Agomelatine Mitigates Kidney Damage in Obese Insulin-Resistant Rats by Inhibiting Inflammation and Necroptosis via the TNF-α/NF-ĸB/p-RIPK3 Pathway

Obesity is a risk factor for chronic kidney disease. The expansion of adipose tissues in obesity induces insulin resistance and low-grade systemic inflammation, promoting kidney damage. Our previous studies have demonstrated that agomelatine (AGOM) exerts renoprotective effects in experimental models of obesity and insulin resistance through various mechanisms, including the attenuation of ER stress and oxidative stress. This study aimed to further explore the effects of agomelatine on renal inflammation, insulin signaling, and necroptosis in obese, insulin-resistant rats. Obesity was induced in rats with a high-fat diet for 16 weeks, followed by 4 weeks of treatment with 20 mg kg^-1 day^-1 of AGOM or 10 mg kg^-1 day^-1 of pioglitazone (PIO). The results showed that insulin resistance was improved after treatment with AGOM and PIO, as demonstrated by the reduction in fasting plasma glucose, insulin, and HOMA-IR. Both treatments restored the levels of renal insulin signaling proteins. Moreover, AGOM inhibited TNFα, TNFR1, NF-ĸB, COX2, and IL1β, which attenuated the necroptosis-related proteins RIPK3 and MLKL. AGOM also prevented kidney DNA fragmentation, as detected by the TUNEL assay. In an obese condition, the level of the tight junction protein claudin-1 (CLDN1) was enhanced after being treated with AGOM. In conclusion, the novel mechanisms associated with AGOM and involved in limiting kidney injury were the inhibition of the TNFα/NF-ĸB/p-RIPK3 pathway and a reduction in inflammation and necroptosis. This suggested that AGOM could be an effective treatment for inhibiting kidney dysfunction in cases of obesity and insulin resistance. These findings open new avenues for the management of renal dysfunction, with implications for personalized medicine.