Abstract
Studies have reported attenuation of insulin resistance (IR) by improving phosphorylation of the insulin signalling pathway. However, the upstream molecular signalling pathway is still elusive. In this study, Western blot was used to evaluate the phosphorylation level of the insulin signalling pathway and the AMPK pathway. 2-NBDG was used to evaluate glucose uptake. Ca2+ imaging was used to assess change of intracellular Ca2+ concentration. We found that NaHS enhanced the intracellular Ca2+ concentration and glucose uptake and activated the insulin signalling cascade in a palmitic acid (PA)-induced IR model in C2C12 cells. Furthermore, activation of the IRS1/PI3K/AKT pathway and glucose uptake were decreased when AMPK or CaMKKβ was inhibited. Our study also showed that the mitochondrial electron transport chain, ATP production, and intramitochondrial cAMP declined in the IR model but that this effect was reversed by NaHS, an effect that may be mediated by the Ca2+/CaMKK2/AMPK and PI3K/AKT pathways. Our data indicate that H2S improves activation of the insulin signalling cascade and glucose uptake via activation of the Ca2+/CaMKK2/AMPK pathway and mitochondrial metabolism in C2C12 cells. Furthermore, NaHS protects mitochondrial function and maintains normal ATP production by activating the cAMP system and the Ca2+/CaMKK2/AMPK and PI3K/ATK pathways.