Lubricin expression in human BM MSCs after pellet culture.
(A) Schema for the study of in vitro chondrogenesis. BM MSCs were prepared from 5 donors. 2.5 × 105 human BM MSCs at passage 2 were pelleted and cultured in chondrogenic medium for 7 or 21 days. (B) Histological sections of cartilage pellets at day 21 stained with Safranin-O/Fast Green. (C) Cartilage pellets immunostained with lubricin. (D) Cartilage pellets immunostained without primary lubricin antibody as negative control. (E) Extent score for lubricin positive cell rate [37] (n = 5, *p<0.05 by the Wilcoxon’s signed rank test). (F) Transmission electron microscopy (TEM) images for pellets at 21 days. (G) Real time PCR analysis for MSCs 7 days after monolayer (Mono) and pellet culture (Pellet). RNA was prepared from 500,000 MSCs or 2 pellets from 5 donors respectively. Gene expression levels in MSCs after monolayer culture were normalized as 1. (H) Western blotting image for lubricin protein of medium obtained 21 days after monolayer and pellet culture.
