passages.id: split_4_test_3221_passage
passages.type: progene_text
passages.text: BMMs were cultured with or without M-CSF , and analyzed for expression of OPG and receptor activator of NF-kappaB ( RANK ; receptor for RANKL ) mRNAs by real - time polymerase chain reaction and secretion of OPG by enzyme - linked immunosorbent assay .