Differential effects of cortisol on MRC-5 fibroblasts and hypertrophic LL-29 fibroblasts

Cortisol is a glucocorticoid secreted by the adrenal cortex that helps facilitate the body's response to stress and regulates the immune system. Glucocorticoid receptors can be found on most cell types and as a consequence, cortisol hormone plays an essential role on the body's physiologic systems. Cortisol has been shown to elicit differing responses from normal fibroblasts in comparison to hypertrophic fibroblasts. The purpose of this experiment was to analyze the differential effects of cortisol on normal MRC-5 fetal lung fibroblasts and hypertrophic LL-29 lung fibroblasts from a patient with idiopathic pulmonary fibrosis. The objectives of the experiment are to obtain and culture normal and hypertrophic lung fibroblasts, to challenge cells with subphysiological, physiological, and supraphysiological doses of cortisol (0.01 mu g/dL, 0.2 mu g/dL, 1 mu g/dL) for 24, 48, and 72 hour incubation periods and to analyze cellular activity using the methods of cell count, protein assay, MDA, and morphological evaluation. Data collected from this study demonstrated variable response to cortisol by both cell lines. Striking results revealed that in LL-29 cells, supraphysiological dose of cortisol stimulated cell growth only in the 24-hour incubation period without showing any changes in number of micronucleoli or structural damage. In contrast, MRC-5 cells showed increased growth at a later stage (48 hours) with a dose specific increase with significantly increased micronucleoli numbers. In conclusion, the two cell lines differ in their response to cortisol concentration in a dose and time dependent manner. Cortisol concentrations did not induce structural damage throughout the experiment. These observations could help significantly in minimizing the traumatic side effects induced through stress conditions by employing intervention modalities to regulate systemic cortisol.