Protective Effect of Nicotinamide on Neuronal Cells under Oxygen and Glucose Deprivation and Hypoxia/Reoxygenation

Abstract

Nicotinamide (vitamin B₃) reduces the infarct volume following focal cerebral ischemia in rats; however, its mechanism of action has not been reported. After cerebral ischemia and/or reperfusion, reactive oxygen species (ROS) and reactive nitrogen species may be generated by inflammatory cells through several cellular pathways, which can lead to intracellular calcium influx and cell damage. Therefore, we investigated the mechanisms of action of nicotinamide in neuroprotection under conditions of hypoxia/reoxygenation. Results showed that nicotinamide significantly protected rat primary cortical cells from hypoxia by reducing lactate dehydrogenase release with 1 h of oxygen-glucose deprivation (OGD) stress. ROS production and calcium influx in neuronal cells during OGD were dose-dependently diminished by up to 10 mM nicotinamide (p < 0.01). This effect was further examined with OGD/reoxygenation (H/R). Cells were stained with the fluorescent dye 4,6-diamidino-2-phenylindole (DAPI) or antibodies against anti-microtubule-associated protein-2 and cleaved caspase-3. Apoptotic cells were studied using Western blotting of cytochrome c and cleaved caspase-3. Results showed that vitamin B₃ reduced cell injury, caspase-3 cleavage and nuclear condensation (DAPI staining) in neuronal cells under H/R. In addition, nicotinamide diminished c-fos and zif268 immediate-early gene expressions following OGD. Taken together, these results indicate that the neuroprotective effect of nicotinamide might occur through these mechanisms in this in vitro ischemia/reperfusion model.

Nicotinamide Reverses Neurological and Neurovascular Deficits in Streptozotocin Diabetic Rats

“…High glucose-induced accumulation of poly(ADP-ribosyl)ated proteins and HNE adducts in HSC was alleviated by nicotinamide, which is consistent with reports of its neuroprotective effect in neural cell lines exposed to high glucose concentrations or hypoxia/reoxygenation (Shen et al, 2004;Obrosova et al, 2005a). In rat primary cortical neurons, nicotinamide reduced lactate dehydrogenase release, ROS production, calcium influx, caspase-3 activation, and cell injury after oxygen-glucose deprivation and reoxygenation (Shen et al, 2004).…”

“…This temporal change in thermal sensitivity parallels the pattern of sensory change that has been observed in subjects with diabetes, albeit over a much longer time course (Dyck et al, 2000). This transient thermal hyperalgesia has been postulated to reflect alterations in neuropeptide metabolism (Calcutt et al, 2004) and/or neuronal calcium signaling (Li et al, 2005a), which would provide a mechanistic explanation for the salutary effects of nicotinamide (Shen et al, 2004). The subsequent development of thermal hypoalgesia may reflect impairment of C fiber function secondary to impaired neurotrophic support.…”

“…PARP activation leads to the depletion of its substrate NAD ϩ , energy failure, inhibition of glyceraldehyde 3-phosphate dehydrogenase of glycolysis, altered gene transcription, and, in extreme cases, cell necrosis (Garcia Soriano et al, 2001;Southan and Szabo, 2003;Obrosova et al, 2004Obrosova et al, , 2005a. PARP inhibition seemed neuroprotective in pathological conditions associated with oxidative stress (Maiese and Chong, 2003;Shen et al, 2004). In animal models of DPN, PARP pharmacological inhibition (Maiese and Chong, 2003;Obrosova et al, 2004Obrosova et al, , 2005a or gene deficiency reversed or protected from motor and sensory nerve conduction velocity (NCV) slowing, as well as thermal and mechanical hyperalgesia.…”

“…It has been shown to improve energy status in ischemic tissues (Yang et al, 2002), exhibit antioxidant properties (Melo et al, 2000;Shen et al, 2004), regulate neuronal calcium fluxes (Shen et al, 2004), and inhibit apoptosis (Maiese and Chong, 2003;Shen et al, 2004), making it an attractive potential agent for the treatment of DPN. Moreover, nicotinamide has been used in human clinical trials with a low incidence of side effects or toxicity (Gale et al, 2004).…”

Cell Life Versus Cell Longevity: The Mysteries Surrounding the NAD+ Precursor Nicotinamide

“…Nicotinamide offers significant protection for neurons and can provide protection against free radical injury [13], anoxia [75], and oxygen-glucose deprivation [29,137]. In cortical neurons, nicotinamide antagonizes cell injury during free radical generating toxins such as tertiary butylhydroperoxide [76].…”