COX-2 expression and activity in L6 myoblasts. A) COX-2 protein content was determined by western blotting in L6 myoblasts under basal conditions (CTRL) or in cells treated with tryptase (representative sample of 4 separate experiments) or with LPS. B) COX-1 and COX-2 activity following trypsin stimulation. C) COX-2 activity was measured by the production of PGF2α through enzyme immunoassay following tryptase and trypsin stimulation. D) L6 myoblast proliferation following incubation with increasing doses of NS-398 in presence of tryptase or trypsin where control wells (not pre-incubated with the inhibitor) represent 0% inhibition (not shown). E) L6 myoblast proliferation following incubation with increasing doses of 15Δ-PGJ2, while control wells received medium only. Each data point represents the mean of five separate experiments (mean ± s.e.m). * Significantly different from control, P < 0.05.