Inhibitory effect of leptin on lipopolysaccharide-induced apoptosis of thymocytes

Objective To study the signaling transduction mechanism of leptin, including phosphatidylinositol 3-kinase/AKT （PI3-K/AKT） and cPLA₂ signal pathway. Methods MTT colorimetric assay and Annexin V-FITC/PI double staining for flow cytometry were used to demonstrate the inhibitory effect of leptin on lipopolysaccharide（LPS）-induced toxicity and apoptosis of thymocytes with a cPLA₂ activity kit. RT-PCR was performed to show the suppressive effect of leptin on cPLA₂ activity and cPLA₂ mRNA level in proteins and genes. Effect of a specific inhibitor （LY294002） of PI3-K on apoptosis of thymocytes was detected by flow cytometry. Caspase3 mRNA was determined by RT-PCR. Results Leptin inhibited lipopolysaccharid（eLPS）-induced toxicity and apoptosis of thymocytes, decreased the cPLA₂ activity and cPLA₂ mRNA level in proteins and genes. Conclusion Leptin inhibits toxicity and apoptosis of thymocytes through the PI3-K/AKT and cPLA₂ signal pathway.