BACKGROUND: Studies show that low-intensity pulsed ultrasound can improve the healing of bone fracture and regulate the cell proliferation and extracellular matrix secretion of cartilage.
OBJECTIVE: To identify the effect of low-intensity pulsed ultrasound on cell proliferation and extracellular matrix secretion of precartilagious stem cells (PCSCs)
METHODS: The precartilagious stem cells were isolated from the neonatal Sprague-Dawley (SD) rats and purified with magnetic activated cell sorting, identified by immunocytochemistry with the specific marker (FGFR-3). Passage 3 cells were divided into 4 groups: Blank control group, 5 minutes per day group, 12 minutes per day group and 20 minutes per day group. The cells were cultured for 24 hours continually after stimulated by LIPU. The cell proliferation was detected by CCK-8 method at the 1st, 3rd and 5th day. The total RNA was collected every 30 minutes after stimulated by low-intensity pulsed ultrasound, and the gene expression of collagen type Ⅱ, Aggrecan, transforming growth factor β1 and Sox9 was detected by real-time polymerase chain reaction.
RESULTS AND CONCLUSION: Low-intensity pulsed ultrasound could promote the proliferation of SD rats PCSCs, and compared with the blank control group on the first day only the 20 minutes per day group showed more obvious proliferation than the other groups, the difference was statistically significant (P < 0.05). Low-intensity pulsed ultrasound can also promote the gene expression of collagen type Ⅱ, Aggrecan, TGF-β1 and Sox9 on SD rats PCSCs significantly. Higher amount of mRNA expression resulted from more stimulation, and the most effective group is 20 minutes per day group. Low-intensity pulsed ultrasound can promote the cell proliferation and extracellular matrix secretion of rat PCSCs. This effect may be mediated by TGF-β1 and Sox9 gene.