Effects of loading frequency on matrix synthesis of annulus fibrosus cells in an intervertebral disc perfusion culture system

English Keywords:Intervertebral disc  Degeneration  Organ culture  Loading  Frequency

English Abstract:

  【Abstract】 Objectives: To investigate the effects of loading frequency on matrix synthesis of annulus fibrosus (AF) cells. Methods: Discs from porcine(4-6 months old) were isolated and randomly divided into control group (no loading) and loading groups(0.1Hz, 0.5Hz, 1Hz, 3Hz and 5Hz group, respectively). All discs were put in tissue culture chamber for perfusion culturing. No loading was applied to the discs in the control group while different loading frequencies(0.1Hz, 0.5Hz, 1 Hz, 3Hz and 5Hz, respectively) were applied to the discs in the loading groups. After culturing for 5 days, the full-thickness AF tissues were used for the analysis of HE staining, alcian blue staining, matrix genes(Aggrecan, Collagen Ⅰ, collagen Ⅱ) expression, GAG content and HYP content. Results: After 5 days, AF in each group remained the natural lamellar structure. Compared with the control group, stronger intensity of alcian blue staining, up-regulated expression of matrix genes and increased GAG content and HYP content were observed in loading groups except for the 5Hz group. When compared among loading groups, the alcian blue staining intensity, expression of matrix genes, GAG content and HYP content in 5Hz group all decreased compared with those of other loading groups(0.1Hz, 0.5Hz, 1Hz and 3Hz group). Conclusions: Under condition of intervertebral disc perfusion culturing, matrix synthesis of AF cells is influenced by loading frequency, which increases at low frequency(0.1-3Hz) and decreases at high frequency(5Hz).