THE ROLE OF TISSUE MAST-CELLS IN POLYACRYLAMIDE GEL-INDUCED INFLAMMATION IN MICE

Objective and Design. In the present study, we investigated the role o f mast cells in a model of polyacrylamide gel (PAG)-induced inflammati on in mice. Subjects. Balb/c mice and two strains of mast cell deficie nt mice (WBB6F(1)/J-W/W-V, WCBb6F(1)/J-S1/S1(d)). Treatment: Various q uantities of polyacrylamide gel (Bio-Gel P4) were injected subcutaneou sly in the backs of mice. Methods: Five hours after the injection of P AG the animals were euthanized, the injection sites lavaged and levels of LTB4, PGE(2), TNF alpha and cells were determined. Results: Subcut aneous injection of PAG caused a time-dependent response characterized by the accumulation of inflammatory cells peaking at 10 h and the for mation of LTB4, PGE(2) and TNF alpha, peaking at 5 h. PAG injection in to W/W-V or SL/SLd mice (mice lacking mast cells) resulted in an atten uated response, i.e. LTB4 levels were reduced by 60% and minimal cell influx was seen. The lack of mast cells caused about a 30% reduction i n the levels of TNF alpha found. Conclusions: These data suggest that mast cells play a prominent role in the PMN influx, TNF alpha producti on and eicosanoid formation in the PAG-induced inflammatory response.