Xiaojun Zhang1, Zhenming Hu, Jie Hao, Jieliang Shen. 1. Department of Orthopaedic Surgery, First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China. linver-115@163.com
Abstract
OBJECTIVE: To investigate the effect of low-intensity pulsed ultrasound (LIPUS) on the extracellular matrix synthesis of human degenerative nucleus pulposus cells and explore the underlying mechanism. METHODS: The nucleus pulposus cells acquired from human degenerative lumbar intervertebral discs were cultured by monolayer culture and identified. After three passages, the cells were cultured in calcium alginate beads. Experimental groups were stimulated by LIPUS (LIPUS group) for 1 week (20 min/d) or treated with LY294002 simultaneously (LY294002 group), and control group was treated in the same way without LIPUS stimulation. The concentrations of aggrecan and Col2α1 in culture supernatant were detected by ELISA. The expression levels of aggrecan and Col2α1 mRNA were dertermined by RT-PCR. The expression levels of aggrecan, Col2α1, Akt and p-Akt proteins were examined by Western blotting. RESULTS: The concentrations of aggrecan and Col2α1 in the LIPUS group group was significantly higher than those in the control group (P<0.05). The expressions of aggrecan and Col2α1 at both mRNA and protein levels and p-Akt protein significantly increased in the LIPUS group as compared with the control group (P<0.05), but there was no significant difference in the expression of Akt protein between the two groups(P>0.05). The levels of aggrecan and Col2α1 proteins were significantly lower in the LY294002 group than in the LIPUS group (P<0.05). CONCLUSION: The LIPUS can stimulate the extracellular matrix synthesis of degenerative human nucleus pulposus cells cultured in calcium alginate beads via activating PI3K/Akt pathway.
OBJECTIVE: To investigate the effect of low-intensity pulsed ultrasound (LIPUS) on the extracellular matrix synthesis of human degenerative nucleus pulposus cells and explore the underlying mechanism. METHODS: The nucleus pulposus cells acquired from human degenerative lumbar intervertebral discs were cultured by monolayer culture and identified. After three passages, the cells were cultured in calcium alginate beads. Experimental groups were stimulated by LIPUS (LIPUS group) for 1 week (20 min/d) or treated with LY294002 simultaneously (LY294002 group), and control group was treated in the same way without LIPUS stimulation. The concentrations of aggrecan and Col2α1 in culture supernatant were detected by ELISA. The expression levels of aggrecan and Col2α1 mRNA were dertermined by RT-PCR. The expression levels of aggrecan, Col2α1, Akt and p-Akt proteins were examined by Western blotting. RESULTS: The concentrations of aggrecan and Col2α1 in the LIPUS group group was significantly higher than those in the control group (P<0.05). The expressions of aggrecan and Col2α1 at both mRNA and protein levels and p-Akt protein significantly increased in the LIPUS group as compared with the control group (P<0.05), but there was no significant difference in the expression of Akt protein between the two groups(P>0.05). The levels of aggrecan and Col2α1 proteins were significantly lower in the LY294002 group than in the LIPUS group (P<0.05). CONCLUSION: The LIPUS can stimulate the extracellular matrix synthesis of degenerative human nucleus pulposus cells cultured in calcium alginate beads via activating PI3K/Akt pathway.