Inhibitory Effect of Tilapia Head Phospholipid on RANKL-Induced RAW264.7 Cell Differentiation and Mechanism of Osteoclast Apoptosis Induced by It

This study was performed to investigate the effect of tilapia head phospholipid (TH-PL) on biological functions in osteoclasts. Total lipids from tilapia head were extracted with organic solvents and separated by silica gel column chromatography to obtain TH-PL. Its properties and structure were partially analyzed by thin layer chromatography (TLC),Fourier transform infrared spectroscopy (FTIR) and gas chromatography. In addition, an osteoclast model was established by inducing the differentiation of RAW264.7 macrophages in vitro with receptor activator for nuclear factor-κB ligand(RANKL). The effect of TH-PL on the differentiation of RAW264.7 macrophages into osteoclasts was explored by tartrate resistant acid phosphatase (TRAP) staining. Fluorescent staining, Western blotting and flow cytometry were used to detect osteoclast apoptosis. The results showed that TH-PL accounted for 1.52% of the dry mass of tilapia heads. TLC and FTIR determined that the as-prepared sample was phospholipid and rich in unsaturated fatty acids, accounting for 38% of the total fatty acids. TRAP staining experiments confirmed that TH-PL at doses of 50 and 100 μg/mL significantly inhibited the differentiation of RAW264.7 macrophages into osteoclasts. Furthermore, TH-PL promoted osteoclast apoptosis by reducing mitochondrial transmembrane potential and increasing the expression of caspase-3 in cells. In conclusion, in vitro cell experiments demonstrated that TH-PL could significantly inhibit osteoclast differentiation and promote osteoclast apoptosis. © 2020, China Food Publishing Company. All right reserved.