The role of tissue mast cells in polyacrylamide gel-induced inflammation in mice

Abstract.

Objective and Design: In the present study, we investigated the role of mast cells in a model of polyacrylamide gel (PAG)-induced inflammation in mice.¶Subjects: Balb/c mice and two strains of mast cell deficient mice (WBB6F₁/J-W/W^v, WCB6F₁/J-S1/S1^d).¶Treatment: Various quantities of polyacrylamide gel (Bio-Gel P4) were injected subcutaneously in the backs of mice.¶Methods: Five hours after the injection of PAG the animals were euthanized, the injection sites lavaged and levels of LTB₄, PGE₂, TNFα and cells were determined.¶Results: Subcutaneous injection of PAG caused a time-dependent response characterized by the accumulation of inflammatory cells peaking at 10 h and the formation of LTB₄, PGE₂ and TNFα, peaking at 5 h. PAG injection into W/W^v or SL/SL^d mice (mice lacking mast cells) resulted in an attenuated 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 in the levels of TNFα found.¶Conclusions: These data suggest that mast cells play a prominent role in the PMN influx, TNFα production and eicosanoid formation in the PAG-induced inflammatory response.