Effect And Mechanism Of Chlorogenic Acid In Mice With Allergic Rhinitis

Allergic rhinitis(AR), which is a type of inflammatory disease of upper airway, is characterized by antigen-specific Ig E production and inflammatory cell infiltration.Symptoms of AR include sneezing, itching and respiratory obstruction, seriously, and also involve very severe eye and ear symptoms in clinic. Over 10% of the population in China suffers from allergic rhinitis, which creates societal burdens such as medical expenses and loss of productivity.Chlorogenic acid, which widely present in honeysuckle family. Lots of data addresses were shown to exert anti-inflammatory, anti-bacterial, anti-tumor. Levels of cholesterol in serum and liver tissues were decreased and cardiovascular were protected. However, the effect of Chlorogenic acid on the AR was not elucidated.The aim of our researches was to study the protective effect of Chlorogenic acid in ovalbumin(OVA)induced AR. Firstly, The models of AR mice were sensitized on every other day by intraperitoneal(i.p.) injection of 50μg OVA emulsified in 5mg aluminum hydroxide in a total volume of 0.2ml PBS and intranasal(i.n.) challenge with 5% or 10% OVA for 10 d,Based on the change of behavior, the weight of nosal draingage and the contents of Ig E and histamine in serum protein to evaluat which is the optimum concentration of intranasal(i.n.)challenge with OVA. Secondly, the AR model was developed by intraperitoneal injection of adjuvant suspension on every other day for 7 times. Adjuvant suspension include 50μg of OVA and 2mg of Al(OH)3, which were combined in 2ml of normal saline(NS). Then, the mice received a nasal drip of 10% OVA daily for 10 days, and in normal control were dripped NS. After administration with 50mg/kg, 100mg/kg and 200 mg/kg of Chlorogenic acid for30 min, the mice were attacked locally for 10 days. We observed behavior analysis, evaluated the weight of nosal draingage, related the index of thymus and spleen, determined the effect of Chlorogenic acid on the contents of cytokines, Ig E and histamine by ELISA in AR mice and analyzed the m RNA expression of inflammatory cytokines(IL-4, IL-5, IL-10, IFN-γ) in the nasal mucosa tissues samples by RT-PCR. Explore that there is protective effect ofChlorogenic acid and its related mechanism.Methods:1. OVA induced AR model in mice(1) Assessment of behavior changes, record the number of sneezing and the number of rubbing nasal for 10 min.(2) Assessment of the weight of nosal draingage.(3) Assessment of the contents of Ig E and histamine in serum protein.2. Effect of Chlorogenic acid in OVA induced AR(1) Assessment of behavior changes, record the number of sneezing and the number of rubbing nasal for 10 min.(2) Assessment of the weight of nosal draingage.(3) Assessment of the index of thymus and spleen.(4) Assessment of the contents of cytokines, IgE and histamine by ELISA.(5) Assessment of the m RNA expression of inflammatory cytokines(IL-4, IL-5, IL-10,IFN-γ) in the nasal mucosa tissues samples by RT-PCR.Results:1. OVA induced AR model in mice(1) The the number of sneezing and the number of rubbing nasal for 10 min, the weight of nosal draingage, preliminary showed that using 10% OVA induced AR seems more appropriate(P<0.001).(2) Compared with the normal group, the content of histamine and Ig E in serum with10% OVA model group mice significantly increase statistically difference(p<0.001). 5%OVA model group elevated serum histamine content in mice, statistically significant(p<0.05), but Ig E in serum of mice with high levels of trends, no statistically significant(p>0.05). Prove that the optimal concentration is 10% OVA in this study.2. Effect of Chlorogenic acid in OVA induced AR(1) Compared with the model group, Chlorogenic acid(50mg/kg, 100mg/kg and 200mg/kg) decreased the number of sneezing and the number of rubbing nasal in 10 min induced by OVA(p<0.05).(2) Compared with the model group, Chlorogenic acid(50mg/kg, 100mg/kg and 200mg/kg) can significantly decreased the weight of nosal draingage induced by OVA. The results showed a concentration-response relationship(p<0.05).(3) Compared with the model group, Chlorogenic acid(50mg/kg, 100mg/kg and 200mg/kg) not only decreased the index of spleen, but also increased the index of thymus(p<0.05).(4) Compared with the model group, Chlorogenic acid(50mg/kg, 100mg/kg and 200mg/kg) significantly improved the content of IL-4 and IFN-γ in nasal lavage fluid in AR mice(p<0.05).(5) Compared with the model group, Chlorogenic acid(50mg/kg, 100mg/kg and 200mg/kg) significantly decreased the content of histamine and Ig E, the level of cytokine in serum in AR mice(p<0.05).(6) Compared with the model group, Chlorogenic acid(50mg/kg, 100mg/kg and 200mg/kg) significantly up-regulation of IFN-γ expressions and down-regulation of IL-4, IL-5,IL-10 expressions(p<0.05).Conclusion:(1) Use 10% OVA induced AR symptoms associated with acute period the optimal concentration is 10% in this study.(2) Chlorogenic acid decreased the number of nose-scratching events in 10 min, the weight of nosal draingage, the index of spleen, the content of IL-4 in nasal lavage fluid(NLF)and the contents of cytokines, Ig E and histamine in serum; while increased the index of thymus, the content of IFN-γ in NLF, the contents of IFN-γ in serum and the rate of IFN-γ/IL-4; The data showed a statistically significant up-regulation of IFN-γ m RNA expressions and down-regulation of IL-4m RNA, IL-5m RNA, IL-10 m RNA expressions after adiminstration of Chlorogenic acid.