The Anti-inflammatory Effects Of Triterpene Acids Of Loquat. Leaf And Its Mechanisms Of Therapeutic Actions On Chronic Bronchitis

Chronic bronchitis(CB) is a common and preventable disease that has implications for global health.It is a complicated pathophysiological process,including calcium overload,free radical production,metabolic abnormalities,and inflammatory reaction,etc.Regulation disorder of neuroendocrine-immuno-function is one of the important techniques for chronic bronchitis therapy.As a major effector of the innate immune system of the body,alveolar macrophage (AM) interact with other cells in airways and alveoli immediately after birth,resulting in generation of intracellular signaling cascades,leading to various effects or functions that make up the initial immune response in the lungs.Interaction of AM and lipopolysaccharides(LPS) causes a sequential activation production of both proand anti-inflammatory mediator in the lungs.Traditionally,the leaf of Eriobotrya japonica(Thunb.)Lindl has a long history of medicinal use in South-east Asia in a variety of inflammatory conditions especially CB therapy.According to our previous study,the triterpene acids extracted from Eriobotrya japonica(Thunb.)Lindl Leaf was the effective component and had therapy effect on chronic bronchitis.TAL could suppress the LPS-induced inflammatory response through inhibiting the production of NF-κB,TNF-α,IL-1,iNOS expression increase IL-10 expression from alveolar macrophage in CB rats,affect the oxide and anti-oxide balance so as to protect the lung from oxidative damage,decrease the inflammation media such as PGE₂ and LTB₄ production.The signal transduction of inflammation media in AM of CB remains unclear.The anti-inflammatory mechanisms of Triterpene Acids of Loquat.Leaf(TAL) in chronic bronchitis were studied by using the method in vivo and in vitro.Owing to the importance of AM in the processor of chronic bronchitis,effects of TAL on AM functions were investigated.Since Mitogen-activated protein kinases(MAPKs) are crucial for maintenance of cells in many signaling pathways operant in a variety of stress responses especially in inflammation process MAPK signal transduction pathway of inflammation media and cytokines production in AM of CB rats was studied.Furthermore the effect of TAL on the pathway was also investigated.The main contents are divided into some sections as follows:1.MAPK signal transdnction pathway of inflammation media and cytokines production in AM of CB ratsThe inhibitors of JNK,p38 or ERK MAPK suppressed IL-1 and TNF-αactivity and mRNA expression while JNK,p38 MAPK inhibitors suppressed TNF-αprotein expression.PGE₂ synthesis from AM of CB rats was suppressed by PD98059 and Curcumin.COX-2 mRNA and protein expression were partially downregulated by the JNK and ERK MAPK inhibitors Curcumin and PD98059.HO-1 mRNA was partially downregulated by the p38 MAPK inhibitor SB203580 while HO-1 protein secretion was notably suppressed by SB203580 and Curcumin.In summary,different MAPK signal transduction(JNK,p38 or ERK MAPK) participated into the inflammation media and cytokines production in AM of CB rats and MAPK signal transduction could modulate inflammation media expression through transduction post-transduction levels.2.MAPK signal transduction pathway in AM of CB rats and the effect of TAL on MAPK activation.Special inhibitors of PTK,PI3-K,Akt and PKC were used to detect correlated signal protein of MAPK before transcription in AM of CB rats.PKC,PI3K/Akt, phosphorylation were reduced after treatment with inhibitors of PTK.LY294002,the inhibitor of PI3K suppressed PI3K and Akt phosphorylation but increased p38 and JNK phosphorylation.ERK phosphorylation was decreased by Calphostin C,a inhibitor of PKC,while it had no effect of p38 and JNK phosphorylation.The LPS-induced MAPK signal pathway in AM of CB rats may be PTK-----PI3K/Akt------JNK/p38 or PTK-----PI3K-----PKC-----ERK.Further research investigated that phosphorylation of p38,JNK,ERK,PKC and Akt but not PI3K was decreased by TAL.TLR4 receptor expression in AM of CB rats was highly increased while TAL could not effect on its production.In summary,action of TAL on MAPK in AM may be happened on certain tache backward position of PI3K3.Effect of TAL on AM apoptosis of CB rats and its probable mechanismEffect of TAL on alveolar macrophage(AM) apoptosis and activity of chronic bronchitis(CB) rats was investigated.MTT method was used to detect the AM activity and the apoptosis rate of AM was observed by flow cytometry:FITC-Annexin V/PI double staining.To further investigate the underlying mechanism,expressions of Bax and Bcl-2 protein were examined.The number and activity of AM in CB rats was increased than that of normal group(P＜0.01).The apoptotic rate of AM in CB group was much lower than the control group[(13.93±3.34)%vs(5.37±1.38)%](P＜0.01). ERK inhibitor PD98059 induced the apoptosis of cultured AM while JNK inhibitor Curcumin reduced the apoptosis.TAL could decrease activity and increase apoptosis of AM in CB rats witch might be related to its therapy effect of CB.ERK and p38MAPK signal transduction participate in the apoptosis of AM.Further investigation showed that Bcl-2 protein expression and cytosolic calcium concentration was significantly increased while Bax evidently decreased in AM of CB rats.TAL could significantly decrease Bcl-2 expression and increase Bax protein expression,decrease cytosolic calcium concentration in AM of CB rats,which might be mechanism of its effect.