Connective tissue activation in guinea pig lung fibroblast cultures: regulatory effects of glucocorticoids

Earlier studies showed that guinea pig lung fibroblasts in cell culture could be "activated" by naturally occurring peptides with a resultant increase in glycolysis and glycosaminoglycan formation. Such connective tissue activation (CTA) in human cell systems (synovial, cartilage, dermal) has proved a useful tool for studying the mechanisms of inflammation and dissecting the efficacy and actions of anti-inflammatory drugs. The present study examined the consequences of treating basal and activated guinea pig lung fibroblasts with glucocorticoids. The data indicate that glucocorticoids minimally suppress glycosaminoglycan (GAG) synthesis in nonactivated cultures. Further, CTA was inhibited to only a minor degree in activated lung fibroblast cultures by steroids, and even markedly supraphysiologic concentrations of glucocorticoids were not notably inhibitory. It was of interest that thiols enhanced suppression of incremental GAG synthesis by some glucocorticoids in activated lung fibroblast cultures.