Effect of Hyperbaric Oxygen on Tissue Damage and Expression of Adhesion Molecules and C3 in a Rat Model of Renal Ischemia-Reperfusion Injury After Kidney Transplantation.

BACKGROUND The aim of this study was to investigate the protective effect and mechanism of hyperbaric oxygen (HBO) in a rat model of renal ischemia-reperfusion injury following kidney transplantation. MATERIAL AND METHODS Sprague Dawley rats were randomly divided into 3 groups (n=18): sham group, kidney transplantation group, and HBO treatment group. Six rats in each group were sacrificed at 1, 3, and 5 hours after reperfusion, and serum and renal tissue were then collected. The serum creatinine levels and histopathological changes of the renal tissue were detected. ICAM-1, VCAM-1, and C3 expression levels were also detected by immunohistochemical staining or real-time polymerase chain reaction. RESULTS Renal function was damaged in the kidney transplantation group and the HBO treatment group compared with sham group (P<0.05). Renal histopathological changes, including tubular cell swelling, tubular dilatation, and hyaline casts, were remarkably reduced in the HBO treatment group compared to the kidney transplantation group. In the immunohistochemical examination, the expression levels of ICAM-1, VCAM-1, and C3 were obviously increased in the kidney transplantation group and the HBO treatment group; moreover, the levels in the HBO treatment group were significantly lower than in the kidney transplantation group (P<0.05). In addition, the ICAM-1 and C3 mRNA levels were increased in the kidney transplantation group and HBO treatment group, but the levels of in the HBO treatment group them were significantly decreased compared to the kidney transplantation group that at 3 and 5 hours after reperfusion (P<0.05). CONCLUSIONS HBO treatment exerted a protective effect on renal function through inhibition of adhesion molecule overexpression and complement system activation in a rat model of renal ischemia-reperfusion injury after kidney transplantation.

Hyperbaric Oxygenation Protects Against Ischemia-Reperfusion Injury in Transplanted Rat Kidneys by Triggering Autophagy and Inhibiting Inflammatory Response.

BACKGROUND Ischemia-reperfusion injury (IRI) is a clinically common pathologic process defined as the inability to improve neuronal function. This study aimed to investigate the pathological mechanism of IRI and to explore effects of hyperbaric oxygenation (HBO) on autophagy and inflammatory response in IRI. MATERIAL AND METHODS Ninety Sprague-Dawley (SD) rats were randomly divided into a Sham group, a kidney transplant group (Trans), and a kidney transplant plus HBO treatment group (Trans+HBO). The kidney was harvested from the donor and transplanted to recipient rats according to a previously reported study. Rats were anesthetized using pentobarbital-natrium, and the kidney was resected and fixed in 4% paraformaldehyde. Serum creatinine (Scr) was detected using an automatic biochemical analyzer. The interleukin-6 (IL-6) level was assessed using enzyme-linked immunosorbent assay (ELISA). LC-3 was examined using indirect immunofluorescence assay and immunochemistry assay. LC-3 mRNA levels were analyzed using real-time PCR (RT-PCR). RESULTS The kidney transplant IRI model was successfully established. Scr and IL-6 levels were significantly increased in the Trans group (P<0.05). HBO significantly enhanced Scr and IL-6 levels. Scr was positively correlated with IL-6 levels (r-0.607, P<0.05). HBO increased LC-3 protein and mRNA expression in kidney-transplanted rats compared to the Sham and Trans group (P<0.05). Moreover, immunofluorescence assay also showed that LC-3 protein mainly distributes along renal tubular epithelial cells in a linear manner. CONCLUSIONS Autophagy dysfunction and inflammatory response after renal transplantation play important roles in processes of IRI. HBO treatment protects against the renal injury of IRI in renal tissues at the early stage, which may be triggered by the IL-6 pathway.