Placenta-derived mesenchymal stem cells (Jinan university)

The placentas of clinically normal pregnancies were excised and washed to remove excess blood. The internal area from the fetal side of central placenta lobules was minced, digested and trypsinized, and then prepared as both single-cell suspensions and as small digested residues. The resulting cells were cultured in low-glucose DMEM supplemented with  fetal bovine serum (FBS; 15%), penicillin (100 U/ml), and streptomycin (100 μg/ml). After 5 days in culture, the small cell residues were removed and the cells were cultured for 4-5 weeks until the fibroblast-like cell colonies were 50% confluent. Then, they were digested and cultured in a new tissue culture plate in the same medium, supplemented with 10% filtered supernatant from the previous passage.  The cells were analysed after five passages.