ABSTRACT
Oligodendrocytes, the myelinating glial cells of central nervous system, are highly vulnerable to ischemic-induced excitotoxic insult, a phenomenon in which calcium overload triggers cell death. Berberine is an alkaloid extracted from medicinal herbs as Coptidis Rhizoma with several pharmacological effects like inhibition of neuronal apoptosis in cerebral ischemia. We examined the effects of berberine [0.5-4 microM] and glutamate receptors antagonists [MK-801 [10 microM] and NBQX [30 microM] on OLN-93 cell line [a permanent immature rat Oligodendrocyte] during [30, 60, 240 min] oxygen-glucose deprivation [OGD]/24 h reperfusion. The cells were cultured in 12-well plates. The cells were exposed to glucose-free medium and hypoxia in a small anaerobic chamber. Cell viability was evaluated by MTT [3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide] assay. The intracellular calcium levels also were evaluated by Ca[2+]-sensitive indicator Fura-2/AM in presence or absence of berberine [2 microM] during 30 min chemical OGD by NaN3 [20 mM]. Student's t-test and AN OVA were used for statistical analysis. Berberine, MK-801 and NBQX significantly increased Oligodendrocyte viability in all 3 time-scheduled oxygen-glucose deprivation/reperfusion. Berberine at 2 microM produced peak of protection, and increased cell viability to 83%, 77%, and 79% during 30, 60, 240 min ischemic experiments, respectively [P < 0.001]. Berberine significantly attenuated intracellular Ca[2+] rise induced by chemical ischemia, and this effect of berberine was significantly stronger than MK-801 and NBQX [P < 0.001]. We concluded that berberine protected OLN-93 Oligodendrocyte against ischemic induced excitotoxic injury. Attenuation of intracellular Ca[2+] overload by berberine may be the key mechanism that saved OLN-93 from excitotoxicity damage
ABSTRACT
Alzheimer's disease [AD] is characterized by progressive neuronal loss in hippocamp. Epidermal neural crest stem cells [EPI-NCSC] can differentiate into neurons, astrocytes and oligodendrocytes. The purpose of this study was to evaluate the effects of transplanting EPI-NCSC into AD rat model. Two weeks after induction of AD by injection of Amyloid-beta 1-40 into CA1 area of rat hippocamp, Y-maze and single-trial passive avoidance tests were used to show deficit of learning and memory abilities. EPI-NCSC were obtained from the vibrissa hair follicle of rat, cultured and labeled with bromodeoxyuridine. When Alzheimer was proved by behavioral tests, EPI-NCSC was transplanted into CA3 area of hippocamp in AD rat model. The staining of EPI-NCSC markers [nestin and SOX10] was done in vitro. Double-labeling immunofluorescence was performed to study survival and differentiation of the grafted cells. We showed that transplanted EPI-NCSC survive and produce many neurons and a few glial cells, presenting glial fibrillary acidic protein. Total number of granule cells in hippocamp was estimated to be more in the AD rat model with transplanted cells as compared to AD control group. We observed that rats with hippocampal damage made more errors than control rats on the Y-maze, when reward locations were reversed. Transplanted cells were migrated to all areas of hippocamp and the total number of granule cell in treatment group was equal compared to control group. Transplantation of EPI-NCSC into hippocamp might differentiate into cholinergic neurons and could cure impairment of memory in AD rat model