Chronic Treatment with Curcumin Prevents Vascular Dysfunction in the Aorta of Type 1 Diabetes by Restoring Ca2+ Mishandling and Modulating HSP70 Levels

Vascular Smooth Muscle Cells (VSMC) dysfunction is a major contributor to Type 1 diabetes (T1D)-associated vascular complications. Ca²⁺ is a key messenger responsible for maintaining VSMC tone and function, and alterations in its cytosolic levels are central to diabetes-related vasculopathy. Heat Shock Protein 70 (HSP70), a multifaceted chaperone present intracellularly (iHSP70), regulates vascular reactivity by supporting Ca²⁺ handling, and extracellularly (eHSP70) activates immune signaling. Disruption of eHSP70/iHSP70 balance has been implicated in T1D-associated VSMC dysfunction. Curcumin, a phytochemical found in turmeric, is an emerging therapeutic adjuvant for treating a wide range of pathologies, including diabetes. However, whether curcumin modulates Ca²⁺ dynamics and HSP70 expression, thereby improving VSMC function, in diabetic aorta remains unclear. To investigate this, Streptozotocin-induced diabetic rats (i.p. 65 mg/kg) were treated with curcumin (300 mg/kg) for 28 days. Vascular function was evaluated using wire myography to assess changes in biphasic contraction curve and Ca²⁺ dynamics, while HSP70 was quantified using Western blotting and ELISA. Structural alterations were analyzed by assessing collagen and elastin using Picrosirius staining and fluorescence microscopy. Chronic curcumin treatment improved vascular function by normalizing Ca²⁺ mishandling, restoring the eHSP70/iHSP70 ratio, reducing hypercontractility, and mitigating arterial structural alterations. These findings indicate that curcumin could potentially ameliorate diabetes-related VSMC dysfunction by restoring Ca²⁺ homeostasis and modulating HSP70.