Relationship between CXCL16 and natural killer T cells during renal fibrosis in mice with acute kidney injury / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the relationship between chemokine CXC-ligand 16 (CXCL16) and natural killer T cells during renal fibrosis in mice with acute kidney injury (AKI).Methods:Twenty-four healthy male C57BL/6 mice, aged 8-10 weeks, weighing 20-30 g, were divided into 4 groups ( n=6 each) using a random number table method: control group (group C), AKI group, control+ rCXCL16 group (group C-rCXCL16) and AKI+ rCXCL16 group.In AKI-rCXCL16 and AKI groups, folic acid 250 mg/kg was intraperitoneally injected to induce AKI in anesthetized mice, and rCXCL16 0.1 mg/kg and the equal volume of solution were intraperitoneally injected, respectively, at 3, 6, 9 and 12 days after injection of folic acid.The equal volume of solution and rCXCL16 were intraperitoneally injected at the corresponding time points in group C and group C-rCXCL16, respectively.The orbital blood samples were taken on day 14 after injection of folic acid for determination of the serum blood urea nitrogen (BUN) and creatinine (Cr) concentrations.The renal tissues were obtained for measurement of the renal fibrosis size (using Sirius red staining and Masson staining), for determination of the expression of fibronectin (FN), collagen-Ⅲ (Col-Ⅲ) and α-smooth muscle actin (α-SMA) (by immunofluorescence) and expression of interleukin-4 (IL-4), mannose receptor (CD206) and arginase 1 (Arg-1) mRNA (by real-time polymerase chain reaction), and for evaluation of the ratio of CD1d Tetramer + -IL-4 + cells (by flow cytometry). Results:Compared with group C, the serum BUN and Cr concentrations were significantly increased, the renal fibrosis size was increased, the expression of IL-4, CD206, Arg-1 mRNA, FN, Col-Ⅲ and α-SMA was up-regulated, and the ratio of CD1d Tetramer + -IL-4 + cells was increased in AKI and AKI-rCXCL16 groups ( P<0.05), and no significant change was found in the parameters mentioned above in group C-rCXCL16 ( P>0.05). Compared with group AKI, the serum BUN and Cr concentrations were significantly increased, the renal fibrosis size was increased, the expression of IL-4, CD206, Arg-1 mRNA, FN, Col-Ⅲ and α-SMA was up-regulated, and the ratio of CD1d Tetramer + -IL-4 + cells was increased in group AKI-rCXCL16 ( P<0.05). Conclusion:The mechanism by which CXCL16 is involved in the process of renal fibrosis is related to the recruitment of natural killer T cells secreting IL-4 which regulates macrophage M2 polarization in mice with AKI.