Dynamic Changes And Significance Of Keratinocyte Growth Factors In Kidneys Of Sepsis Rats

Sepsis is a systemic inflammatory response that the organism was infected by a variety of pathogenic micro-organisms or their toxins presented in blood or tissues,and may lead to an organ damage and even a multiple organ dysfunction syndrome (MODS).The kidney is one of the most vulnerable organs in sepsis,and early intervention to sepsis with acute renal injury should not be ignored in the treatment of sepsis.Keratinocyte Growth Factors(KGFs) belong to the Fibroblast Growth Factor family(FGFs),which is a kind of important heparin-binding peptides.At present,there are two members called KGF-1(also known as FGF-7) and KGF -2(also known as FGF-10).They are producted by the mesenchymal cells,and may specifically stimulate the epithelial cells to proliferate in autocrine or paracrine manner,and are concerned with the development of organs and homeostasis.To various types of epithelial cells, KGF is an effective and specific mitogen,which can protect cells from a variety of injuries and play an important role in the repair of damaged epithelial tissue.Now, studies on expression and significance of KGF in the mouth,mucous membrane and middle ear cholesteatoma designate,as well as in acute lung injury,radiation damage and intestinal tumor et,al have been reported.Relative report on expression and distribution of KGF in damaged kidneys of sepsis as well as on repair have not been found.By establishing a sepsis rat model,the dynamic changes and significance of KGFs in damaged kidney of sepsis have been found and part of the mechanisms about the repair of injuried kidneys in the pathological process of sepsis have been explored.Methods80 male WISTER rats were divided into two groups randomly.40 in the sepsis group(group A) and 40 in the sham operation group(group B).Sepsis models were made through the traditional operation named CLP.3/6/12/24/36 hours after operation,samples were taken from group A and group B respectively to observe pathological changes as well as to detect Cr,BUN and white corpuscles in blood plasm. Immunohistochemistry in paraffin section was used to detect KGFs proteins and Real Time PCR to detect KGFs genes in kidney tissue of all samples.All experiments were repeated more than 3 times,using SPSS 15.0 statistical software for statistical treatment.Measurement data was expressed with mean±standard deviation,One-way ANOVA,t- test and pearson correlation analysis were used as statistical methods with P＜0.05 as statistical significance.ResultsFirstly,under naked-eye observation,the kidneys in group A were dark red,and turned out to be punctiformly or lamellarly blooded,relatively hard and less elastic at 24 hours after operation,which in group B were congestive,hydropic slightly with reasonable elasticity.Secondly,the renal tubules in group A were infiltrated by considerable neutrophilic granulocytes,leukomonocytes and mononuclear cells,with vacuolar degeneration,local petechia and necrosis under the light microscope at 24 hours after operation.However,there was little pathological change in group B contrasted to normal kidneys.Thirdly,both Cr and BUN in group A increased obviously than that of group B except at the point of 3 hours after operation.Fourthly,KGFs were expressed in both of the two groups,mainly in renal medulla and also in tubules of renal cortex.The cytoplasm of tubule epithelial cells was dyed,brown and yellow particles were visible under a microscope.Immunohistochemistry results showed that except in 3h point,the average optical at all time points in group A was significantly higher than that of group B(P＜0.05),with the peak value at 6 hours after operation.Compared with group B,the expresstion of KGF-2 in group A increased obviously at 12/24/36 hours after operation.Last,results of Real -Time PCR indicated that there was no significant difference of the relative copies of KGF-1mRNA between the two groups at 3h point and that of KGF-2mRNA at 3/6 hours after operation(P＞0.05).However,at other time points,both KGF-1mRNA and KGF-2mRNA are expressed much more in group A than in group B.KGF-1mRNA was positively correlated with BUN(r=0.504,P=0.001＜0.01)and so was KGF-2mRNA(r=0.426,P=0.006＜0.01).KGF-1mRNA was positively correlated with Cr(r=0.382,P=0.015＜0.05) and so was KGF-2mRNA(r=0.555,P=0.000＜0.01). Conclusions1.KGFs were expressed in normal rat kidneys,mainly in tubule epithelial cells of renal medulla and also in that of renal cortex.Though the expression of KGF-1 was obviously higher than that of KGF-2,with earlier increase and longer persistence,it was not enough to say that the former was more important than the later in damage-repair mechanism.2.The expression of KGFs in sepsis group was obviously higher than that of sham operation group,and was positively correlated with the degree of kidney damage after infection.KGFs were speculated to be one of the protective factors influencing the repair of impaired kidneys caused by infection.