OBJECTIVETo explore the pathological mechanisms of Guizhi Decoction () syndrome and the therapeutic molecular mechanisms of the Guizhi Decoction, Mahuang Decoction (), Sangju Decoction ( ) and Yinqiao Powder (), as well as the potentially biological basis that Guizhi Decoction is most effective only for the patients with Guizhi Decoction syndrome in clinical practice.

METHODSWe first got serum samples from the patients suffering from both upper respiratory tract infection and Guizhi Decoction syndrome identified by the doctors of Chinese medicine (CM) in the clinic. Four formulas with therapeutic actions of pungent warmth or pungent coolness for superficial syndromes were chosen and four kinds of rat serum samples each containing one of the above-mentioned herbal formulas were collected, then the effects of Guizhi Decoction syndromes' patient serum as well as the effects of sera containing the formulas after being stimulated by the patient serum samples on both the mRNA expression of certain toll-like receptor (TLR) subtypes and the release of some inflammatory cytokines in RAW264.7 cells were tested and analyzed in vitro.

RESULTSThe expression of TLR-3, TLR-4 and TLR-9 mRNA among the 9 tested TLR subforms were up-regulated in the macrophages stimulated by the sera from untreated upper respiratory infection patients with the Guizhi Decoction syndrome (symptomcomplex). The products such as interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α and interferon (IFN)-β from stimulated macrophages through TLR signaling pathways were also increased correspondingly. Interestingly, the changes induced by the Guizhi Decoction syndrome patients' sera were masked significantly after the macrophages were incubated with the sera from donors treated with Guizhi Decoction. Similarly, the three other exterior-releasing formulas were all effective in reversing the up-regulated changes of certain TLR subforms to different degrees, but both the number of targeted TLRs and efficacy of them seemed to be inferior to that of Guizhi Decoction.

CONCLUSIONEvidence from these experiments might contribute to the scientific explanation of both the pharmacological mechanisms of Guizhi Decoction and also the CM theory that Guizhi Decoction is specifically prescribed for the treatment of Guizhi Decoction syndrome (The gearing formula to the symptom-complex).