Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Dual Regulating Effect of Shaoyao-Gangcao-Tang on COX-2 expression in Acute and Resolution Phases of Carrageenin-Induced Pleurisy in Rats

Gang Chen^1,2,3 , Ming-Liang Tan^1,2,3, Xue Gao^1,2,3, Ping Jia⁴

¹Chongqing Key Laboratory of Nature Medicine Research; ²Chongqing Key Laboratory of Catalysis and Functional Organic Molecules; ³Research Center of Medical Chemistry and Chemical Biology, Chongqing Technology and Business University, Chongqing 400067; ⁴Department of Combination of Chinese and Western Medicine, the First Affiliated Hospital of Chongqing University of Medical Sciences, Chongqing 400016, PR China.

For correspondence:- Gang Chen Email: gangchtcm@hotmail.com Tel:+862362768059

Received: 5 May 2012 Accepted: 30 June 2013 Published: 18 October 2013

Citation: Chen G, Tan M, Gao X, Jia P. Dual Regulating Effect of Shaoyao-Gangcao-Tang on COX-2 expression in Acute and Resolution Phases of Carrageenin-Induced Pleurisy in Rats. Trop J Pharm Res 2013; 12(5):727-733 doi: 10.4314/tjpr.v12i5.10

© 2013 The authors.
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Abstract

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-Δ^{12, 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, 13.3 and 40 g/kg SGT also significantly decreased exudate volume by 36 (p < 0.05) and 55 % (p < 0.01), as well as total cell number by 31 (p < 0.05) and 43 % (p < 0.01), but markedly increased 15d-PGJ₂ production by 26 (p < 0.05) and 51 % (p < 0.01), as well as COX-2 protein expression by 50 (p < 0.01) and 100 % (p < 0.01) compared with control group.

Conclusion: The findings suggest that SGT has dual regulating effect in acute and resolution phases of inflammation, involving inhibiting acute inflammation through down-regulation of pro-inflammatory mediators, and promoting inflammatory resolution through up-regulation of pro-resolution mediators.

Keywords: Shaoyao-Gangcao-Tang, Cyclooxygenase-2, Prostaglandin E2, 15-Deoxy-[6;12, 14-PGJ2, Inflammation