Saponins of Momordica charantia increase insulin secretion in INS-1 pancreatic ß-cells via the PI3K/Akt/FoxO1 signaling pathway.

Saponins are the main bioactive substances with anti-hyperglycemic activities of Momordica charantia. This study aimed to verify the effects of M. charantia saponins on insulin secretion and explore the potential underlying mechanisms in INS-1 pancreatic ß-cells. We injured INS-1 cells with 33.3mM glucose and then treated them with saponins. Saponins improved cell morphology and viability as demonstrated by inverted microscopy and CCK8 detection and significantly increased insulin secretion in a concentration-dependent manner as shown by ELISA. Thus, we obtained the optimal concentration for the subsequent experiments. Potential mechanisms were explored by immunofluorescence, western blotting, and RT-qPCR techniques. First, saponins increased the mRNA and protein levels of IRS-2 but decreased the serine 731 phosphorylation level of IRS-2. Moreover, saponins increased the phosphorylation of Akt protein and decreased the protein level of FoxO1, which were both reversed by the PI3K inhibitor ly294002. Furthermore, saponins increased the protein level of the downstream molecule and insulin initiating factor PDX-1, which was also reversed by ly294002. Saponins also increased Akt and PDX-1 mRNA and decreased FoxO1 mRNA, which were both reversed by ly294002. Saponins increased glucose-stimulated insulin secretion (GSIS) and intracellular insulin content, which were reversed by ly294002, as determined by ELISA. The immunofluorescence results also confirmed this tendency. In conclusion, our findings improve our understanding of the function of saponins in INS-1 pancreatic ß-cells and suggest that saponins may increase insulin secretion via the PI3K/Akt/FoxO1 signaling pathway.

Saponins of Momordica charantia increase insulin secretion in INS-1 pancreatic ß-cells via the PI3K/Akt/FoxO1 signaling pathway.

Saponins are the main bioactive substances with anti-hyperglycemic activities of Momordica charantia. This study aimed to verify the effects of M. charantia saponins on insulin secretion and explore the potential underlying mechanisms in INS-1 pancreatic ß-cells. We injured INS-1 cells with 33.3mM glucose and then treated them with saponins. Saponins improved cell morphology and viability as demonstrated by inverted microscopy and CCK8 detection and significantly increased insulin secretion in a concentration-dependent manner as shown by ELISA. Thus, we obtained the optimal concentration for the subsequent experiments. Potential mechanisms were explored by immunofluorescence, western blotting, and RT-qPCR techniques. First, saponins increased the mRNA and protein levels of IRS-2 but decreased the serine 731 phosphorylation level of IRS-2. Moreover, saponins increased the phosphorylation of Akt protein and decreased the protein level of FoxO1, which were both reversed by the PI3K inhibitor ly294002. Furthermore, saponins increased the protein level of the downstream molecule and insulin initiating factor PDX-1, which was also reversed by ly294002. Saponins also increased Akt and PDX-1 mRNA and decreased FoxO1 mRNA, which were both reversed by ly294002. Saponins increased glucose-stimulated insulin secretion (GSIS) and intracellular insulin content, which were reversed by ly294002, as determined by ELISA. The immunofluorescence results also confirmed this tendency. In conclusion, our findings improve our understanding of the function of saponins in INS-1 pancreatic ß-cells and suggest that saponins may increase insulin secretion via the PI3K/Akt/FoxO1 signaling pathway.

Insulinoma canino: relato de caso / Canine insulinoma: case reports

O insulinoma é um tumor das células ß do pâncreas, que têm a função de produzir e secretar insulina e, geralmente são malignos em cães. O presente trabalho descreve o diagnóstico e o manejo terapêutico de três casos de insulinoma. Os sinais clínicos dos animais relatados variaram de acordo com a severidade e a duração da hipoglicemia. O diagnóstico presuntivo se deu através dos sinais clínicos e da dosagem de insulina sérica no momento de mais intensa hipoglicemia e, o diagnóstico definitivo foi obtido por meio de exame histopatológico nos três casos relatados. O tratamento realizado variou de acordo com a intensidade dos sinais clínicos.(AU)

Insulinoma is a tumor of the ß cells of the pancreas, which have the function to produce and secrete insulin and are usually malignant in dogs. This paper describes the diagnosis and therapeutic management of three cases of insulinoma. The clinical signs reported animals varied according to the severity and duration of hypoglycemia. The presumptive diagnosis was based on clinical signs and serum insulin dosage at the time of hypoglycemia and more intense, the definitive diagnosis was made by histopathological examination in three of the reported cases. The treatment was varied according to the severity of clinical signs.(AU)

Gestational diabetes induces pancreatic beta-bells apoptosis in adult rat offspring / Diabetes gestacional induce apoptosis de células beta del páncreas en crías de ratas adultas

Several studies indicated that pancreatic ß-cell death occurs in both type 1 and type 2 diabetes. This experimental study was designed to determine the effect of gestational diabetes on the ß-cells in 16-week-old rat offspring. By this aim, adult Wistar rats aged 10-12 weeks were randomly allocated in control and diabetic groups. The diabetic group received 40 mg/kg/body weight of streptozotocin (STZ) on day zero of gestation. After delivery, diabetic offspring of GDM mothers and controls at the age of 16 weeks were sacrificed and pancreases harvested and fixed. The number of ß-cells and were counted by Gomori's method staining. Also, apoptosis in pancreas tissue of diabetic and control offspring was detected by TUNEL assay. Results showed a significant reduction in ß-cell number in offspring of GDM (p<0.05). TUNEL assay showed that the number of apoptotic cells increased in GDM compared to controls (P<0.05). This study revealed that gestational diabetes induces pancreatic beta-cells apoptosis in 16-week-old rat offspring.

Varios estudios indican que la muerte de las células ß del páncreas se produce tanto en la diabetes Tipo 1 como en la Tipo 2. Este estudio experimental fue diseñado para determinar el efecto de la diabetes gestacional en las células ß del páncreas en crías de ratas de 16 semanas. Para ello, ratas Wistar adultas de entre 10-12 semanas fueron asignadas al azar en dos grupos: control y diabetes. El grupo diabetes recibió 40 mg / kg / peso corporal de estreptozotocina (STZ) en el día cero de la gestación. Después del parto, a las 16 semanas, las crías de las madres diabéticas y controles de madres con diabetes gestacional (MDG), fueron sacrificadas para la extracción del páncreas, el cual posteriormente fue fijado. Se contó el número de células ß del páncreas mediante tinción con el método de Gomori. Además, se detectó apoptosis en el tejido del páncreas de la descendencia diabética y el grupo control mediante un ensayo TUNEL. Los resultados mostraron una reducción significativa en el número de células b en la descendencia de MDG (p <0,05). El ensayo TUNEL mostró que el número de células apoptóticas aumentó en MDG en comparación con los controles (P <0,05). Este estudio reveló que la diabetes gestacional induce apoptosis de células ß en el páncreas de crías de ratas de 16 semanas.