The Extract of Fructus Psoraleae Promotes Viability and Cartilaginous Formation of Rat Chondrocytes In Vitro

This study aimed to investigate the extract components of FP on rat chondrocyte function and cartilaginous formation in vitro. Petroleum ether extract (P-e) of FP extract components was selected to treat Sprague-Dawley rat chondrocytes. Cell viability was tested with different concentrations (0.1, 1, 10, and 100 μg/mL) of P-e treatment. Concentrations of 0.1 and 1 μg/mL P-e conditioned culture mediums were used for treating chondrocytes in experiments. Cell proliferation was measured via DNA incorporation assay. Type II collagen, aggrecan, and Sox-9 genes expression levels were measured with RT-PCR. Additionally, cartilaginous formation was analyzed with type II collagen immunofluorescence, H&E, and alcian blue staining. Concentrations of 0.1 and 1 μg/mL P-e showed low cytotoxicity and demonstrated stimulatory effects on chondrocyte proliferation in early stages. Following 6 days of P-e culture, aggrecan and Sox-9 gene expression levels of the 1 μg/mL P-e group were upregulated by 1.82- (p < 0.05) and 2.06-fold (p < 0.05), respectively, versus controls. Moreover, 1 μg/mL P-e significantly stimulated cell aggregation and type II collagen deposits after 1 week of treatment. Noteworthy, tight cartilaginous structures formed in the 10-day 1 μg/mL P-e conditioned culture. These findings suggest that P-e has the potential to treat cartilage degeneration induced by chondrocyte failure.