Andrographolide-releasing collagen scaffold enhance the ability of chondrocytes to maintain their specific phenotype under inflammatory environment / 生物医学工程学杂志

ABSTRACT

The aim of this article is to study how andrographolide-releasing collagen scaffolds influence rabbit articular chondrocytes in maintaining their specific phenotype under inflammatory environment. Physical blending combined with vacuum freeze-drying method was utilized to prepare the andrographolide-releasing collagen scaffold. The characteristics of scaffold including its surface morphology and porosity were detected with environmental scanning electron microscope (ESEM) and a density instrument. Then, the release of andrographolide from prepared scaffolds was measured by UV-visible spectroscopy. Rabbit chondrocytes were isolated and cultured and seeded on andrographolide-releasing collagen scaffolds. Following culture with normal medium for 3 d, seeded chondrocytes were cultured with medium containing interleukin-1 beta (IL-1β) to stimulate inflammation for 7 d. The proliferation, morphology and gene transcription of tested chondrocytes were detected with Alamar Blue assay, fluorescein diacetate (FDA) staining and reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR) test respectively. The results showed that the collagen scaffolds prepared by vacuum freeze-dry possess a high porosity close to 96%, and well-interconnected chambers around (120.7±17.8) μm. The andrographolide-releasing collagen scaffold continuously released andrographolide to the PBS solution within 15 d, and collagen scaffolds containing 2.22% andrographolide significantly inhibit the proliferation of chondrocytes. Compared with collagen scaffolds, 0.44% andrographolide-containing collagen scaffolds facilitate chondrocytes to keep specific normal morphologies following 7 d IL-1β induction. The results obtained by RT-qPCR confirmed this effect by enhancing the transcription of tissue inhibitor of metalloproteinase-1 ( ), collagen II ( ), aggrecan ( ) and the ratio of / collagen I( ), meanwhile, reversing the promoted transcription of matrix metalloproteinase-1 ( ) and matrix metalloproteinase-13 ( ). In conclusion, our research reveals that andrographolide-releasing (0.44%) collagen scaffolds enhance the ability of chondrocytes to maintain their specific morphologies by up-regulating the transcription of genes like , and , while down-regulating the transcription of genes like and which are bad for phenotypic maintenance under IL-1β simulated inflammatory environment. These results implied the potential use of andrographolide-releasing collagen scaffold in osteoarthritic cartilage repair.