Figure 1.

Chemical structure of ligustrazine and photomicrographs of IVDs stained by safranin-O/fast green. (a) Chemical structure of ligustrazine (tetramethylpyrazine). (b)-(c) Upright posture reduced the heights of IVDs. However, the heights of IVDs increased when ligustrazine pretreatment began seven or nine months after surgery, while meloxicam increased the heights of IVDs when pretreatment started five months after surgery and had no significant effect when pretreatment commenced seven and nine month after surgery. The arrow indicates the quantitative measurements of IVD heights; the bar equals 1000 μm. Each value represents the mean ± S.D of 6 sections. *P < 0.05 compared to model group in the same month.