| Background:Kidney transplantation is the most effective treatment for end-stage renal disease patients who need dialysis,which helps to improve life quality and offer prolonged survival for them.Up to now,there are many kinds of effective immunosuppressive agents used for renal transplantation,which exhibit powerful ability on inhibiting the acute rejection during the whole process of kidney transplantation.However,there are still some adverse factors which are difficult to deal with during this process,one of them is ischemia/reperfusion injury.It is known that IRI is induced by the ischemia that occurs after blood flow recovery and restoration to tissues and organs,which further aggravates the injury.It has been identified that IRI is relevant to increased incidence of acute rejection and decreased long-term allograft survival,and it's considered as one of the important causes of early allograft dysfunction.Therefore,It is needed to pay more attention to finding the effective measures to protect the kidney from ischemia/reperfusion injury.This issue is an important question which worthes exploring.The pathogenesis of renal ischemia-reperfusion injury is complex and not yet fully elucidated.The current research data shows that the pathophysiological mechanism of renal ischemia-reperfusion injury may be related to the production of oxygen free radicals,inflammatory mediators,Ca2+ overload and cell apoptosis.Ozone is a powerful oxidizing gas,which is commonly used as a disinfectant in water and food industries.Although ozone is a potentially toxic agent,it can modulate many biochemical pathways at low and controlled nontoxic doses.Medical ozone therapy is a treatment of delivering a mixture of gaseous ozone and oxygen to the biologic systems.It has been identified that ozone therapy can be useful in treating inflammation-mediated diseases,such as infected wound,burns,and advanced ischemic diseases.Ozone therapy also shows the effect to resistant against oxidative stress by inducing antioxidant systems.Furthermore,it has been reported that ozone oxidative preconditioning has protective effect on ischemia reperfusion injury in liver and kidney.Nevertheless,ozone oxidative preconditioning has not been used previously in the homologous kidney transplantation in rat model.Therefore,the current study aimed to focus attention on the possible effect of ozone oxidative preconditioning on ischemia/reperfusion injury in homologous kidney transplant in rat model.Objective:To investigate the effect and mechanism of ozone oxidative preconditioning on the model of orthotopic kidney transplantation in SD rats.Methods:36 male SD rats were purchased from Tongji Medical College of Huazhong University of Science and Technology.All the SD rats were randomly divided into three groups:sham group,kidney transplantation group(KT group),ozone oxidative preconditioning group(OOP+KT group).Each group contains 12 SD rats,including donor rats 6,recipient rats 6.Sham group:rats were treated with opening the abdominal cavity,freeing left kidney,closing abdomen;KT group:SD rat received the donor's left kidney derived from another SD rat;OOP+KT group:before the kidney transplant procedure,donor rats received 15 OzoneOP treatments by transrectal insufflations(lmg/kg),once a day,at an ozone concentration of 50 ?g/ml.At the end of the 15th day,homologous renal transplantation between SD rats were done.Part I:To evaluate the effect of ozone oxidative preconditioning on the levels of serum creatinine(Cr)and blood urea nitrogen(BUN).The pathological changes of transplanted kidneys were observed by HE and PAS staining.Part II:To evaluate the effect of ozone oxidative preconditioning on the oxidative stress injury during kidney transplantation by detecting the expressions of Nrf-2 and HO-1 in kidney tissue,also levels of MDA SOD,GSH,GSH-Px and CAT activity.Part III:To evaluate the effect of ozone oxidative preconditioning on the inflammatory reaction during kidney transplantation by detecting the expressions of HMGB1 and NF-KBp65 in kidney tissue and the serum levels of IL-6,IL-18,TNF-a and COX-2.Part IV:To investigate the effects of ozone oxidative preconditioning on the expression levels of Caspase-3,Bcl-2 and Bax in kidney tissue and the apoptosis of renal tubular epithelial cells during kidney transplantation by TUNEL.Results:1.The results of renal function showed that the serum levels of BUN and Cr in group OOP+KT were significantly lower than those in KT group,which indicated that ozone oxidative preconditioning was benefitial to the recovery of renal function.2.The results of HE staining,PAS staining and Jablonski showed that the histopathological damage of transplanted kidney in OOP + KT group was significantly alleviated and the pathological score was significantly decreased compared to those in KT group,which indicated that ozone oxidative preconditioning could attenuate the histopathological damage of renal allograft during renal transplantation.3.The results of oxidative stress pathway showed that the expression levels of Nrf-2 and HO-1 in OOP+KT group were significantly higher than those in KT group,which indicated that ozone oxidative preconditioning could up-regulate the expression of antioxidant system-related proteins.Besides,the activities of SOD,CAT,GSH and GSH-Px in OOP+KT group were significantly increased compared with those in KT group(P<0.05),while the levels of MDA was significantly reduced(P<0.05),indicating that ozone oxidative preconditioning could enhance the activities of oxygen free radical scavenging enzymes to increase oxygen free radical scavenging and alleviate renal damage induced by oxidative stress during kidney transplantation.4.The results of inflammatory reaction showed that the expression levels of HMGB1 and NF-?Bp65 in OOP+ KT group were significantly decreased compared with those in KT group.Besides,the serum levels of IL-6,IL-18,TNF-? and COX-2 in OOP+ KT group were obviously lower than those in KT group.Those results indicated that ozone oxidative preconditioning could reduce the inflammatory response in renal allograft and peripheral blood during renal transplantation.5.The results of TUNEL showed that the number of renal tubular epithelial cells apoptosis in OOP+KT group was significantly decreased compared with KT group(p<0.05).The expression levels of Caspase-3 and Bax in OOP+KT group were much lower than those in KT group;Meanwhile,the expression level of Bcl-2 in OOP+KT group was much higher than that in KT group,which indicated that ozone oxidative preconditioning could reduce the apoptosis of renal tubular epithelial cells during renal transplantation.Conclusion:1.Ozone oxidative pretreatment could protect the renal function of recipient rat and alleviate the morphological damage of the transplanted kidney in the model of orthotopic kidney transplantation between SD rats.2.Ozone oxidative preconditioning could up-regulate the expression of antioxidant system-related proteins and enhance the abilities of anti-oxidative stress in the transplanted kidney.3.Ozone oxidative preconditioning could attenuate the inflammatory response in transplanted kidney tissue and reduce the release of inflammatory factors in peripheral blood in the model of orthotopic kidney transplantation between SD rats.4.Ozone oxidative preconditioning could reduce the apoptosis of renal tubular epithelial cells in transplanted kidney of recipient SD rats. |
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