Fig. 1

Scheme of animal experimental time lines. 12 weeks old male C57Bl/6J (WT) mice were subjected either to DMM or sham surgery and randomly divided into four groups (SP, αCGRP, lacZ or PBS) each according to type of injection post-surgery. At indicated time points, these groups were subjected to intra-articular (i.a.) injection of 350.000 of either rBMSC-SP, rBMSC-αCGRP, rBMSC-lacZ (in 7 µl PBS) or 7 µl PBS (no cells). At longer follow up times, i.a. injections were either repeated 1 × (8 weeks: total of 2 injections) or 3 × (16 weeks: total of 4 injections). Follow up was finished either after two weeks (early OA stage), eight weeks (full OA stage) and 16 weeks (late OA stage). A day before euthanasia, mice were subjected to motion analysis and directly before euthanasia blood removal for serum marker analysis. After euthanasia, knees were removed for OA scoring, Atomic Force Microscopy (AFM) analysis and nano-CT analysis