[Immunoregulatory effect of artesunate on allergic contact dermatitis and its mechanism].

This study is to elucidate the immunoregulation mechanisms of artesunate (AST) on allergic contact dermatitis (ACD). Pharmacodynamics analyses, HE staining, semi-quantitative RT-PCR and Western blotting were used to explore the effects of AST on the related cytokines, transcription factor and signaling molecule of ACD respectively. The results indicated that topical administration of AST not only reduced the increase of ear swelling, spleen index and inflammatory cells infiltration in ACD mice, but also inhibited remarkably the expression of IFN-gamma, T-bet and NF-kappaB p65. It's suggested that AST could exhibit suppressive effects on inflammatory response and immune function of ACD, which indicates the possibility of developing AST as a novel immunoregulatory agent in the treatment of ACD and other immune-related diseases.

Topical application of Pseudolaric acid B improve DNFB-induced contact hypersensitivity via regulating the balance of Th1/Th17/Treg cell subsets.

Pseudolaric acid B (PAB) is a novel diterpenoid, isolated from Pseudolarix kaempferi Gorden, which roots are widely used to treat inflammatory and microbial skin diseases for centuries, but the underlying mechanism remains elusive. To address the immunoregulatory mechanisms of PAB, we first investigated the effect of PAB in 2,4-dinitrofluorobenzene (DNFB)-induced contact hypersensitivity (CHS) mice. The expression of specific transcription factors for T-helper (Th)1, Th2, Th17 and regulatory T cells (Tregs) was determined by RT-PCR, and the capacities for PAB to modulate Th1/Th17/Treg cell subsets was furtherly analyzed by flow cytometric analysis, ELISA and Western blotting assay. The results showed that topical application of PAB could suppress ear swelling, block inflammatory infiltration, and interfere in Th1 response. Furthermore, PAB-treated CHS mice exhibited the impaired Th17 development and enhanced Tregs generation, associated with the up-regulation of peroxisome proliferator activated-receptor γ (PPAR γ) expression. These findings suggest that PAB exerts its immunoregulatory activity through regulating the balance of Th1/Th17/Treg cell subsets, which would provide a novel therapeutic application for PAB on CHS and other inflammatory-associated diseases.

Anti-inflammatory and immunomodulatory mechanisms of artemisinin on contact hypersensitivity.

Artemisinin (Art) is a sesquiterpene trioxane lactone from Artemisia annua L., which has been shown to affect immune responses. However, the underlying mechanism remains elusive. In this study, we examined the anti-inflammatory and immunomodulatory effects of Art in a mouse model of contact hypersensitivity (CHS), a T-cell-mediated cutaneous inflammatory reaction. The data showed that topical administration of Art could suppress CHS response and Con A-induced T cell proliferation effectively. Further experiments indicated that Art induced the generation of regulatory T cells (Tregs) and impaired the phosphorylation of AKT, associated with the up-regulation of p38 MAPK activation. Moreover, Art also exerted a strikingly inhibitory effect on IL-17 production, and diminished the level of IL-6 paralleled with an enhancement of TGF-ß, which effects were coupled with a significant reduction of STAT3 activation. These data reveal that Art could effectively block CHS response in mice by inducing the generation of Tregs and suppressing the development of Th17, indicating the potential of Art to be applied as an effective therapeutic agent for treating immune-related diseases.

Effects of osthole on apoptosis and TGF-beta1 of hypertrophic scar fibroblasts.

Osthole, 7-methoxy-8-[3-methylpent-2-enyl]coumarin (1), was extracted from a Chinese herb Cnidium monnieri (L.) Cuss. It showed immunity strengthening, anti-tumor, anti-hepatitis, and anti-osteoporosis activities in previous studies. Our goals are to study the effects of 1 on cell proliferation and TGF-beta of hypertrophic scar fibroblasts. Our results showed that 1 induced apoptosis and inhibited cell proliferation in hypertrophic scar fibroblasts. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that its IC(50) value toward hypertrophic scar fibroblasts was 15.5 +/- 2.2 micromol/l. Furthermore, the results of cell growth curve matched with the above results. Inducing apoptosis by 1 in hypertrophic scar fibroblasts was assessed by various morphological and biochemical characteristics, including cell shrinkage, chromatin condensation, membrane blebbing, formation of apoptotic bodies, and DNA ladder formation. A typical 'Sub-G(1) peak' was also checked through flow cytometry. We used immunohistochemistry to observe the expression of TGF-beta(1). Also, we found that 1 could obviously inhibit the expression of TGF-beta(1) of fibroblasts derived from hypertrophic scar compared with the control group (P < 0.05). These results suggest that 1 inhibits the growth of hypertrophic scar fibroblasts through apoptosis and decreases the expression of TGF-beta(1).

Effects of PLAB on apoptosis and Smad signal pathway of hypertrophic scar fibroblasts.

Pseudolaric acid-B (PLAB), a diterpene acid, was isolated from the root and trunk barks of Pseudolarix kaempferi. It has shown antifungal and anti-fertility effects and cytotoxic activities in previous studies. Our goals are to study the effects of PLAB on cell proliferation and Smad signal pathway of hypertrophic scar fibroblasts. Our results showed that PLAB induced apoptosis in hypertrophic scar fibroblasts and inhibited cell proliferation of hypertrophic scar fibroblast. MTT assay showed that its IC(50) value toward hypertrophic scar fibroblasts was 12.9+/-1.20 micromol/L. Furthermore, the results of cell growth curve matched with the above results. Inducing apoptosis by PLAB in hypertrophic scar fibroblast was assessed by various morphological and biochemical characteristics, including cell shrinkage, chromatin condensation, membrane blebbing, formation of apoptotic bodies, and DNA ladder formation. A typical "Sub-G1 peak" was also checked through flow cytometry. The Smad2 and Smad7 mRNA levels of 48-h PLAB treatment were determined by reverse transcription-polymerase chain reaction (RT-PCR) 48 h later. RT-PCR showed that Smad7 mRNA level increased and significant differences were observed between control group and experimental group (P<0.05); While there is no significant difference in Smad2 mRNA between the two groups. Our results showed that PLAB interfered with the microtubule dynamics of tubulin polymerisation and depolymerisation, which results in the inhibition of chromosomal segregation in mitosis and consequently the inhibition of cell division. These results suggest that PLAB inhibits hypertrophic scar fibroblast growth through apoptosis and Smad signal pathway.