[Experimental study on the mechanism of glycogen synthase kinase-3β inhibitor on acute kidney injury of acute necrotizing pancreatitis in rats].

OBJECTIVE: To explore the protective mechanism of glycogen synthase kinase-3β (GSK-3β) inhibitor TDZD-8 on acute necrotizing pancreatitis (ANP) associated kidney injury in rats.

METHODS: SPF male Wistar rats were randomly divided into four groups (n = 20): sham operation group (Sham group), ANP model group, TDZD-8 intervention group and TDZD-8 control group. The rat ANP model was prepared by retrograde injection of 5% sodium taurocholate into the bile duct; the same volume of normal saline was injected into the pancreatic duct of the Sham group. The TDZD-8 intervention group and the TDZD-8 control group were injected with GSK-3β inhibitor TDZD-8 (1 mL/kg) via the femoral vein 30 minutes before the model or sham operation; the ANP model group and the Sham group were injected equal volume of 10% dimethyl sulfoxide (DMSO). Rats in each group were sacrificed at 12 hours after operation to measure the serum amylase (AMY), blood lipase (LIPA), serum creatinine (SCr) and blood urea nitrogen (BUN) levels and to observe the pathological changes of pancreatic tissues and kidney tissues. Ultrastructural change of renal cells was analyzed by transmission electron microscopy. Serum interleukin-1β (IL-1β) and interleukin-6 (IL-6) levels were evaluated by enzyme linked immunosorbent assay (ELISA). The activation of nuclear factor-ΚBp65 (NF-ΚBp65) was evaluated by immunohistochemistry assay. The protein expressions of GSK-3β, phospho-GSK-3β (Ser 9), tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), intercellular adhesion molecule-1 (ICAM-1) and interleukin-10 (IL-10) in the kidney were determined by Western Blot.

RESULTS: Compared with the Sham group, the serum and inflammatory factors levels of the ANP model group were significantly increased, the pathological damage of the pancreas and kidney tissues were severe, the histopathological score was significantly increased, the expression of NF-ΚBp65 was enhanced in the nucleus of the kidney tissue, and the expressions of GSK-3β, TNF-α, ICAM-1 and iNOS were significantly enhanced, and the expressions of p-GSK-3β(Ser 9) and IL-10 were significantly attenuated. Compared with the ANP model group, TDZD-8 pretreatment significantly reduced serum and inflammatory factor levels in the ANP model group [AMY (kU/L): 5.60±0.30 vs. 10.07±0.34, LIPA (U/L): 1 111.0±110.8 vs. 2 375.0±51.1, SCr (μmol/L): 47.38±1.48 vs. 72.50±2.43, BUN (mmol/L): 17.6±1.0 vs. 26.0±1.0, IL-1β (ng/L): 195.90±5.50 vs. 332.40±38.29, IL-6 (ng/L): 246.10±26.74 vs. 385.30±32.19, all P < 0.01]; pathological damage of pancreas and kidney tissue (histopathological score: 7.1±0.4 vs. 12.1±0.3, 301.2±7.5 vs. 433.5±13.8, both P < 0.01) and ultrastructural damage of renal cells were alleviated; the expression of NF-ΚBp65 in the nucleus was significantly decreased; the expression of p-GSK-3β (Ser 9) was significantly increased, and blocking GSK-3β activity could inhibit the expressions of TNF-α, ICAM-1, iNOS and increase the expression of IL-10, while the expression of GSK-3β in renal tissues was not statistically significant. There were no significant differences between the TDZD-8 control group and the Sham group.

CONCLUSIONS: Blockade of GSK-3β activity by TDZD-8 exerts the protective effect against kidney injury by inhibiting the inflammation signaling pathway in ANP. It can alleviate histopathological and ultrastructural changes in kidney injury, which protection mechanism is mediated by NF-ΚB and its related inflammatory mediators.