Medicinal Plants Support the Amylin-suppressed Viability of Islet Β- Cells

The proliferation of β-cells is a main contributor to the cell mass maintenance in the pancreatic islets. In our earlier work the suppression of β-cell growth by aggregated peptide hormone of pancreas, amylin, has been proved. The in vitro protection of the cells from aggregated amylin-associated death by several plant extracts and their constituents has been shown. In the present work the development of β-cells was suppressed preliminary by aggregated amylin. Then, the ethanol extracts of rose petals (Rosa damascena), melilot (Melilotus officinalis), leaves of grape (Vitis vinifera) and sorrel (Rumex Confertus) and the phenol glycoside fraction of rose petals were added to the cultivation medium, and the growth of cells suppressed by aggregate amylin was observed. The promotion of cells viability was registered with trypan blue exclusion test and the DNA-comet analysis. In the other series of experiments, the reverse of pre-formed amylin aggregates in the presence of several plant preparations was registered using Thioflavin T fluorescence. The significant linear correlation (r = 0.75, p=0.02) between two propensities of plant: to inhibit amylin aggregation (observed in our previous work) and to dissociate the peptide aggregates was observed. Probably, both of these properties of plant preparations are conditioned by their specific interaction with amylin molecule and elucidate the perspective of studied plants in protection of pancreatic islet β-cells against amylin-induced lost. INTRODUCTION: Pancreatic islets consist of 6080% beta cells, which secrete insulin, a hormone of profound importance in the regulation of carbohydrate, fat and protein metabolism. Beta cells death and/or dysfunction result in an insufficient amount of insulin that leads to high glucose levels in the blood, a metabolic disorder known as Diabetes mellitus (DM). The increase in beta cell mass can take place either through an increase in the cell number by neogenesis and proliferation (hyperplasia), or through an increase in the cell volume (hypertrophy) 1 . QUICK RESPONSE CODE DOI: 10.13040/IJPSR.0975-8232.IJP.2(9).448-53 Article can be accessed online on: www.ijpjournal.com DOI link: http://dx.doi.org/10.13040/IJPSR.0975-8232.IJP.2(9).448-53 The primary mechanism of beta cell mass expansion in the postnatal period is replication 2, 3, 4 . An important source of new pancreatic beta cells in adult mice is shown being the proliferation of preexisting cells 2, 5, 6 . Many studies aiming to establish new therapeutic applications for DM are targeted at understanding and regulating the beta cells replication as a very important contributor to the increase of adult beta cell mass 7 . It is crucial to find the factors maintaining the cell proliferation. This knowledge could lead to the development of new methods to increase the cell mass in DM. Amylin is a secretory product of pancreatic β-cells 8, 9 . It is a regulatory peptide functioning in the islet β-cells and participating in regulation of glucose metabolism along with insulin. Amyloid deposits of amylin were found in the islets of β-cells in DM in humans and some mammals. Their cytotoxicity