Inhibitory effects of sulfonated shale oil fractions on the oxidative burst and Ca++ mobilization in stimulated macrophages.

The effect of sulfonated shale oil fractions on the oxidative burst and the mobilization of intracellular calcium in purified guinea pig peritoneal macrophages was investigated in vitro. Three sulfonated shale oil fractions of varying boiling range, No. 1 = R = 1269 (powder, sodium salt of sulfonated shale oil dark), No. 2 = R 3269 (watery solution, sodium salt of sulfonated shale oil pale, Ichthyol hell), No. 3 = R 2069 (watery solution, ammonium salt of sulfonated shale oil dark, Ichthyol) were investigated. Two of three compounds dose-dependently inhibited leukotriene (LT) B4-induced Ca++ mobilization with complete inhibition at 10 mumol/l. The phorbol ester-stimulated generation of superoxide anion was dose-dependently inhibited by all three compounds with an optimal concentration of 1 to 10 mumol/l and maximal inhibition of 34.7, 39 and 38%. High concentrations of the compounds promoted the release of superoxide anion into the buffer medium. The LTB4-stimulated generation of hydrogen peroxide was also dose-dependently inhibited by all three compounds with maximal inhibition of 34, 40 and 32% with an optimal concentration of 100 mumol/l. Our observations support the hypothesis that sulfonated shale oil fractions are capable of modulating inflammatory responses through inhibition of inflammatory cell functions.