Neurotherapeutic Efficacy of Nano-curcumin or Nano-chromium Against Streptozotocin-induced Diabetic Neuropathy via Modulation of Oxidative Stress, Pyroptosis, Tau Deposition, miR-223-3p and miR-124

This study aimed to investigate how nano curcumin (Nano-Cur) or nano-chromium chloride (Nano-CrCl) in comparison with metformin (Met), can reduce diabetic neuropathy caused by streptozotocin (STZ) in rats. Seventy Wistar albino male rats were randomly divided into seven groups (ten rats/group): control; STZ-induced diabetes; diabetic rats receiving daily oral doses of Nano-Cur, Cur, Nano-CrCl, CrCl, and Met. The present results show that all treated groups significantly alleviated diabetic neuropathy by restoring serum insulin and glucose levels, enhancing cerebral antioxidant activities and activating IR/PI3K/AKT, normalizing neurotransmitters, decreasing oxidative stress markers (MDA), and reducing inflammatory biomarkers and pyroptotic biomarkers. At the molecular level, the levels of GSK3B, JAK-2, STAT-3, AMPK, and BACE1 were significantly downregulated in all treated diabetic groups compared to the diabetic group, especially Nano-Cur and Met. However, Cur, Nano-CrCl, and CrCl did not cause any significant (p > 0.05) alteration in ACh levels compared to the diabetic group. Additionally, the Nano-Cur, Cur, and Met groups exhibited a marked increase in miRNA-223-3p and miRNA-124 levels, whereas Nano-CrCl and CrCl showed no significant changes in these miRNAs when compared to the diabetic group.