Background Although exosomes are widely involved in intercellular communication and information communication, the targeting and functions of exosomes from different sources may be different. There are few studies on the targeting of exosomes from different cell sources to osteoporotic bone tissues. Up to now, studies have found that some cell-derived exosomes have targeting and repair effects on damaged bone tissue.
Objective To explore the bone targeting properties of exosomes from different cell sources in osteoporotic mice.
Methods Mesenchymal stem cells (MSC), osteoblast precursor cells (MC-3T3-E1), breast cancer cells (4T1), renal epithelial cells (293T) were cultured in vitro, and then exosomes were extracted from the supernatant. Exosomes were stained with Dir fluorescent dye, then injected intravenously into osteoporotic mice. The distribution of exosomes in vivo and in vitro, and the aggregation of different exosomes in the femur of mice were observed.
Results Dynamic observation of fluorescence in vivo showed that exosomes derived from MSC and MC-3T3-E1 could accumulate significantly in mice femur and reached the peak of aggregation on the third day. Exosomes derived from 4T1 and 293T cells did not aggregate. The mice were sacrificed on the 3rd day, and the lower limb bones were dissected for in vivo imaging and femoral pathological section staining. The results showed that MSC-derived exosomes gathered most heavily in the femur, followed by MC-3T3-E1, but 4T1 and 293T were not.
Conclusion Exosomes derived from MSC and MC-3T3-E1 have bone targeting properties, while exosomes derived from 4T1 and 293T do not have.
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