Figure 2.

Proliferative pre-adipocytes produce myogenic factors. (a) Conditioned media prepared from CD34⁺/Sca1⁺ primary cell cultures enhanced myogenic differentiation of initial fraction cells. Conditioned media were prepared from 24 h of CD34⁺/Sca1⁺ cell cultures between day 1–2 (Day 1–2), day 2–3 (Day 2–3), day 3–4 (Day 3–4) and day 5–6 (Day 5–6), respectively. The percentage of myogenic nuclei was assessed microscopically on initial fraction cells cultured in conditioned media for 4 days, using cells in DMEM/decomplemented FCS as a control (Control). (b) CD34⁺/Sca1⁺ cell phenotype in cell culture. Isolated CD34⁺/Sca1⁺ cells (Sca1) were cultured in DMEM/decomplemented FCS and micrographs were taken after 2 days (Day 2), 3–4 days (Day 3/4) and 6 days (Day 6), respectively. Insert in (Day 6) represents Oil Red O staining of differentiated adipocytes. (c) Conditioned media from proliferative CD34⁺/Sca1⁺ cells enhanced myogenic differentiation. CD34⁺/Sca1⁺ primary cells were cultured and passaged just prior to confluence. Conditioned media were prepared between day 3 and 4 of primary cell culture (S0), after 1 passage (S1), after 2 passages (S2), and after 3 passages (S3), respectively. The myogenic differentiation was estimated by fluorescence (see details in materials and methods). Statistics: n = 3, t-test P < 0.0001 (**).