Nano-Curcumin Protects Against Sodium Nitrite-Induced Lung Hypoxia Through Modulation Of Mitogen-Activated Protein Kinases/C-Jun Nh2-Terminal Kinase Signaling Pathway

Background and objective This study was designed to compare the efficacy of curcumin (CRN) with that of nano-curcumin (N-CRN) in the mitigation of various biochemical indices in hypoxic lung induced by sodium nitrite (SN) in rats. Methods Twenty-four adult male albino rats were divided into 4 groups. Group 1: control group received carboxy methyl cellulose; Group 2: hypoxic group injected with single dose of SN (60 mg/kg, s.c.); Group 3: SN-intoxicated rats pre-injected with CRN (100 mg/kg, i.p.); and Group 4: SN-intoxicated rats pre-injected with N-CRN (100 mg/kg, i.p.). Curcumin and N-CRN were administered intraperitoneally 2 hour prior to SN intoxication. Hemoglobin concentration, serum tumor necrosis factor-alpha (TNF-alpha), and caspase-3 were analyzed. Gene expression of hypoxia inducible factor-1 (HIF-1 alpha), matrix metallo-proteinases (MMP)-2, and tissue inhibitors of metalloproteinases (TIMPs)-2, as well as the protein expression of mitogen-activated protein kinases (MAPKs) and c-Jun NH2-terminal kinase (JNK) were examined in lung tissues. Results Hemoglobin level was markedly reduced, and serum TNF-alpha and caspase-3 were significantly elevated post SN intoxication. The lung MMP-2 and HIF-1 alpha mRNA were overexpressed in the hypoxic group; while TIMP-2 mRNA was downregulated. Sodium nitrite administration increased proteins' expressions of MAPK and JNK. Pretreatment with CRN or N-CRN markedly mitigated those alterations. These results were supported by histopathological examinations of lung tissue. Conclusion Interestingly, N-CRN exhibited a pronounced protective effect via suppression of inflammatory and apoptotic biomarkers and modulation of MAPK/JNK signaling pathway.