Role of CXCR6-mediated activation of natural killer T cells in renal fibrosis following acute kidney injury in mice / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the role of CXC chemokine receptor 6 (CXCR6)-mediated activation of natural killer T (NKT) cells in renal fibrosis following acute kidney injury (AKI) in mice.Methods:Eighteen male wild-type C57BL/6 mice and 18 CXCR6 knockout C57BL/6 mice, aged 8-10 weeks, weighing 20-30 g, were divided into 6 groups ( n=6 each) using a random number table method: wild-type mouse control group (group WT-CON), CXCR6 knockout mouse control group (group CXCR6 -/--CON), wild-type mouse with AKI group (group WT-AKI), CXCR6 knockout mouse with AKI group (group CXCR6 -/--AKI), wild-type mouse with AKI + NKT cell adoptive transfer group (group WT-AKI-NKT) and CXCR6 knockout mouse with AKI + NKT cell adoptive transfer group (group CXCR6 -/--AKI-NKT). Folic acid 250 mg/kg was intraperitoneally injected to establish the model of renal fibrosis in mice with AKI.NKT cellsuspension 250 μl(1×10 6 cells) was injected through the tail vein on the 4th and 9th days after folic acid injection in group WT-AKI-NKT and group CXCR6 -/--AKI-NKT, respectively.Blood samples were taken from orbital at day 14 after folic acid injection for determination of the concentrations of serum blood urea nitrogen (BUN) and creatinine (Cr). The animals were sacrificed, and renal tissues were obtained for observation of the area of renal fibrosis (by Sirius red staining) and renal injury (using H&E staining) which was scored and for determination of the proportion of CD1d Tetramer+ cells (by flow cytometry), the number of CD206 and α-smooth muscle actin (α-SMA) double positive (CD206 + -α-SMA + ) cells (by immunofluorescence) and expression of interleukin (IL)-4 and IL-13 mRNA (by real-time polymerase chain reaction). Results:Compared with group WT-CON, the BUN and Cr levels, renal injury scores, area of renal fibrosis, proportion of CD1d Tetramer + cells and CD206 + -α-SMA + cell count were significantly increased, and the expression of IL-4 and IL-13 mRNA was up-regulated in group WT-AKI and WT-AKI-NKT ( P<0.05). Compared with group WT-AKI, the BUN and Cr levels, renal injury scores, area of renal fibrosis, proportion of CD1d Tetramer + cells and CD206 + -α-SMA + cell count were significantly increased, and the expression of IL-4 and IL-13 mRNA was up-regulated in group WT-AKI-NKT ( P<0.05), and the BUN and Cr levels, renal injury scores, area of renal fibrosis, proportion of CD1d Tetramer + cells and CD206 + -α-SMA + cell count were significantly decreased, and the expression of IL-4 and IL-13 mRNA was down-regulated in group CXCR6 -/--AKI ( P<0.05). Compared with group CXCR6 -/--CON, the BUN and Cr levels, renal injury scores, area of renal fibrosis, proportion of CD1d Tetramer + cells and CD206 + -α-SMA + cell count were significantly increased in group CXCR6 -/--AKI and group CXCR6 -/--AKI-NKT ( P<0.05). Compared with group CXCR6 -/--AKI, the BUN and Cr levels, renal injury scores, area of renal fibrosis, proportion of CD1d Tetramer + cells and CD206 + -α-SMA + cell count were significantly increased, and the expression of IL-4 and IL-13 mRNA was up-regulated in group CXCR6 -/--AKI-NKT ( P<0.05). Conclusion:CXCR6-mediated activation of NKT cells is involved in renal fibrosis following AKI in mice, and the mechanism may be related to promoting Th2 cytokine-mediated M2 macrophage-myofibroblast transformation.