Effects of Panax ginseng-containing herbal plasters on compressed intervertebral discs in an in vivo rat tail model

Background Tienchi ( Panax notoginseng ) has been used in conservative treatments for back pain as a major ingredient of many herbal medicines. This study aims to investigate the effects of a herbal medicine containing tienchi on compressed intervertebral discs in rats. Methods Using an in vivo rat tail model, intervertebral disc compression was simulated in the caudal 8–9 discs of 25 rats by continuous static compression (11 N) for 2 weeks. An herbal medicine plaster (in which the major ingredient was tienchi ) was externally applied to the compressed disc (n=9) for three weeks, and held in place by an adhesive bandage, in animals in the Chinese Medicine (CM) group. The effect of the bandage was evaluated in a separate placebo group (n=9), while no intervention with unrestricted motion was provided to rats in an additional control group (n=7). Disc structural properties were quantified by in vivo disc height measurement and in vitro morphological analysis. Results Disc height decreased after the application of compression ( P < 0.001). The disc height decreased continuously in the control ( P = 0.006) and placebo ( P = 0.003) groups, but was maintained in the CM group ( P = 0.494). No obvious differences in disc morphology were observed among the three groups ( P = 0.896). Conclusion The tienchi -containing herbal plaster had no significant effect on the morphology of compressed discs, but maintained disc height in rats.