Mesenchymal stem cells derived from rat bone marrow (rMSCs) could proliferate and grow into cartilage-forming cells on scaffolds made from silk protein and chitosan1. Such scaffolds could be useful in tissue engineering for repairing worn-out cartilage in bone diseases.

Tissue engineering using MSCs has significant potential for cartilage regeneration. However, researchers have previously lacked a suitable scaffold on which to grow cartilage-forming cells from MSCs. To make biocompatible three-dimensional scaffolds, the researchers used silk fibroin (SF) from mulberry silkworm Bombyx mori (BM), non-mulberry silkworm Antheraea myliita (AM) and chitosan (CS). They prepared two pure SF-based scaffolds (SF-BM and SF-AM) and one blended scaffold (SF-CS).

The rMSCs exhibited better attachment to SF-CS and SF-AM scaffolds than to the SF-BM scaffold, with enhanced extracellular matrix production.

The growth medium was rich in transforming grown factor-b1 and dexamethasone, thus allowing the differentiation of rMSCs into chondrocytes, a type of cartilage-forming cells. The SF-CS and SF-AM scaffolds, with their higher degree of porosity and larger pore size, nourished the cells better than SF-BM scaffolds. The cells grown on SF-CS and SF-AM scaffolds also exhibited a higher expression of genes and proteins specific to chondrocytes.

"The SF-CS and SF-AM scaffolds can aid the growth of cartilage by providing a proper three-dimensional microenvironment for the differentiation of MSCs into chondrocytes, offering a novel route for cartilage tissue engineering," says lead researcher Subhas Kundu.