Carrageenin-Induced Pleurisy in Rats

Purpose: To investigate the effects and potential mechanisms of Shaoyao-Gangcao-Tang (SGT) on acute and resolution phases of carrageenin-induced pleurisy in rats. Methods: To determine the effects of SGT at 2 h, Sprague-Dawley rats received injection of 0.2 ml of 1 % λ-carrageenin into the pleural cavity after treatment with 4.0, 13.3 and 40.0 g/kg SGT for three days. At 2 h after pleurisy induction, exudate volume, total cell number, prostaglandin E2 (PGE2) production and cyclooxygenase-2 (COX-2) protein expression were measured. To determine the effects at 48 h, the rats were treated with SGT at 24, 36 and 46 h after injection of λ-carrageenin into the pleural cavity, and the exudate volume, total cell number, 15-deoxy-Δ12, 14-PGJ2 (15d-PGJ2) production and COX-2 protein expression were evaluated. Results: At 2 h after pleurisy induction, 13.3 and 40.0 g/kg SGT significantly decreased exudate volume by 34 (p < 0.05) and b 4 0 % (p < 0.01), total cell number by 27 (p < 0.05) and 41 % (p < 0.01), PGE2 production by 17 (p < 0.05) and 35 % (p < 0.01), as well as COX-2 protein expression by 21 (p < 0.01) and 43 % (p < 0.01) compared with control group treated with saline. At 48 h after pleurisy induction