FIGURE 1.
PGD2 and PGJ2 induce HA synthesis in human orbital fibroblasts. A, confluent strains of human orbital fibroblasts (OF1 and OF2) were cultured in RPMI 1640 with 0.5% FBS for 3 days prior to treatment with PGJ2, PGD2, or vehicle (DMSO) for 18 h. The cell culture medium was assayed for HA by an HA ELISA as described under ”Experimental Procedures.“ There was a significant increase in HA production by two strains of orbital fibroblasts following treatment with PGD2 (1–5 μm) and PGJ2 (2 μm). The experiment was performed in triplicate. *, p < 0.05; **, p < 0.01; ***, p < 0.001 compared with vehicle control. #, p < 0.05; ###, p < 0.001, OF1 versus OF2. Results are expressed as the mean ± S.D. (error bars). B, agarose gel HA analysis: Orbital fibroblasts (OF1 and OF2) were cultured in RPMI 1640 with 2% FBS for 3 days and then treated with 5 μm PGD2 (D2) or vehicle (V) for 18 h, and the conditioned medium was analyzed by agarose gel electrophoresis. Both OF1 and OF2 exhibited basal HA (lanes 3 and 5, respectively; blue). When treated with PGD2, there was an increase in color intensity, indicating increased HA production (lanes 4 and 6; compare with lanes 3 and 5). A Streptomyces hyaluronidase-digested sample (HA'ase) (from PGD2-treated OF2) was included as a negative control (lane 7).