Objective To investigate the effects of supernatant liquid from cultured mesenchymal stem cells (MSCs) on the lipid accumulation, polarisation, inflammation and apoptosis of macrophages.

Methods The mesenchymal stem cells supernatant liquid (MSCs-SL) was co-cultured with THP-1 macrophages. The THP-1 macrophages activity were detected by MTT assay. The lipid accumulation of THP-1 macrophages were detected by oil red O staining. Real-time PCR (qRT-PCR) was used to detect the expression levels of TNF-α, IL-1β, CD206 and ARG-1. The apoptosis of THP-1 macrophages were detected by Tunel staining.

Results The 20% MSCs-SL could enhanced the lipopolysaccharide-induced macrophage activity (F = 63.70, P ＜ 0.01). After treating the cells with 20% MSCs-SL, no significant effect on lipid accumulation in macrophages was observed (F = 2.26, P ＞ 0.05). The MSCs-SL co-culture group significantly upregulated the mRNA levels of TNF-α (F = 125.90, P ＜ 0.01) and IL-1β (F = 165.00, P ＜ 0.01) under inflammatory conditions and TNF-α (t = 12.60) and IL-1β (t = 8.77, P ＜ 0.01) under M1 polarity conditions, and down-regulated the mRNA level of CD206 in the M2 polar state (t = 6.19, P ＜ 0.05). MSCs-SL treatment could significantly inhibit the macrophage apoptosis.

Conclusions MSCs-SL has no significant effect on lipid accumulation in macrophages, but it can promote the macrophage inflammation and M1 polarization, and inhibit the M2 polarization and apoptosis of macrophages.