CSF1 and arthritic joint disease: To directly address the mechanisms involved in ES-62-mediated modulation of OC responses, BM was cultured with M-CSF and RANKL for 5 days and naïve BM from both DBA/1 and C57BL/6 mouse strains was employed, the latter to allow us to examine the potential for differences in OC differentiation and functional maturation between arthritis-prone and more resistant strains, respectively (28).