Bone mediated effects of estradiol and pamidronate on proteoglycan and aggrecan neoepitopes release by human cartilage explants.

<p>A. Proteoglycan release in cartilage supernatants. IL1-β stimulated cartilage explants were cultured with media from bone explants previously cultured with estradiol at 0.01 µM (E-8) or 1 µM (E-6) or pamidronate at 1 µM (PAM) or with control medium (M). Results are the mean ± SEM of 3 different experiments performed in triplicate. B. Aggrecan neoepitopes expression (ARGS³⁷⁴ sequences) in cartilage supernatants. Image of a representative Western blot. The overlying graph represents the mean quantification ± SEM of 3 different experiments. Quantification was done on the 50 kDa bands. *: compared to control, p<0.05. §: compared to IL-1β stimulation of cartilage, p<0.05.</p

OPG exerts protective effects on cartilage catabolism.

<p><b>A.</b> OPG/RANKL mRNA ratio in IL1-β stimulated bone explants cultured with estradiol at 0.01 µM (E-8) and 1 µM (E-6), and with pamidronate (PAM). The graph represents the mRNA ratio to controls in 3 different experiments. <b>B.</b> Effect of OPG blockade by a neutralizing antibody (OPG-ab) on ARGS³⁷⁴ sequences expression in supernatants of cartilage explants cultured with conditioned bone media. Image of a representative Western blot, and the graph shows the mean quantifications ± SEM of 4 different experiments. Quantification was done on the 50 kDa bands. *: p<0.05.</p

Effect of bone resorption inhibitors on bone indices in osteopenic mice with joint instability.

§<p>: compared to controls, p<0.05.</p>*<p>: compared to PBS, p<0.05.</p

Histological assessment of cartilage lesions.

<p>A. OA scored according to the 2010 OARSI recommendations. The score represents the sum of the grades at the tibia and femur in sagittal sections. B. Magnifications of slides stained with safranin-O (40×) in control mice (a: Sham operated knees; b: MNX knees; n = 8) and osteopenic (OP) mice treated with phosphate buffered saline (PBS) (c; n = 10), estradiol (E₂) (d; n = 6), or pamidronate (PAM) (e; n = 5). *: p<0.05.</p