OBJECTIVETo prepare internalized RGD (iRGD) modified echogenic liposomes containing methotrexate (MTX) and indocyanine green (ICG) (iRGD MTX ICG ELIP) and evaluate its targeting efficiency and inhibitory effect combined with ultrasound on synovial cells.

METHODSiRGD MTX ICG ELIP was prepared by the thin film rehydration and freeze-lyophilization method and its general characteristics and acoustic responsiveness were assessed. The targeting effect of the prepared liposome was observed by assessing its cell uptake in vitro. In a mouse model of rheumatiod arthritis, the targeting effect of the prepared liposome was determined by detecting the fluorescence intensity of the drug in arthrosis. The inhibitory effect of iRGD MTX ICG ELIP combined with ultrasound on synovial MH7A cells in vitro were investigated using CCK8 test.

RESULTSThe average diameter and zeta potential of iRGD MTX ICG ELIP was 134.4∓17.61 nm and 10.07∓4.28 mV, and the entrapment efficiency of MTX and ICG was (62.56∓0.77)% and (95.13∓0.82)%, respectively. With ultrasound exposure, the release of MTX and ICG from iRGD MTX ICG ELIP increased with the ultrasound intensity and with the exposure time. In HUVECs, the uptake efficiency of iRGD MTX ICG ELIP was 1.89 times higher than that of non targeted MTX ICG ELIP (P<0.05). In vivo imaging of mouse joint with rheumatiod arthritis showed that the fluorescence intensity of iRGD MTX ICG ELIP was significantly stronger than that of the non targeted liposome. CCK8 assay showed that iRGD MTX ICG ELIP combined with ultrasound resulted in a survival rate of MH7A cells of (32.49∓3.04)%, significantly lower than the rate of cells treated with iRGD MTX ICG ELIP but without ultrasound (P<0.05).

CONCLUSIONSiRGD MTX ICG ELIP has a suitable particle size and can effectively target HUVECs and the joints with rheumatiod arthritis. With a good drug entrapment efficiency and acoustic responsiveness, the drug loaded liposome shows enhanced inhibitory effect on MH7A cells combined with ultrasound in vitro, suggesting its potential in the treatment of rheumatoid arthritis.