Antiasthmatic Effects Of Certain Bushen And Yiqi Herb In A Rat Model Of Asthma

ObjectiveTo investigate the effects of Bushen and Yiqi Chinese herb including epimedium, psoralea fruits, astragalus membranaceus and pseudostellariae on asthma in a rat model of asthma, and explore the mechanism of Bushen and Yiqi Chinese herbs on airway inflammation, of which their effects on the immunity systerm and HPA axis including both pro-inflammation and anti-inflammation effects will be mostly concerned. Moreover, effects of these herbs on airway hyperreactivity and remodeling were to be further investigated.Methods1.150SD rats were randomly divided into15groups as follows:a control group (10rats), an OVA induced model group (10rats), a DEX (0.5mg/kg) treatment group (10rats), three epimedium (Epi)(2.5,5.0, or10.0g/kg) treatment groups (10rats per group), three psoralea fruits (PF)(2.5,5.0, or10.0g/kg) treatment groups (10rats per group), three astragalus membranaceus (AM)(2.5,5.0, or10.0g/kg) treatment groups (10rats per group), and three pseudostellariae (PS) treatment groups (10rats per group).2. To establish asthma model by intraperitineal injecting sensitized liquid and breathing atomizated egg albumin consecutively.3. AHR was evaluated by a Buxco’s modular and invasive system.4. lung tissue were stained with hematoxylin-eosin (H&E), periodic acid Schiff (PAS) and Masson’s Trichrome to evaluate the severity of inflammatory cell infiltration, airway mucus expression, and collagen deposition in lung tissue.5. Interleukin (INF-y, IL-4, IL-5, IL-6, IL-13, TNF-α and TGF-β1) levels in the BALF supernatant and serum were analyzed by ELISA.6. Cells from the BALF were analyzed for CD4+CD25+Foxp3+expression by Flow cytometric analysis. 7. ACTH and CORT were detected by ELISA.8. CRHmRNA in hypothalamus were detected with the method of real time PCR.9. Bax、Bcl-2、Caspase-3、Fas、FasL in hypothalamus were detected by Western blotting.10. Apoptosis in tissues of hypothalamus, pituitary, and adrenal gland were detected by TUNEL staining.Results1. Compared with the normal group, the airway resistance (RL) was significantly increased, and lung dynamic compliance (Cdyn) was remarkablly reduced (P<0.05). Compared with model group, dexamethasone and certain concentrations of Epi, PF, AM, but not PS, significantly reduced RL, while improved Cdyn (P<0.05).2. H&E staining showed that there were significant infiltration of inflammatory cells into the peribronchiolar and perivascular connective tissues in model group compared to normal group. Dexamethasone significantly reduced the airway inflammation, while Epi and AM also significantly inhibited airway inflammation both at the dose of5.0and10.0g/kg, as well as PF at the dose of10.0g/kg (P<0.05). However, the PF at the dose of2.5and5.0g/kg, and PS at the dose of2.5,5.0and10.0g/kg exhibited no significant effects on airway inflammation (P>0.05).3. PAS staining showed that there were significant mucus production in model group compared to normal group (P<0.05). Dexamethasone significantly reduced the mucus production, while Epi and AM at the dose of5.0and10.0g/kg, and PF at the dose of10.0g/kg significantly reduced the mucus production (P<0.05). However, the PF at the dose of2.5and5.0g/kg, and PS at the dose of2.5,5.0and10.0g/kg have no significant effects on mucus production (P>0.05).4. Masson’s Trichrome staining showed that the model group exhibited a marked increasement of peribronchial collagen deposition compared to the normal group (P <0.05). Dexamethasone significantly inhibited the collagen deposition, while Epi and AM at the dose of2.5,5.0and10.0g/kg significantly reduced the collagen deposition (P<0.05). However, the PF and PS at the dose of2.5,5.0and10.0g/kg have no significant effects on collagen deposition (P>0.05).5. OVA-exposed rats presented significantly elevated levels of IL-4, IL-5, IL-13, TGF-β1,TNF-a, as well as a reduced INF-y level in the BALF in comparison to normal rats (P<0.05). Dexamethasone significantly inhibited up-regulation of IL-4, IL-5, IL-13, TGF-β1. Epi obviously and dose-dependently inhibited the IL-4, IL-5, and IL-13in BALF (P<0.05). PF at the dose of10.0g/kg significantly reduced IL-4and IL-13in BALF (P<0.05). AM