Quantitative μCT Analysis of Tibial Microstructural Parameters.

<p>Quantitative μCT Analysis of Tibial Microstructural Parameters.</p

Immunohistochemical Staining for IGF-1R and PTH1R.

<p>The first three rows are representative images of the bone marrow of left tibias treated with <i>Igf-1r</i> siRNA and IGF-1 or <i>Pth1r</i> siRNA and rhPTH (1–34). The bottom row represents the isotype control for the anti-IGF-1R and anti-PTH1R antibodies. Scale bar = 50 μm.</p

<i>Pth1r</i> and <i>Igf-1r</i> mRNA Expression Levels After siRNA Transfection.

<p>The real-time PCR results showed that <i>Pth1r</i> and <i>Igf-1r</i> mRNA expression levels were significantly diminished in the left tibia compared with the right tibia (I-1-1 and P-1-1, one injection for one week; I-1-2 and P-1-2, one injection for two weeks; I-2-2 and P-2-2, two injections over two weeks). *p<0.01, **p<0.05 vs. the right tibia.</p

Representative Images of Double Fluorochrome Labeling.

<p>In the <i>Igf-1r</i> siRNA transfection group, the distance between the two labels in the left tibias treated with <i>Igf-1r</i> siRNA and IGF-1 was significantly shorter than that in the right tibias treated with IGF-1 only. In the <i>Pth1r</i> siRNA transfection group, this distance was also markedly decreased in the left tibias treated with <i>Pth1r</i> siRNA and rhPTH (1–34) compared to the right tibias treated with rhPTH (1–34) only. Scale bar = 20 μm.</p

Animal Treatment Protocol and Images of the Intraosseous Injection Location.

<p>(A) Animal treatment protocol. (B) Anteroposterior and (D) lateral view of the minimally invasive puncture. The entry point was located at the front of the tibial intercondylar eminence, and the needle path penetrated the tibial plateau parallel to the long axis of the tibia. Representative (C) anteroposterior and (E) lateral X-ray radiographs of the tibia.</p

Maximum Force in the Three-point Bending Biomechanical Test.

<p>In the <i>Igf-1r</i> and <i>Pth1r</i> siRNA transfection groups, the mechanical properties of the left tibias, which received <i>Igf-1r</i> or <i>Pth1r</i> siRNA injections, were dramatically diminished compared to the right tibias (I-1-1 and P-1-1, one injection for one week; I-1-2 and P-1-2, one injection for two weeks; I-2-2 and P-2-2, two injections over two weeks). *p<0.05 and **p<0.01.</p

Quantification of MARs.

<p>In the <i>Igf-1r</i> and <i>Pth1r</i> siRNA transfection groups, quantification of the MAR revealed that <i>Igf-1r</i> or <i>Pth1r</i> siRNA injection in the left tibias dramatically reduced the bone formation rate compared to the right tibias treated with IGF-1 or rhPTH (1–34) only (I-1-1 and P-1-1, one injection for one week; I-1-2 and P-1-2, one injection for two weeks; I-2-2 and P-2-2, two injections over two weeks). *p<0.05 and **p<0.01.</p

Representative Three-dimensional Trabecular Architecture of the Tibia After <i>Pth1r</i> or <i>Igf-1r</i> siRNA Injection.

<p>In the <i>Igf-1r</i> siRNA transfection groups, the trabeculae in the left tibias treated with <i>Igf-1r</i> siRNA and IGF-1 were dramatically weakened compared to those in the right tibias treated with IGF-1 only. In the <i>Pth1r</i> siRNA transfection groups, the trabeculae in the left tibias treated with <i>Pth1r</i> siRNA and rhPTH (1–34) were also significantly weakened compared to those in the right tibias treated with rhPTH (1–34) only.</p

Representative Photomicrographs of Undecalcified Sections Stained with Goldner’s Trichrome.

<p>In the left tibias treated with <i>Igf-1r</i> or <i>Pth1r</i> siRNA, osteoid accounted for a very large proportion, which was obviously greater than that in the right tibias, in which the majority was mature trabecular bone. Mature trabecular bone and osteoid are stained green and red, respectively. Scale bar = 50 μm.</p

BMD Changes After Local Intraosseous Injection of <i>Pth1r</i> or <i>Igf-1r</i> siRNA.

<p>I-1-1 and P-1-1, one injection for one week; I-1-2 and P-1-2, one injection for two weeks; I-2-2 and P-2-2, two injections over two weeks. *p<0.01.</p