Steroid-associated osteonecrosis animal model in rats

Zheng, Li-Zhen; Wang, Jia-Li; Kong, Ling; Huang, Le; Tian, Li; Pang, Qian-Qian; Wang, Xin-Luan; Qin, Ling

Rats of the SAON group were lethargic and anorexic at the first week after administration of LPS. Two rats died at day (D) dense adipocytes in yellow marrow in the distal tibia of normal control rats; (E) 2 weeks after SAON induction, oedema (black arrow) was shown in yellow marrow in the distal tibia; (F) 6 weeks after SAON induction, more oedema (black arrow) appeared in yellow marrow in the distal tibia; (G) TRAP staining showed osteoclast (red arrow) in normal control group; (H) TRAP staining showed osteoclast (red arrow) 2 weeks after SAON induction the proximal tibia; (I) TRAP staining showed osteoclast (red arrow) 6 weeks after SAON induction in the proximal tibia. Histomorphometry results showed significantly lower osteoblast surface (Ob. S/BS) in the SAON group in both week 2 and week 6 in the proximal tibia (refer to A, B and C), significantly higher osteoclast number (N.Oc/ BS) in the SAON group in week 2 in the proximal tibia (refer to G, H and I) and significantly higher marrow fat fraction in the proximal tibia of the SAON group in both week 2 and week 6 (refer to A, B and C). The marrow fat faction was significantly higher in week 6 than that in week 2 in the SAON group in the proximal tibia (refer to B and C). Typical marrow without oedema in the normal control group, obvious oedema in the SAON group in both week 2 and week 6 and significantly higher oedema in SAON group in week 6 than that in week 2 in the distal tibia were observed (refer to D, E and F). (*: p < 0.05, **: p < 0.01, n Z 6). ONþ Z osteonecrosis-positive; ON-Z osteonecrosis-negative; SAON Z steroid-associated osteonecrosis; TRAP Z tartrate-resistant acid phosphatase.