RESUMEN
The protective effect of an alpha-glucan (designated here as MT-α-glucan) from fruit body of maitake (Grifola frondosa) on NIT-1 pancreatic ß-cells damaged by streptozotocin (STZ) in vitro was investigated. The cell viability, insulin secretion, the activity of superoxide dismutase (SOD), glutathione peroxidase (GSHpx) and the content of reduced glutathione (GSH) increased significantly when the cells were incubated with MT-α-glucan (400, 200 µg ml(-1)). The content of malondialdehyde (MDA), nitric oxide (NO) production, and the activity of NO synthase (NOS), inducible NOS (iNOS) decreased significantly when the cells were incubated with MT-α-glucan. The destructive changes of NIT-1 cells ameliorated when incubated with MT-α-glucan under microscopic observation. These data suggested that MT-α-glucan had obvious protective effect on NIT-1 pancreatic ß-cells damaged by STZ, which might be related to its effects of decreasing levels of ß-cell-destroying factors such as oxidative stress and NO synthesis.
Asunto(s)
Citoprotección/efectos de los fármacos , Glucanos/farmacología , Grifola/química , Células Secretoras de Insulina/citología , Células Secretoras de Insulina/efectos de los fármacos , Estreptozocina/toxicidad , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Cuerpos Fructíferos de los Hongos/química , Glutatión/metabolismo , Glutatión Peroxidasa/metabolismo , Insulina/metabolismo , Secreción de Insulina , Células Secretoras de Insulina/metabolismo , Malondialdehído/metabolismo , Ratones , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa de Tipo II/metabolismo , Estrés Oxidativo/efectos de los fármacos , Superóxido Dismutasa/metabolismoRESUMEN
BACKGROUND: The ability of sesamin from sesame meal to ameliorate insulin resistance in KK-Ay mice (an animal model of type 2 diabetes) was evaluated. RESULTS: Treatment with sesamin (100 or 50 mg kg(-1)) significantly decreased the level of fasting plasma glucose, glycosylated serum protein, serum insulin, triglycerides, cholesterol, free fatty acid and malondialdehyde content of livers. Treatment with sesamin significantly increased the content of hepatic glycogen, reduced glutathione and the activity of superoxide dismutase and glutathione peroxidase. Moreover, the insulin-binding capacity to liver crude plasma membranes increased and histopathological changes of the pancreas were ameliorated in the treatment group. CONCLUSION: Sesamin has hypoglycaemic, hypolipidaemic and the ability to ameliorate insulin resistance in KK-Ay mice, which might be related to its effect on insulin receptors, and thus increases insulin sensitivity.
