Effects of treatments with MTX alone or with supplementary folinic acid (FA) for 6 weeks on overall structures of rat tibia.

<p>H&E staining of rat tibia from control (A), MTX-treated (B) and MTX+FA treated rats (C) at week 6. GP = growth plate, PS = primary spongiosa, SS = secondary spongiosa. H&E staining of growth plates from week 6 control (D), MTX-treated (E) and MTX+FA (F) treated rats. R = resting zone, P = proliferative zone and H = hypertrophic zone. (G) BrdU labeling (arrows) of chondrocytes at proliferative zone of growth plate. (H) Treatment effects on columnar chondrocyte number, which were measured along the red dotted line. (I) Treatment effects on growth plate chondrocyte proliferation. Scale bars on panels A–C = 500µm, D–F = 250 µm and G = 150 µm.