Interleukin-17A is closely correlated with the progression of renal epithelial-mesenchymal transition in spontaneously hypertensive rats

Abstract

To explore the role of interleukin-17A (IL-17A) in renal epithelial- mesenchymal transition (EMT) in essential hypertensive nephropathy. Four-week-old spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats (control group) were both randomized into 4 groups (n=5) for observation at 4, 6, 10 and 30 weeks of age. Blood pressure of the rats was monitored using a noninvasive tail artery blood pressure measurement instrument. The percentage of Th17 cells in the splenocytes was analyzed using flow cytometry. The mRNA and protein expression levels of IL-17A, iNOS, Arg-1, E-cadherin, and α-SMA in the kidneys of the rats were detected using RT-PCR and immunohistochemical staining, respectively, and plasma levels of IL-17A were regularly detected using ELISA. At the age of 6 weeks, the SHRs began to show significantly higher blood pressure with greater Th17 cell percentage in the splenocytes and high renal expression and plasma level of IL-17A than WKY rats (P < 0.05 or P < 0.01). At 30 weeks, renal expression of E-cadherin mRNA and protein was significantly lower and the expression of Arg-1 mRNA and protein was significantly higher in SHR than in WKY rats (P < 0.01). Compared with the WKY rats, the SHRs showed significantly higher mRNA and protein expressions of iNOS at 6 and 10 weeks (P < 0.05 or 0.01) and higher α-SMA mRNA and protein expressions since 10 weeks of age (P < 0.05 or 0.01). In SHRs older than 10 weeks, renal IL-17A mRNA and protein expression levels were negatively correlated with those of E-cadherin (r=-0.731, P < 0.05; r=-0.827, P < 0.01) and positively correlated with those of α-SMA (r=0.658, P < 0.05; r=0.968, P < 0.01). IL-17A is closely correlated with the progression of renal EMT in SHR and plays its role possibly by mediating M1/M2 polarization of renal infiltrating macrophages.