J Biomed Res.  2013 Mar;14(1):28-34.

Anti-diabetic effect of acid hydrolyzed silk peptides via cytoprotection of pancreas beta-cells and up-regulation of glucose uptake in muscle cells

• Joo SS

Abstract

In this study, we observed anti-diabetic effects of acid hydrolyzed silk peptides, where the amount of peptides in the total amino acid mixture was strictly regulated. Using in vitro diabetes models, silk peptide-containing amino acid mixtures of 5.60% (G5), 11.30% (G10), 14.50% (G15), and 20.50% (G20) were examined separately in order to determine whether they have biological activities. According to our results, a cytoprotective effect was observed following treatment of interleukin-1beta in RINm5f pancreas beta-cells. As a consequence, Bax, a pro-apoptotic gene, was down-regulated, while Bcl-2, a pro-survival gene, was retained at normal level. Results of the 4',6-diamidino-2-phentylindole (DAPI) staining assay confirmed that G20 has a better cytoprotective effect. Insulin release from RINm5f cells showed a significant increase following treatment with G5-G20, suggesting that silk peptide effectively regulated and induced insulin production. Single treatment with G5-G20 resulted in enhanced glucose uptake in L6 skeletal muscle cells. In addition, a higher amount of each group inhibited the activity of alpha-glucosidase. In summary, these data suggest that silk peptide may have an anti-diabetic effect through protection of pancreas beta-cells and enhancement of insulin release, which showed a close association with Type 1 diabetes mellitus (DM), and can improve glucose uptake, which was the major target for therapy of Type 2 diabetes. Taken together, we concluded that acid hydrolyzed silk peptides can be used effectively for control of blood sugar metabolism via improvement of the problematic indices of Type 1 and Type 2 DM.

Keyword

silk peptide; diabetes mellitus; cytoprotection; insulin; glucose uptake

MeSH Terms

alpha-Glucosidases
Blood Glucose
Cytoprotection
Diabetes Mellitus
Diabetes Mellitus, Type 1
Glucose
Insulin
Interleukin-1beta
Muscle Cells
Muscle, Skeletal
Muscles
Pancreas
Peptides
Silk
Up-Regulation
Blood Glucose
Glucose
Insulin
Interleukin-1beta
Peptides
Silk
alpha-Glucosidases