Fig. 4

Prostaglandin production in tendon-derived stromal cells and expression of prostaglandin synthetic enzymes in tendon biopsies. a Representative FACS contour plots showing that cultured tendon-derived stromal cells do not express markers of endothelial cells (CD45) or leukocytes (CD34). b, c Tendon-derived cells from healthy hamstring tendons (HT; n = 8), diseased Achilles tendons (AT; n = 6), and diseased supraspinatus tendons (ST; n = 8) were cultured and treated with medium only or medium containing 10 ng/mL IL-1β for 24 h. Prostaglandins in supernatants were extracted and quantified using LC-MS/MS. Lower limit of quantification was 200 pg/mL. Prostacyclin production was quantified by measuring stable metabolite 6-keto PGF_1α. The bars show median values. Statistical significance was calculated using Kruskal-Wallis test with pairwise post-hoc Mann-Whitney U test. d–g Effect on prostaglandin profile upon inhibition of COX or mPGES-1 in IL-1β-treated tendon cells. Diseased (n = 4, d, e) and healthy (n = 4, f, g) tendon-derived cells were treated with vehicle, IL-1β alone (10 ng/mL), or IL-1β together with either dual COX-1/2 inhibitor naproxen (10 μM), selective COX-2 inhibitor NS-398 (10 μM), or selective mPGES-1 inhibitor CIII (10 μM) for 24 h. Bars show median values. Statistical significance was calculated using paired t test