The Influence And Mechanisms Of Atrovastatin On Peritubular Capillary Density Of UUO Mice By PI3K/Akt/eNOS Pathway

Objective: To investigate the influence and mechanisms of atorvastatin on peritubular capillary (PTC) density in unilateral ureteral obstruction (UUO) mice with renal interstitial fibrosis by phosphatidylinositol 3-kinase/protein kinase-B/endothelial nitric oxide synthase (PI3K/Akt/eNOS) pathway.Methods: 96 SPF female Kunming mice were randomly divided into 3 groups, N=32:â‘ U nilateral ureteral obstruction group (UUO group) were operated by ligating of right urter;â‘¡Sham operated group (Sham group) were dissociated right ureter only without obstruction;â‘¢UUO⁺Atrovastatin intervention group (ATO group) were operated by ligating of right urter; and then administrating with atrovastatin 5mg.kg^-1.d^-1 by an intragastric way up to death. Eight rats of each group were killed by cervical dislocation at 7,14,21,28 day after surgery, blood and tissue specimens from the right kidney were remaided:â‘ To analyze the level of serum urea nitrogen and creatinine.â‘¡The percentage of CD133⁺/VEGFR2⁺ cells in peripheral blood mononuclear cells was detected by flow cytometry.â‘¢Morphological changes of renal tissue were observed by HE and Masson staining and were investigated through light microscope, the method of tubulo-interstitial injury(TI)evaluation was used to evaluate the degree of tubular damage and renal fibrosis.â‘£Immunohistochemistry was performed on right renal for protein kinase-B,phosphorylation protein kinase-B and endothelial nitric oxide synthase.⑤Immunohistochemistry was performed to investigate the expression of CD34⁺ cells in peripheral blood mononuclear cells to evaluate PTC density.Results:â‘ T he level of serum urea nitrogen had no apparent changes during the whole experiment, no statistical significance existed among the three groups.â‘¡The percentage of CD133⁺/VEGFR2⁺cells in peripheral blood mononuclear cells: Before surgrey 8 mice were randomly selected to detect the percentage of CD133 ⁺/VEGFR2 ⁺ double positive cells in peripheral blood mononuclear cells, serving as the control group. The percentage of CD133⁺/VEGFR2⁺cells in peripheral blood mononuclear cells in the three groups all reached to peak in the first week and wre more higher than the normal control group, UUO group was much higher than Sham group, ATO group was much higher than UUO group, and there were statistical significance(P<0.05). The percentage of CD133⁺/VEGFR2⁺cells in peripheral blood mononuclear cells in the three groups gradually deacreased after 1 week, in Sham group there was no statistical significance comparing to normal control group at 2,3,4 week(P>0.05), UUO group decreased under normal at 2 week and was much lower than normal control group at 3,4 week(P<0.05), ATO group was much higher than normal control group during the whole experiment(P<0.05).â‘¢The degree of tubulointerstitial injury(TI)evaluation: In Sham group the TI evaluation had no apparently changes during the whole experiment, In UUO and ATO groups TI gradually increased along with the surgrey,it was much higher than that in Sham group at the corresponding time period (P<0.05),but ATO group was lower than UUO group at every time of point(P<0.05).â‘£Akt and p-Akt expression: In Sham group the Akt and p-Akt in renal interstitium had no apparently changes during the whole experiment, in UUO group Akt and p-Akt were much more higher than that in Sham group,statistical significanc existed between the two groups at 1 week(P<0.05), then Akt and p-Akt gradually decreased, comparing to Sham group it was significant lower at 3,4 week(P<0.05), in ATO group Akt and p-Akt were reached to peak in the first week, and then gradually deceased along with surgrey, it was higher than Sham and UUO groups at the corresponding time period during the whole group(P<0.05).⑤eNOS expression: In Sham group eNOS in renal interstitium had no apparently changes during the whole experiment, in UUO and ATO groups eNOS gradually decreased along with the sugrey, it was much higher than UUO group at the corresponding time period but still much lower than Sham group at the corresponding time of point at 2,3 and 4 week(P<0.05).â‘¥PTC density evaluation: In Sham group PTC density in renal interstitium had no apparently changes during the whole experiment, in UUO and ATO groups PTC density in renal interstitium gradually decreased along with the sugrey, it was much higher than UUO group at the corresponding time period but still much lower than Sham group at the corresponding time of point at 2,3 and 4 week(P<0.05).The direct linear correlation was found between follows in UUO and ATO groups:p-Akt was positively linear correlated to EPCs(r=0.902, P<0.01); EPCs was positively linear correlated to PTC density(r=0.720, P<0.01); p-Akt was positively linear correlated to eNOS(r=0.569, P<0.01); eNOS was positively linear correlated to PTC density(r=0.762, P<0.01).Conclusion:â‘ Atorvastatin can increase PTC density in UUO mice to postpone renal interstitium fibrosis.â‘¡Atorvastatin may regulate the PI3K/Akt/eNOS signal transduction pathway to increase PTC density in UUO mice.â‘¢Atorvastatin mobilizing EPCs to promote microvascular regeneration and ameliorating EC function to promote endothelial cell repair through regulating PI3K/Akt/eNOS pathway are the two possible mechanisms of increasing PTC density in UUO mice.