Renoprotective effect of calycosin in high fat diet-fed/STZ injected rats: Effect on IL-33/ST2 signaling, oxidative stress and fibrosis suppression

Type 2 diabetes mellitus (T2DM) is a disease with a drastically growing worldwide prevalence. It is usually associated with numerous complications of which; diabetic nephropathy (DN); is a main complication of microvasculature and more seriously, a common cause of end-stage renal disease (ESRD). Unfortunately, both the lack of a definitive remedy alongside the economic and the social burden on DN patients enforces considerable impetus for developing alternative therapies. IL-33 is a newly discovered member of the IL-1 cytokine family. IL33/ST2 signaling plays a crucial role in acute and chronic kidney diseases. Calycosin is an isoflavone with reported IL33 signaling inhibitory activity. The present study aimed to investigate if calycosin possess renal protective effect in high-fat diet/STZ-induced T2DM model and to clarify the potential underlying mechanisms. HFD-STZ control rats showed functional and structural renal damage confirmed by increased serum creatinine, blood urea nitrogen and albuminuria associated with marked renal glomerulosclerosis and interstitial fibrosis. Initiation of inflammation, oxidative stress, and fibrosis was evident as depicted by elevated renal levels of IL33/ST2 mRNA as well as increased renal NF-κBp65, TNF-α, IL-1β, MDA, and TGF-β contents with suppressed Nrf2 and TAC. Calycosin treatment markedly improved the aforementioned makers of renal injury and dysfunction, modulated IL33/ST2 signaling, inflammatory cytokines, oxidative stress and fibrotic processes. This was accompanied by improvement of T2DM-induced renal ultramicroscopic and histopathological alterations.