed mainly in renal tubular epithelial cells. It is shown by semi-quantitativeanalysis through mean optical density that IDO expression had no difference at the end of1hhour after modeling among the three groups. There was also no significant difference in the3hhour after modeling between sham group and kidney transplantation group. IDO expressionsignificantly increased at the end of the5h in kidney transplantation group (P<0.05). Theexpression of IDO in HBO treatment group is lower than kidney transplantation group (P<0.05). (2) The expression of IDO shown by confocal laser scanning fluorescence microscopy: It isshown that green fluorescent spot considered as IDO expression could be distributed mainly inrenal tubular epithelial cell.(3) IDO mRNA expression: At the end of the1h, there was no significant difference for IDOmRNA in the three groups. Compared with sham group, there was no significant difference forIDO mRNA at the end of the3h in kidney transplantation group. However, the level of IDOmRNA at the end of the5h increased significantly in kidney transplantation group(P<0.05). Theexpression of IDO mRNA in HBO treatment group was significant lower than kidneytransplantation group, without difference in comparison with sham group.Conclusions:1. Inflammatory response occurred early after ischemia-reperfusion injury in kidney andmassive production of IL-8can aggravate ischemia-reperfusion injury.2. Over-expression of IDO may be an important mechanism to the aggravation ofischemia-reperfusion injury with the extension of time after ischemia reperfusion.3. Hyperbaric oxygenation obviously inhibits the expression of IDO and the production ofinflammatory factors after ischemic reperfusion in transplanted kidney aiming to protect therenal function. Inhibiting the expression of IDO genes in kidney tissue by hyperbaricoxygenation treatment is an another important molecular mechanism in preventing theischemia-reperfusion injury. |
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