Effect of concentrated growth factor on repair of fibrous annulus of intervertebral disc in rats

English Keywords:Concentrated growth factors(CGF)  Rat intervertebral disc rupture model  Intervertebral disc injury  Disc annulus repair

English Abstract:

  【Abstract】 Objectives: To investigate the effect of concentrated growth factor(CGF) on the repairation of damaged intervertebral disc annulus in rats. Methods: First, 4 adult Sprague-Dawley(SD) female rats were selected, 6-7 weeks old, weight 200-250g, blood was collected from the rats′ abdominal veins after anesthesia and processed through centrifugation to isolate CGF. Then 36 adult SD female rats were selected from the same batch rats, and were randomly assigned into three groups of control group, surgery group, and CGF group, with 12 rats per group. In the blank group, only the L4/5 discs were exposed and no other treatment was done. In the control group, only the L4/5 discs were exposed and no other treatment was done. The surgery group had a disc puncture performed at the L4/5 level to induce disc rupture; In the CGF group, after modeling, membrane was made with CGF to cover over the annulus fibrosus defect. Postoperative care included standard antiseptic and analgesic treatments. At 4 and 6 weeks postoperatively, tissues from the L4/5 level were harvested for morphological assessment via hematoxylin and eosin(HE) and type Ⅱ collagen immunohistochemistry staining. Results: Postoperatively at both 4 and 6 weeks, with the preservation of the nucleus pulposus′s integrity, the surgery group demonstrated pronounced annulus fibrosus damage at the L4/5 disc compared to the control group. In contrast, the CGF group showed a significant decrease in annulus fibrosus damage relative to the surgery group. HE staining of disc sections revealed that the CGF group had markedly improved annulus fibrosus healing compared to the surgery group. The immunohistochemistry of type Ⅱ collagenase protein of intervertebral disc in each group at 6 weeks after operation indicated that the damage of fibrous ring in the surgery group was more serious than that in the other two groups, and the expression of type Ⅱ collagenase protein was concentrated in the damaged site. Compared with the surgery group, the annulus fibrosus damage was lighter in the CGF group, and the expression of type Ⅱ collagenase protein was also concentrated in the damaged site. Conclusions: CGF can effectively promote the repair of damaged intervertebral disc annulus fibrosus.