In vivo and in vitro effects of crocetin and its amide derivative on acrylamide-induced neurotoxicity.

Objective: Acrylamide (ACR) is a neurotoxic agent whose damage could be attenuated by antioxidants administration. Crocetin is a saffron-derived antioxidant that has neuroprotective effects. This study evaluates the protective effects of trans-sodium crocetinate (TSC) and its water-soluble derivative, Bis-N-(N-methylpyprazinyl) crocetinate (BMPC) against ACR neurotoxicity. Materials and Methods: PC12 cells were treated with TSC and BMPC (1.95, 3.9, 7.81, 15.62, 31.25, 62.5, 125, 250, 500, and 1000 µM) for 24 hr. ACR was then added at a concentration of 6.5 mM (IC50), and cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide. In the in vivo study, male Wistar rats were treated with ACR (50 mg/kg, intraperitoneal (i.p.)) for 11 days alone or in combination with TSC and BMPC (2.5, 5, and 10 mg/kg, i.p.) or vitamin E (200 IU/kg, i.p.). Motor impairments were then evaluated. The cerebral cortex of sacrificed rats was taken for the malondialdehyde (MDA) and glutathione (GSH) levels measurement. Results: In vitro studies showed that TSC at a concentration of 7.81 µM and BMPC at concentrations of 3.9, 7.81, and 15.62 µM exhibited the lowest toxicity in acrylamide administration. In the in vivo study, pretreatment with 2.5, 5, and 10 mg/kg of TSC ameliorated behavioral impairments, but BMPC could not attenuate them. GSH and MDA were improved by 2.5, 5, and 10 mg/kg TSC and 2.5 mg/kg BMPC. Conclusion: TSC and BMPC administration improved behavioral index and oxidative stress injuries in Wistar rats exposed to ACR through MDA reduction and GSH content enhancement in the cerebral cortex.

Natural compounds regulate the PI3K/Akt/GSK3ß pathway in myocardial ischemia-reperfusion injury.

The PI3K/Akt/GSK3ß pathway is crucial in regulating cardiomyocyte growth and survival. It has been shown that activation of this pathway alleviates the negative impact of ischemia-reperfusion. Glycogen synthase kinase-3 (GSK3ß) induces apoptosis through stimulation of transcription factors, and its phosphorylation has been suggested as a new therapeutic target for myocardial ischemia-reperfusion injury (MIRI). GSK3ß regulatory role is mediated by the reperfusion injury salvage kinase (RISK) pathway, and its inhibition by Akt activation blocks mitochondrial permeability transition pore (mPTP) opening and enhances myocardial survival. The present article discusses the involvement of the PI3K/Akt/GSK3ß pathway in cardioprotective effects of natural products against MIRI.Abbreviations: Akt: protein kinase B; AMPK: AMP-activated protein kinase; ATP: adenosine triphosphate; Bad: bcl2-associated agonist of cell death; Bax: bcl2-associated x protein; Bcl-2: B-cell lymphoma 2; CK-MB: Creatine kinase-MB; CRP: C-reactive-protein; cTnI: cardiac troponin I; EGCG: Epigallocatechin-3-gallate; Enos: endothelial nitric oxide synthase; ER: endoplasmic reticulum; ERK ½: extracellular signal­regulated protein kinase ½; GSK3ß: glycogen synthase kinase-3; GSRd: Ginsenoside Rd; GSH: glutathione; GSSG: glutathione disulfide; HO-1: heme oxygenase-1; HR: hypoxia/reoxygenation; HSYA: Hydroxysafflor Yellow A; ICAM-1: Intercellular Adhesion Molecule 1; IKK-b: IκB kinase; IL: interleukin; IPoC: Ischemic postconditioning; IRI: ischemia-reperfusion injury; JNK: c-Jun N-terminal kinase; Keap1: kelch-like ECH-associated protein- 1; LDH: lactate dehydrogenase; LVEDP: left ventricular end diastolic pressure; LVP: left ventricle pressure; LVSP: left ventricular systolic pressure; MAPK: mitogen-activated protein kinase; MDA: malondialdehyde; MIRI: myocardial ischemia-reperfusion injury; MnSOD: manganese superoxide dismutase; mPTP: mitochondrial permeability transition pore; mtHKII: mitochondria-bound hexokinase II; Nrf-1: nuclear respiratory factor 1; Nrf2: nuclear factor erythroid 2-related factor; NO: nitric oxide; PGC-1α: peroxisome proliferator­activated receptor γ coactivator­1α; PI3K: phosphoinositide 3-kinases; RISK: reperfusion injury salvage kinase; ROS: reactive oxygen species; RSV: Resveratrol; SOD: superoxide dismutase; TFAM: transcription factor A mitochondrial; TNF-α: tumor necrosis factor-alpha; VEGF-B: vascular endothelial growth factor B.