(A). Normal proliferation of BM-MSCs at early passage (P3) by MTT assay; (B). Phase contrast microscopic image of BM-MSCs showing the characteristic short, thin fibroblastic morphology; (C). FACS images showing the positive and negative MSC related surface markers; (D, E). Cell proliferation of BM-MSCs that were exposed to arthroscope either as cell-suspension (D) or as cell-pellet (E). Values are expressed as mean ± SEM (n=3). Asterisk indicates significance (p<0.5) compared to the control.