Oral cell lysates reduce osteoclastogenesis in murine bone marrow cultures

Abstract

Mechanical and thermal cell damage can occur as a consequence of invasive procedures related to drilling, the insertion of dental implants, as well as periodontal treatments. Necrotic cells release the content of their cytoplasm and membrane fragments thereby signaling the need for repair, a process that includes bone resorption by osteoclasts and inflammation. Here we screened lysates from human gingival fibroblasts, HSC2 and TR146 oral squamous carcinoma cell lines, as well as murine IDG-SW3 osteocytic and RAW264.7 macrophage cell lines for their potential to modulate in vitro osteoclastogenesis in murine bone marrow cultures. We also tested the impact of necrotic lysates to modulate the expression of inflammatory cues in murine ST2 bone marrow stromal cells. We report here that independent of human or murine origin, all cell lysates significantly reduced in vitro osteoclastogenesis in bone marrow cultures; as indicated by the expression of the osteoclast marker genes cathepsin K and tartrate-resistant acid phosphatase, and the respective histochemical staining in multinucleated cells. We also found that lysates from HSC2 and TR146 cells greatly pushed the expression of CCL2, CCL5, CXCL1, IL1, and IL6 in ST2 cells. These findings suggest that oral cell lysates reduce in vitro osteoclastogenesis but only damaged oral squamous carcinoma cells can force stromal cells to produce an inflammatory environment.