Dietary modulation of fatty acid composition of mast cell phospholipids does not affect histamine release induced by compound 48/80.

Department of Internal Medicine, Maastricht University, The Netherlands.

OBJECTIVE AND DESIGN: In the present study we determined the extent to which the degranulation process in mast cells was related to the fatty acid composition of membrane phospholipids. MATERIAL: Peritoneal mast cells were isolated from Wistar rats (3 groups of 18 animals each), fed for 6 weeks diets which differed in their fatty acid compositions: (i) genuine salmon oil, abundant in (n-3) fatty acids, (ii) sunflower seed oil, rich in (n-6) fatty acids, particularly linoleic acid, and (iii) hydrogenated coconut oil, rich in saturated fatty acids. METHODS: Mast cells (10(6)/ml) were stimulated with various concentrations of the mast cell-degranulating agent, compound 48/80 (0.1-10 micrograms/ml). The extent of mast cell degranulation was quantified by determination of histamine in the supernatants using HPLC techniques. RESULTS: No differences in compound 48/80-induced histamine release between the three dietary groups for any of the concentrations of compound 48/80 tested were found. Analysis of variance followed by Tukey's method for multiple comparisons was used to evaluate the effect of changes in the dietary fat type. CONCLUSION: These findings strongly suggest that in contrast to the formation of eicosanoids, the process of mast cell degranulation by a receptor-independent pathway is not controlled by the fatty acid composition of membrane phospholipids.