Role of TBK1 in renal fibrosis in mice with acute kidney injury: relationship with endoplasmic reticulum stress / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the role of TANK-binding kinase-1 (TBK1) in renal fibrosis in mice with acute kidney injury (AKI) and relationship with endoplasmic reticulum stress.Methods:Twenty-four male wild-type C57BL/6 mice, aged 8-10 weeks, weighing 20-25 g, were divided into 4 groups ( n=6 each) using a random number table method: control group (group CON), group AKI, control plus TBK1 inhibitor group (group CON-GSK) and AKI plus TBK1 inhibitor group (group AKI-GSK). In group AKI and group AKI-GSK, folic acid 250 mg/kg was intraperitoneally injected to prepare AKI model.From the first day after folic acid injection, 1% dimethyl sulfoxide 20 ml/kg was intraperitoneally injected every other day in group AKI, and GSK8612 1.5 mg/kg was intraperitoneally injected every other day in group AKI-GSK, 7 times in total.In group CON and group CON-GSK, 1% dimethyl sulfoxide 20 ml/kg and GSK8612 1.5 mg/kg were intraperitoneally injected, respectively, every other day for 7 times in total.On the 14th day after injection of folic acid, the eyeball blood samples were taken to determine the concentrations of serum blood urea nitrogen (BUN) and creatinine (Cr), and the kidney tissues were also extracted, and the pathological results of renal tissue were observed by Sirius red staining, Masson staining and HE staining.The area of renal fibrosis was measured and the tubulointerstitial injury score was calculated.The expression of fibronectin, type I collagen and α-smooth muscle actin was detected by immunofluorescence.The expression of phosphorylated protein kinase R-like endoplasmic reticulum kinase (p-PERK), phosphorylated eukaryotic initiation factor 2α (p-eIF2α), activated transcription factor 4 (ATF4), C/EBP homologous protein (CHOP), phosphorylated inositol-requiring kinase 1α (p-IRE1α), tumor necrosis factor receptor-associated factor 2 (TRAF2), apoptosis-regulating signal kinase 1 (ASK1), caspase-12 and phosphorylated c-Jun N-terminal protein kinase (p-JNK) was detected by Western blot. Results:Compared with group CON, the serum BUN and Cr concentrations, area of renal fibrosis and renal tubulointerstitial injury score were significantly increased, and the expression of fibronectin, type I collagen, α-smooth muscle actin, p-PERK, p-eIF2α, ATF4, CHOP, p-IRE1α, TRAF2, ASK1, caspase-12, and p-JNK was up-regulated in group AKI and group AKI-GSK ( P<0.05), and no significant change was found in the indexes mentioned above in group CON-GSK ( P>0.05). Compared with group AKI, the serum BUN and Cr concentrations, area of renal fibrosis, and tubulointerstitial injury score were significantly decreased, and the expression of fibronectin, type I collagen, α-smooth muscle actin, p-PERK, p-eIF2α, ATF4, CHOP, p-IRE1α, TRAF2, ASK1, caspase-12, and p-JNK was down-regulated in group AKI-GSK ( P<0.05). Conclusions:TBK1 is involved in the process of renal fibrosis in mice with AKI, and the mechanism may be related to the promotion of endoplasmic reticulum stress.