Exploration of the Suitable Culture Conditions for Extracellular Microvesicles Derived from Human Mesenchymal Stem Cells / 中国实验血液学杂志

ABSTRACT

OBJECTIVE@#To explore the appropriate procedures for preparing extracellular microvesicles (MV) derived from human mesenchymal stem cells (MSC).@*METHODS@#Human MSCs from umbilical cords were cultured in a serum-free medium and maintained in a basal medium for 72 hours after the cell confluence reached to 80%. The supernatants of cultured cells were collected and MVs were enriched. MVs were identified by flow cytometry and electron microscopy. The total protein amount in MVs was used as a parameter for the content of MVs. The supernatants were adjusted to different pH values, and the output of MVs was detected. The supernatants were also collected for enriching the MV and detecting the protein content of MV after the cells were maintained in the basic medium for different time.@*RESULTS@#Flow cytometric analysis showed that the MVs expressed CD9, CD63 and CD81, morphologically presented round under an electron microscope and the diameter of MV was around 100 nm. After enrichment of MV, the protein content of MVs in the supernatants was 416.8±128.1, 255.4±77.9 and 142.8±46.4 μg per 10 MSC，respectively at pH of supernatant 3, 7 and 9 (P＜0.05). The protein content of the supernatants per 10 MSC was 173.6±44.5, 262.4±49.6 and 364.2±37.8 μg respectively after starvation culture for 48, 72 and 96 hrs (P＜0.05).@*CONCLUSION@#MVs can be readily collected after MSCs were starved for 96 hours, and the pH of the supernatants is adjusted at 3.0.