Abstract
Chronic osteomyelitis, a bone infectious disease, is characterized by dysregulation of bone homeostasis, which results in excessive bone resorption. Lipopolysaccharide (LPS) which is a gram-negative endotoxin was shown to inhibit osteoblast differentiation and to induce apoptosis and osteoclasts formation in vitro. While effective therapy against bacteria-induced bone destruction is quite limited, the investigation of potential drugs that restore down-regulated osteoblast function remains a major goal in the prevention of bone destruction in infective bone diseases. This investigation aimed to rescue LPS-induced MC3T3-E1 pre-osteoblastic cell line using the methanolic extract of Cladophora glomerata enriched with Mn(II) ions by biosorption. LPS-induced MC3T3-E1 cultures supplemented with C. glomerata methanolic extract were tested for expression of the main genes and microRNAs involved in the osteogenesis pathway using RT-PCR. Moreover, osteoclastogenesis of 4B12 cells was also investigated by tartrate-resistant acid phosphatase (TRAP) assay. Treatment with algal extract significantly restored LPS-suppressed bone mineralization and the mRNA expression levels of osteoblast-specific genes such as runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP) and osteocalcin (OCN), osteopontin (OPN), miR-27a and miR-29b. The extract also inhibited osteoblast apoptosis, significantly restored the down-regulated expression of Bcl-2, and decreased the loss of MMP and reactive oxygen spices (ROS) production in MC3T3-E1 cells induced by LPS. Furthermore, pre-treatment with algal extract strongly decreased the activation of osteoclast in MC3T3-E1-4B12 coculture system stimulated by LPS. Our findings suggest that C. glomerata enriched with Mn(II) ions may be a potential raw material for the development of drug for preventing abnormal bone loss induced by LPS in bacteria-induced bone osteomyelitis.