Abstract:

BACKGROUND: In vitro experiments have confirmed that transforming growth factor-β1 (TGF-β1) can promote proteoglycan synthesis and delay intervertebral disc degeneration, but its in vivo role remains unclear. 
OBJECTIVE: To study the effect of local utilization of TGF-β1 on proteoglycan expression in rabbit degenerated lumbar discs.
METHODS: Thirty-six New Zealand white rabbits were divided into two groups randomly, with 6 in control group and 30 in model group. The lumbar structure was destroyed partly in the model group. After 12 weeks, the intervertebral disc degeneration was testified by X-ray in model group. Six rabbits chosen randomly from the model group and all rabbits in the control group were killed and the organizations of the intervertebral discs of L_4-5 were harvested. Meanwhile, the rest rabbits in model group were divided into two groups randomly, which was injected with TGF-β1 saline. The rabbits were killed by 2 and 4 weeks after injection. The contents of proteoglycan in nucleus pulposus were tested by phloroglucinol method. 
RESULTS AND CONCLUSION: The content of proteoglycan in the nucleus pulposus was obviously decreased at 12 weeks after model preparation (P < 0.01). After TGF-β1 injection, the content of proteoglycan was notably increased (P < 0.01). It is suggested that intervertebral injection of TGF-β1 to rabbit can delay intervertebral disc degeneration and enhance the synthesis of proteoglycan in nucleus pulposus.