Imai Yoshiyuki, Miyamoto Kei, An Howard S, Thonar Eugene J-M A, Andersson Gunnar B J, Masuda Koichi
Department of Orthopedic Surgery, Rush Medical College at Rush University Medical Center, Chicago, IL 60612, USA.
Spine (Phila Pa 1976). 2007 May 20;32(12):1303-9; discussion 1310. doi: 10.1097/BRS.0b013e3180593238.
In vitro assessment of the effects of recombinant human osteogenic protein-1 (rhOP-1) on the proteoglycan metabolism of human intervertebral disc cells.
To determine whether rhOP-1 is effective in stimulating the cell proliferation and proteoglycan metabolism of human intervertebral disc cells cultured in alginate beads.
OP-1 has been shown to stimulate the proteoglycan and collagen synthesis of rabbit intervertebral disc cells in vitro. In vivo, a single injection of rhOP-1 restored the disc height of a degenerated disc in the rabbit anular-puncture model. The effect of rhOP-1 on human intervertebral disc cells remains unknown.
Human nucleus pulposus and anulus fibrosus cells were isolated from the discs of 4 cadaveric spines and one surgical specimen. After preculture for 7 days, alginate beads containing nucleus pulposus and anulus fibrosus cells were cultured for 21 days in media containing 10% fetal bovine serum with 0, 100, or 200 ng/mL rhOP-1 and supplements. The synthesis and accumulation of proteoglycans and the DNA content were biochemically assessed.
The addition of rhOP-1 to the media resulted in the prevention of a decreased cell number during culture. Treatment with rhOP-1, compared with the control condition (10% fetal bovine serum), significantly upregulated proteoglycan synthesis and accumulation in alginate beads in all cases tested. A longer exposure over 14 days to rhOP-1 resulted in a pronounced response. The retention of newly-synthesized proteoglycan was higher in the rhOP-1-treated cells than in the control.
rhOP-1 was effective in stimulating the cell proliferation and proteoglycan metabolism of human intervertebral disc cells in vitro. The results supported the hypothesis that an in vivo injection of rhOP-1 may increase the metabolic activity of disc cells or prevent apoptosis of disc cells in a degenerated disc. However, the requirement for a long exposure to rhOP-1 for human cells may suggest the need for a prolonged supply of rhOP-1 by a drug delivery system or by repeated injections.
体外评估重组人骨形成蛋白-1（rhOP-1）对人椎间盘细胞蛋白聚糖代谢的影响。
确定rhOP-1是否能有效刺激在藻酸盐珠中培养的人椎间盘细胞的增殖和蛋白聚糖代谢。
已表明OP-1在体外能刺激兔椎间盘细胞的蛋白聚糖和胶原蛋白合成。在体内，单次注射rhOP-1可恢复兔环状穿刺模型中退变椎间盘的椎间盘高度。rhOP-1对人椎间盘细胞的作用尚不清楚。
从4具尸体脊柱的椎间盘和1个手术标本中分离出人髓核和纤维环细胞。预培养7天后，将含有髓核和纤维环细胞的藻酸盐珠在含有10%胎牛血清、0、100或200 ng/mL rhOP-1及添加剂的培养基中培养21天。对蛋白聚糖的合成与积累及DNA含量进行生化评估。
向培养基中添加rhOP-1可防止培养过程中细胞数量减少。与对照条件（10%胎牛血清）相比，在所有测试情况下，rhOP-1处理均显著上调了藻酸盐珠中蛋白聚糖的合成与积累。在14天以上的时间里，更长时间暴露于rhOP-1会产生明显的反应。rhOP-1处理的细胞中新合成蛋白聚糖的保留率高于对照细胞。
rhOP-1在体外能有效刺激人椎间盘细胞的增殖和蛋白聚糖代谢。这些结果支持了以下假设，即体内注射rhOP-1可能会增加退变椎间盘中椎间盘细胞的代谢活性或防止椎间盘细胞凋亡。然而，人细胞需要长时间暴露于rhOP-1，这可能表明需要通过药物递送系统或重复注射来长期供应rhOP-1。
