[Study on effect of total coumarins from Urtica dentata on dextran sulfate sodium-induced colitis in mice].

OBJECTIVE: To study the effect of total coumarins (TC) from Urtica dentata on dextran sulfate sodium (DSS)-induced colitis in mice. METHOD: The colitis model was established by administering DSS. Having been treated with TC, their body weight was determined. Concentrations of IL-6, IL-10, TGF-beta1 and IFN-gamma were monitored by ELISA. Colon samples were collected for the histopathological examination. Western blot was used to detect TLR4 and NF-kappaB protein expression in colonic tissues. RESULT: TCs from U. dentata effectively controlled the body weight loss of mice with colitis, down-regulated the concentration of IL-6 and IFN-gamma and increased the suppressive cytokines IL-10 and TGF-beta1 in the serum. Additionally, TC alleviated the mucosal damage and decreased the expressions of TLR4 and NF-kappaB in colonic tissues. CONCLUSION: TCs from U. dentata shows the anti-inflammatory effect on colitis in mice by reducing the expressions of TLR4 and NF-kappaB in colonic tissues and regulating pro-and anti-inflammatory cytokines.

Intramuscular delivery of a naked DNA plasmid encoding proinsulin and pancreatic regenerating III protein ameliorates type 1 diabetes mellitus.

Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by inflammation of pancreatic islets and destruction of ß cells. Up to now, there is still no cure for this devastating disease and alternative approach should be developed. To explore a novel gene therapy strategy combining immunotherapy and ß cell regeneration, we constructed a non-viral plasmid encoding proinsulin (PI) and pancreatic regenerating (Reg) III protein (pReg/PI). Therapeutic potentials of this plasmid for T1DM were investigated. Intramuscular delivery of pReg/PI resulted in a significant reduction in hyperglycemia and diabetes incidence, with an increased insulin contents in the serum of T1DM mice model induced by STZ. Treatment with pReg/PI also restored the balance of Th1/Th2 cytokines and expanded CD4(+)CD25(+)Foxp3(+) T regulatory cells, which may attribute to the establishment of self-immune tolerance. Additionally, in comparison to the mice treated with empty vector pBudCE4.1 (pBud), attenuated insulitis and apoptosis achieved by inhibiting activation of NF-κB in the pancreas of pReg/PI treated mice were observed. In summary, these results indicate that intramuscular delivery of pReg/PI distinctly ameliorated STZ-induced T1DM by reconstructing the immunological self-tolerance and promoting the regeneration of ß cells, which might be served as a promising candidate for the gene therapy of T1DM.

Immunosuppressive constituents from Urtica dentata Hand.

A novel biscoumarin, 6,6',7,7'-tetramethoxyl-8,8'-biscoumarin (1), was isolated from the ethyl acetate extract of Urtica dentata Hand, together with five known compounds named as 7,7'-dihydroxy-6,6'-dimethoxy-8,8'-biscoumarin (2), 7,7'-dimethoxy-6,6'-biscoumarin (3), scoparone (4), vanillic acid (5), and daucosterol (6). Structures of the isolated compounds were elucidated on the basis of spectroscopic analysis including 2D NMR experiments. Compounds 1 and 2 were confirmed to be a rare carbon-carbon linked symmetrical biscoumarin. Compounds 1-4, especially 1 (IC(50) = 8.18 x 10(- 5) mol/l), showed potent immunosuppressive activities as determined by the Cell Counting Kit-8 assay for lymphocyte proliferation. Also, in the FACS analysis, 1 (IC(50) = 5.19 x 10(- 4) mol/l) promoted the differentiation of CD4(+)CD25(+)Foxp3(+) T regulatory cells distinctly compared to the normal control. Thus, 1 possessed specific immunosuppressive property by eliciting T regulatory cells, which may provide a potential treatment strategy for autoimmune diseases.

[Recombination of RegIII-proinsulin-pBudCE4.1 plasmid and its therapeutic effect on STZ-induced type 1 diabetes mellitus].

The aim of this study is to investigate the therapeutic effect of RegIII-proinsulin-pBudCE4.1 plasmid on streptozotocin (STZ)-induced type 1 diabetes mellitus and its underlying mechanisms. The model of type 1 diabetes mellitus was established by intraperitoneal injections of STZ (40 mg kg(-1)) to Balb/c mice for five consecutive days. Then, ten type 1 diabetic mice were intramuscularly injected with 100 microg RegIII-proinsulin-pBudCE4.1 plasmid for 4 weeks (one time/week) and the blood glucose levels were monitored every week; whereas another ten diabetic mice served as negative control group were injected with pBudCE4.1 vector at the same dose. Normal control and model control mice were treated with normal saline at identical volume under the same way. Western blotting, MTT assay, ELISA, HE staining and Tunel assay were applied to explore the underlying mechanisms. Results showed that RegIII-proinsulin-pBudCE4.1 plasmid ameliorated the hyperglycemia symptoms in diabetic mouse remarkably. It induced an immunological tolerance state in type 1 diabetic mice by inhibiting the proliferation of splenic lymphocytes and recovering Th1/Th2 balance evidenced by MTT and ELISA analysis. Furthermore, it elevated insulin concentration in the serum of type 1 diabetic mice and promoted the regeneration of beta cells supported by the results of HE staining and Tunel assay. In conclusion, RegIII-proinsulin-pBudCE4.1 plasmid possesses powerful anti-diabetic ability, which may be involved in the inducing of immunological tolerance and enhancing beta cells recovery.

Immunosuppressive effects of an ethyl acetate extract from Urtica dentata Hand on skin allograft rejection.

AIM OF THE STUDY: To investigate the immunosuppressive effects of HPLC qualitied ethyl acetate extract (EAE) from Urtica dentate Hand on skin allograft rejection in a murine model. MATERIALS AND METHODS: Allo-skin transplantation model was established by placing skin allograft of C57BL/6 mice in the wound bed which was on the back of Balb/c mice. We used FACS to study the effects of EAE on dendritic cells (DCs) maturation and CD4(+)CD25(+)T regulatory cells (Tregs) differentiation. We also studied spleen lymphocyte proliferation and T-bet gene expression in DCs. Concentration of Th1/Th2 cytokines was monitored as markers of Th1/Th2 responses by ELISA. RESULTS: A significant prolongation of skin allografts survival was observed as a dose-dependent manner in the animals treated with EAE. By FACS, we found that treatment with EAE (200 mg kg(-1)) resulted in an immature statement of DCs and stimulated the differentiation of CD4(+)CD25(+)Tregs. Additionally, the expression of T-bet gene and the proliferation of spleen lymphocytes were efficiently abated in EAE treated mice. Comparing to the model control, EAE-treated recipients showed a significant down-regulation (P<0.01) of Th1 cytokines (IL-2, IFN-gamma) and an obviously increase (P<0.01) of Th2 cytokine (IL-10) in the serum, which presented in a dose-related way. CONCLUSIONS: The anti-allograft rejection effect of EAE by enhancing CD4(+)CD25(+)Tregs differentiation and sustaining DCs immaturation makes EAE to be a possible choice for treating autoimmune diseases in a way of inducing a stable immunological tolerance state.