| Fever, incidental in many diseases, is a symptom of pathological body temperature increase because the body temperature set point is increased by pyrogen. After the body is stimulated by exogenous pyrogen, the content of endogenous pyrogen in the body is increased to result in the body temperature increase through acting on body temperature regulation center in the hypothalamus. High fever or prolonged fever can cause damage to the body. There are many drugs to treat fever in clinical practice, but a lot of drugs have side effect on the gastrointestinal mucosa, liver, and kidney. In order to find antipyretic drugs with high safety, traditional Chinese medicine come into foucus. Baihu Decoction is the classic recipe of heat-clearing effect attending YANG MING meridian syndrome and Qi Fen heat syndrome. Modified Baihu Decoction is consists of Baihu Decoction minus rice plus honeysuckle and forsythia altogether. Honeysuckle and forsythia have the effect of heat-clearing, detoxification, subsiding swelling and dispersing stasis. In this experiment, research the antipyretic effect of modified Baihu Decoction on yeast-induced fever, and its mechanism of action were explored.Firstly, the effect of different yeast concentration on rats was studied to establish the pyrexia rat model by subcutaneous injection of 5%, 10%, 15% yeast suspension. The results showed that the temperature of rats in the three groups all significantly increased after injecting the yeast suspension and the 10% of yeast concentration as heat stimuli was best.The pyrexia model was established by injecting 10% of yeast concentration subcutaneously to rats. Firstly, Baihu Decoction were given to observe its effect, then high, medium and low dose modified Baihu Decoction and aspirin(ASP) were given through intragastric administration. The rectal temperature was recorded every one hour, then rats were anesthetized and dissected, the change of morphology in the lung tissue and liver tissue were observed, and histopathologic slides were made to observe the pathological changes. The results showed that after subcutaneously injecting dry yeast suspension, the temperature of rats in the model group was significantly increased compared with the normal group, indicating that the pyrexia rat model was established successfully. Baihu Decoction antipyretic effect was not obvious, and the time of duration was short. Modified Baihu Decoction of high, medium and low dose group all have antipyretic effect. Combined with pathological changes in the liver and lung, the antipyretic effect of high-dose group was better.Ten percent of yeast concentration was choosed to construct pyrexia rat model and high doses of modified Baihu Decoction was given intragastric administration at 0 h and 4 h after pyrexia induction. By using ELISA, electrolyte measure instrument and RT-PCR, the antipyretic mechanism was studied. The concentration of TNF-α, IL-1β, IL-6, IL-10, Na+/Ca2+, PGE2, c AMP in serum and the concentration of PGE2, c AMP in the hypothalamus were examined, and the m RNA expression levels of TNF-α, IL-1β, IL-6, IL-10, COX-2 in the hypothalamus were detected. The results showed that modified Baihu Decoction could significantly inhibit the production of TNF-α, IL-1β, IL-6, Na+/Ca2 +, c AMP in the serum, but had no significant effect on the PGE2 in serum, and c AMP in hypothalamus. Modified Baihu Decoction could inhibit the m RNA expression levels of TNF-α, IL-1β, IL-6, COX-2 in hypothalamus, but had no significant effect on IL-10 m RNA expression.In summary, modified Baihu Decoction can significantly inhibit the yeast-induced fever through reducing endogenous pyrogen and central pyrogenic medium. Our study could provide a new experimental basis for traditional Chinese medicine to treat fever. |
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