Synovial Macrophage Activation Profiles in Experimental Knee Osteoarthritis

To investigate differences in gene expression of synovial macrophages in experimental rat knee post traumatic osteoarthritis. Overall design: 12-week-old Sprague Dawley rats underwent a surgical arthrotomy and induction of post traumatic osteoarthritis via transection of the medial meniscotibial ligament and anterior cruciate ligament or sham surgery consisting of an arthrotomy but no transections. 4- or 12-weeks after surgery, synovial tissue was dissected and enzymatically digested into a single cell suspension. Synovial macrophages were sorted with CD11b/c magnetic beads and isolated using magnet assisted cell sorting technology. biological replicates: n=40 rats underwent synovial arthrotomy and induction of PTOA or sham surgery (n=20 per group) for the 4-week endpoint. N=30 rats underwent synovial arthrotomy and induction of PTOA or sham surgery (n-15 per group) for the 12-week endpoint. To facilitate adequate RNA quantity post cell isolation, synovial tissue (n=4 rats; 4-week, and n=3 rats; 12-week) were pooled into individual enzymatic digestions. 5 pooled samples per condition (PTOA or sham) at 4-weeks post surgery and 4 pooled samples (PTOA or sham) at 12-weeks post surgery were sequenced and used as comparator groups for downstream sequencing analysis.