Expression of Toll-like receptors 2/4 and the protective effect of Shenkang injection on renal ischemia-reperfusion injury in diabetic rats

Abstract

Objective To investigate the mechanisms and therapeutic effects of Shenkang injection (SKI) on renal ischemia-reperfusion injury (IRI) in the rats with diabetes mellitus (DM). Methods The DM rat model was induced by high-sugar, high-fat diet plus low-dose intraperitoneal injection of streptozotocin for 6 weeks. Then, the Sparague-Dawley rats were divided into four groups: DM ischemia-reperfusion (DMIR) group, DMIR plus treatment with SKI (DMIR+ SKI) group, DM sham (DMS) group, and normal control sham (NCS) group. The DMIR+ SKI group were treated with SKI (6.0 g/kg/d) for eight weeks after DM model established, while rats of the other groups were treated with normal saline. Afterwards, the renal IRI was induced by a right nephrectomy plus clamping the left renal artery for 45 minutes and reperfusion for 24 hours. Finally, blood drawing and renal tissues collection were made. The serum high mobility group box 1 (HMGB1) was detected with ELISA. The renal expression of HMGB1, Toll-like receptor (TLR) 2, TLR4, myeloid differentiation factor 88 (MyD88), and nuclear factor κBp56 (NF-κBp56) were detected with immunohistochemistry, Western blot, and real-time polymerase chain reaction. Results The level of serum HMGB1 and renal expression of HMGB1, TLR2, TLR4, MyD88, and NF-κBp56 were all significantly higher in DMIR group than in DMS group (P<0.01), but were significantly decreased in the DMIR+ SKI group. Conclusions Our results indicated that TLR2/4 pathway activation might play an important role in renal IRI of DM rats. The renal protective effects of SKI may be related with the TLR2/4 pathway inhibition. Key words: Diabetes mellitus; Ischemia-reperfusion renal injury; Toll-like receptor 2; Toll-like receptor 4; Shenkang injection