Abstract
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.