dose-dependently inhibited the IL-4, IL-5, IL-13and TGF-β1in BALF, as well as increase the level of INF-γ(P<0.05). However, PS at the dose of2.5,5.0and10.0g/kg have no significant effects on these cytokines (P>0.05).6. OVA-exposed rats presented significantly reduced levels of INF-y, as well as elevated levels of IL-10(P<0.05), while no significant changes of IL-4, IL-5, IL-6, IL-13, TNF-a, TGF-β1in serum in comparison to normal rats (P>0.05). Dexamethasone significantly inhibited up-regulation of TNF-a. Compared to the model group, certain concentrations of Epi obviously increased INF-y in serum, and reduced levels of TGF-β1and TNF-a (P<0.05). Certain concentrations of PF significantly reduced TGF-β1(P<0.05). Certain concentrations of AM obviously increased level of INF-y and reduced of TGF-β1(P<0.05). Certain concentrations of PS significantly reduced TGF-β1level in serum (P<0.05).7. Compared to the normal group, CD4+CD25+Foxp3+Treg cells had a tendency to be reduced in the model group, but without statistical significance (P>0.05). However, Dexamethasone and AM at the dose of5.0and10.0g/kg significantly enhanced CD4+CD25+Foxp3+Treg cells (P<0.05), while Epi, PF and PS at the dose of2.5,5.0and10.0g/kg had no effect on the CD4+CD25+Foxp3+Treg cells in BALF.8. OVA-exposed rats did not present significant difference of ACTH and CORT in serum compared to the normal rats (P>0.05). However, ACTH and CORT were not significantly changed in groups of Dexamethasone, Epi, PF, AM and PS at the dose of2.5,5.0and10.0g/kg(P>0.05).9. OVA-exposed rats exhibited significantly reduced CRHmRNA in hypothalamus compared to the normal rats (P<0.05). Dexamethasone had a tendency to reduce CRHmRNA in hypothalamus, but without statistical significance (P>0.05). Epi at the dose of10.0g/kg had a tendency to increase CRHmRNA in hypothalamus, but without statistical significance (P>0.05). CRHmRNA in other groups were not significantly changed compared to the model group (P>0.05).10. Compared to the normal group, the expression of Bax and Cleaved Caspase-3, which were the key molecules of apoptotic signaling pathway, were significantly increased (P<0.05), and the ratio of expression of Bcl-2to Bax was reduced (P <0.05). Certain concentrations of Epi, PF, AM and PS reduced the expression of Fas or Fas-L, but do not inhibited the expression of Bax, Fas-L and Cleaved Caspase-3, neither could increased the expression of Bcl-2or the ratio of Bcl-2to Bax (P>0.05).11. Apoptotic indexes in tissues of hypothalamus, hypophysis and adrenal gland were not statistically different between the normal and the model group (P>0.05). Dexamethasone significantly increased the apoptotic indexes in tissues of hypothalamus and adrenal gland (P<0.05). However, Epi, PF, AM and PS do not significantly changed the apoptotic indexes (P>0.05).Conclusion1. Bushen herb Epi significantly alleviated airway inflammation, airway hyperreactivity and remodeling in a rat model of asthma. Its inhibition on airway inflammation was associated with the inhibition of inflammatory cytokines in BALF and might also with the improvement of HPA axis function. Bushen herb PF also exhibited some antiasthmatic effects of airway inflammation and hyperreactivity, which was associated with the inhibition of IL-4and IL-13in BALF. However, compared between the Bushen herbs, the antiasthmatic effects of Epi was better than that of PF.2. Yiqi herb AM significantly alleviated airway inflammation, airway hyperreactivity and remodeling in a rat model of asthma. Its inhibition on airway inflammation was associated with the inhibition of inflammatory cytokines in BALF and enhancement of T regulatory cells. Yiqi herb PS exhibited no significant effects on airway inflammation, airway hyperreactivity and remodeling. As a result, the antiasthmatic effects of AM was better than that of PS.3. Bushen herb Epi and Yiqi herb AM both can significantly alleviated airway hyperresponsiveness and inflammation. Epi may also can improve the HPA axis function since it can increase the CRHmRNA, while AM can enhance the T regulatory cells. On the whole, Epi exhibited effects on the regulation of both immunity and HPA axis, while AM exhibited better effects on the regulation of immunity.