Figure 5.

Targeted overexpression of ECM1 in chondrocytes leads to alteration of growth plate in vivo. A) Expression pattern of ECM1 (upper panels) and alteration of hypertrophic zone (lower panels) in growth plate of ECM1 transgenic mice (Col IIa1–ECM1 Tg) compared with WT littermates assayed by histology. Slides from growth plate of WT and transgenic mice were taken, followed by safranin O staining and immunohistochemistry against ECM1; n = 6, respectively. B) Skeletal preparation with alcian blue/alizarin red staining of newborn WT and transgenic mice. Representative pictures were shown as whole-mount view. C) Dual-energy X-ray absorptiometry scan analysis for total bone mineral density (BMD) in WT and transgenic mice at 3 wk. Bone density is significantly lower in male transgenic mice but not in female mice; n = 6 in each group. D) No significant difference in BV/TV is observed between ECM1 transgenic and WT mice assayed by bone morphology analysis of tibia sections. E) Alteration of signals for chondrogenesis-related markers, including ECM1, PTHrP, PGRN, and ADAMTS-7 (TS-7), in growth plate of transgenic mice detected by immunohistochemistry. NS, not significant. Tg:Col IIa1–ECM1 transgenic mice. Values are means ± sd. *P < 0.05 vs. WT control group.