Short-Term Preconditioning with Insulin and Glucose Efficiently Protected the Kidney Against Ischemia-Reperfusion Injury via the P-AKT-Bax-Caspase-3 Signaling Pathway in Mice.

Objective: Insulin attaches insulin receptor to activate the PI3-kinase/Akt signaling to maintain glucose homeostasis and inhibit apoptosis. This study determined whether preconditioning with insulin and glucose protects the kidney against ischemia-reperfusion injury (IRI). Methods: Kidney IRI was performed in C57BL/6 mice by clamping the renal vessels for 30 min, followed by reperfusion for 24 h. A total subcutaneous 0.1 unit of insulin along with 10% glucose in drinking water was treated on the mice for 24 h before kidney IRI. The kidney function and injuries were investigated through the determination of BUN and Cr in blood plasma, as well as the apoptosis and the expression of P-AKT, BAX, and caspase-3 in the kidneys. The role of P-AKT in insulin-treated IRI kidneys was tested using an AKT inhibitor. The effects of the preconditional duration of insulin and glucose on IRI kidneys were investigated by expanding the treatment duration to 1, 3, and 6 days. Results: Preconditioning with insulin and glucose protected the kidney against IRI as manifested by a decrease in creatinine and BUN and a reduction of kidney tubular injury. The protection effect was mediated by P-AKT-BAX-caspase-3 signaling pathway resulting in suppression of apoptotic cell death. An AKT inhibitor partially reversed the protective effects of preconditional insulin. The preconditional duration for 1, 3, and 6 days had no differences in improving kidney functions and pathology. Conclusion: A short-term preconditioning with insulin and glucose protected the kidney from IRI through the activation of p-AKT and subsequent reduction of BAX-caspase-3-induced apoptosis. The short-term precondition provides a practicable strategy for protecting the kidney against predictable IRI, such as kidney transplant and major surgical operations with high risk of hypotension.