Constitutive expression of IL-6 and IL-8 mRNA. mRNA was extracted from T-HPMC and P-HPMC cultured in CM alone. RT-PCR was performed using primers specific for IL-6 or IL-8 (see Materials and methods). Samples were resolved in 1·5% agarose gel. Lane 1, DNA marker (φX174/ Hae III); Lane 2, IL-6 mRNA of T-HPMC; Lane 3, IL-6 mRNA of P-HPMC; Lane 4, IL-8 mRNA of T-HPMC; Lane 5, IL-8 mRNA of P-HPMC; Lane 6, negative control for IL-6; Lane 7, negative control for IL-8.