Figure 7.

Effect of pentoxifylline pretreatment on TNF-α and IL-1β production by cells harvested from peritoneal cavities and knee joints injected with zymosan. In panels a and b, the mice were injected with saline (S; 0.2 ml mice⁻¹; i.p.) or zymosan (1 mg mouse⁻¹; i.p.), and 15 min later, the peritoneal cells were harvested and incubated in vitro for 12 h. The concentrations of TNF-α (panel a) and IL-1β (panel b) in the supernatants were determined by ELISA. Pentoxifylline (PTF; 0.5 and 1.6 mg kg⁻¹) or vehicle (saline) was given i.p. 30 min prior to zymosan injection. In panels c and d, the animals were injected intra-articular with saline (S; 50 μl cavity⁻¹) or zymosan (1 mg cavity⁻¹; 50 μl) and 2 h later, the articular cavities were washed and the concentrations of TNF-α (panel c) and IL-1β (panel d) in the exudates were determined by ELISA. Pentoxifylline (PTF; 1.6 mg kg⁻¹) or vehicle (saline) was given 30 min before the intra-articular administration of zymosan. Results are reported as means±s.e.m. of four wells and are representative of two different experiments. Asterisks indicate statistically significant differences between groups and respective controls (^*P<0.05; ^**P<0.001).