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Biomacromolecules have been used as templates to grow hydroxyapatite crystals (HAps) by biomineralization to fabricate mineralized materials for potential application in bone tissue engineering. Silk sericin is a protein with features desirable as a biomaterial, such as increased hydrophilicity and biodegradation. Mineralization of the silk sericin from Antheraea pernyi (A. pernyi) silkworm has rarely been reported. Here, for the first time, nucleation of HAps on A. pernyi silk sericin (AS) was attempted through a wet precipitation method and consequently the cell viability and osteogenic differentiation of BMSCs on mineralized AS were investigated. It was found that AS mediated the nucleation of HAps in the form of nanoneedles while self-assembling into β-sheet conformation, leading to the formation of a biomineralized protein based biomaterial. The cell viability assay of BMSCs showed that the mineralization of AS stimulated cell adhesion and proliferation, showing that the resultant AS biomaterial is biocompatible. The differentiation assay confirmed that the mineralized AS significantly promoted the osteogenic differentiation of BMSCs when compared to nonmineralized AS as well as other types of sericin (B. mori sericin), suggesting that the resultant mineralized AS biomaterial has potential in promoting bone formation. This result represented the first work proving the osteogenic differentiation of BMSCs directed by silk sericin. Therefore, the biomineralization of A. pernyi silk sericin coupled with seeding BMSCs on the resultant mineralized biomaterials is a useful strategy to develop the potential application of this unexplored silk sericin in the field of bone tissue engineering. This study lays the foundation for the use of A. pernyi silk sericin as a potential scaffold for tissue engineering.

Glucose and lipid metabolism disorder in diabetes mellitus often causes damage to multiple tissues and organs. Diabetes mellitus is beneficially affected by quercetin. However, its concrete mechanisms are yet to be fully elucidated. In our study, diabetes was induced in Sprague-Dawley rats by STZ injection. The rats were randomly divided into normal control, diabetic model, low-dose quercetin treatment, high-dose quercetin treatment, and pioglitazone treatment groups. Fasting blood glucose was collected to evaluate diabetes. Immunohistochemistry and fluorometric assay were performed to explore SIRT1. Akt levels were measured through immunoprecipitation and Western blot. After 12 weeks of quercetin treatment, the biochemical parameters of glucose and lipid metabolism improved to varying degrees. Hepatic histomorphological injury was alleviated, and hepatic glycogen content was increased. The expression and activity of hepatic SIRT1 were enhanced, and Akt was activated by phosphorylation and deacetylation. These results suggested that the beneficial effects of quercetin on glucose and lipid metabolism disorder are probably associated with the upregulated activity and protein level of SIRT1 and its influence on Akt signaling pathway. Hence, quercetin shows potential for the treatment of glucose and lipid metabolism disorder in diabetes mellitus.

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