[Research progress of root exudates collection technology]. / æ ¹ç³»åˆ†æ³Œç‰©æ”¶é›†æŠ€æœ¯ç ”ç©¶è¿›å±•.

Root exudates play an important role in mediating the exchange of substrates, energy and information within the rhizosphere in terrestrial ecosystems. Constructing accurate and applicable sampling system of root exudates to precisely collect the characters including the component and concentration of root exudates and their responses to changing environments are a critical link and prerequisite to understand ecological processes and information exchanges across the root-soil interface. While both traditional and novel techniques for collecting root exudates aim to explore the diversity and concentration of root exudates, current exudate-collection methods could hardly avoid the damage of root system, the adsorption and release of root exudates by soil particles, and distur-bance from microbial metabolism, largely because plant roots are highly associated with the surrounding substrates and environments supporting their growth. Therefore, all root exudate collection methods have their own merits and shortcomings. We systematically reviewed the widely-used traditional and novel root exudates collection techniques and compared their advantages and disadvantages. Furthermore, considering the significance and authenticity of field study on the rhizosphere ecological processes in forest ecosystems, we proposed three frontier research directions regarding the construction of techniques for collecting root exudates in forest ecosystems according to the limits of current studies, aiming to provide foundation for related studies in the future.

Therapeutic effect of a hydroxynaphthoquinone fraction on dextran sulfate sodium-induced ulcerative colitis.

AIM: To evaluate the therapeutic effect of hydroxynaphthoquinone mixture (HM) on dextran sulfate sodium (DSS)-induced colitis and explore the underlying mechanisms. METHODS: BALB/c mice received 3.5% DSS for 6 d to induce ulcerative colitis. Groups of mice were orally administered HM 3.5, 7 and 14 mg/kg and mesalazine 200 mg/kg per day for 7 d. During the experiment, clinical signs and body weight, stool consistency and visible fecal blood were monitored and recorded daily. A disease activity index score was calculated for each animal. At the conclusion of the experiment, the colonic histopathological lesions were evaluated. Myeloperoxidase (MPO) activity and tumor necrosis factor-α (TNF-α) levels were determined. Protein expression levels of TNF-α, nuclear factor-κB (NF-κB) p65, inhibitor of κB (IκB) and phosphorylation of IκB (p-IκB) were analyzed by Western blot analysis. RESULTS: Administration of 3.5% DSS for 6 d successfully induced acute colitis associated with soft stool, diarrhea, rectal bleeding, and colon shortening, as well as a loss of body weight. Administration of HM effectively attenuated the severity of colonic mucosa injury. For histopathological analysis, HM treatment improved histological alterations and lowered pathological scores compared with the DSS only group. This manifested as a reduction in the extent of colon injury and inflammatory cell infiltration, as well as the degree of mucosal destruction. In addition, HM at doses of 7 and 14 mg/kg significantly decreased MPO activity in colonic tissue (0.98 ± 0.22 U/g vs 1.32 ± 0.24 U/g, 0.89 ± 0.37 U/g vs 1.32 ± 0.24 U/g tissue, P < 0.05) and serum TNF-α levels (68.78 ± 7.34 ng/L vs 88.98 ± 17.79 ng/L, 64.13 ± 14.13 ng/L vs 88.98 ± 17.79 ng/L, P < 0.05). Furthermore, HM down-regulated the expression of TNF-α, NF-κB p65 and p-IκBα in colonic tissue while up-regulating IκBα protein expression. These results suggest that the significant anti-inflammatory effect of HM may be attributable to its inhibition of TNF-α production and NF-κB activation. CONCLUSION: HM had a favorable therapeutic effect on DSS-induced ulcerative colitis, supporting its further development and clinical application in inflammatory bowel disease.

Effectiveness of a hydroxynaphthoquinone fraction from Arnebia euchroma in rats with experimental colitis.

AIM: To evaluate the potential effectiveness of hydroxynaphthoquinone mixture (HM) in rats with 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. METHODS: Colitis was induced by intracolonic administration of TNBS (80 mg/kg, dissolved in 50% ethanol). Rats were treated daily for 7 d with HM (2.5, 5, 10 mg/kg) and mesalazine 100 mg/kg 24 h after TNBS instillation. Disease progression was monitored daily by observation of clinical signs and body weight change. At the end of the experiment, macroscopic and histopathologic lesions of rats were scored, and myeloperoxidase (MPO) activity was determined. We also determined inflammatory cytokine tumor necrosis factor (TNF)-α level by ELISA, Western blotting and immunochemistry to explore the potential mechanisms of HM. RESULTS: After intracolonic instillation of TNBS, animals developed colitis associated with soft stool, diarrhea and marked colonic destruction. Administration of HM significantly attenuated clinical and histopathologic severity of TNBS-induced colitis in a dose-dependent manner. It abrogated body weight loss, diarrhea and inflammation, decreased macroscopic damage score, and improved histological signs, with a significant reduction of inflammatory infiltration, ulcer size and the severity of goblet cell depletion (all P < 0.05 vs TNBS alone group). HM could reduce MPO activity. In addition, it also decreased serum TNF-α level and down-regulated TNF-α expression in colonic tissue. This reduction was statistically significant when the dose of HM was 10 mg/kg (P < 0.05 vs TNBS alone group), and the effect was comparable to that of mesalazine and showed no apparent adverse effect. The underlying mechanism may be associated with TNF-α inhibition. CONCLUSION: These findings suggest that HM possesses favourable therapeutic action in TNBS-induced colitis, which provides direct pharmacological evidence for its clinical application.

[Effect of ecdysterone on the proliferation of human umbilical cord mesenchymal stem cells in vitro].

OBJECTIVE: To investigate the effect of ecdysterone on the proliferation of human umbilical cord mesenchymal stem cells (hUCMSCs) in vitro. METHODS: hUCMSCs isolated by enzyme digestion from human umbilical cord tissues were cultured and identified for the surface antigens using fluorescence-activated cell sorting (FACS). The cells were treated with ecdysterone at the concentrations of 0, 25, 50, 100, 150, and 200 µg/ml, and the changes in the cell proliferation were detected using MTT assay. RESULTS: The third-passage hUCMSCs were positive for CD29 and CD105 and negative for CD34 and CD45 as shown by flow cytometry. Treatment with ecdysterone resulted in significantly increased cell proliferation as compared to the control cells (P<0.05), but no significant differences were found in cells treated with 100, 150, and 200 µg/ml ecdysterone (P>0.05). The growth curves of the cells also demonstrated the definite effect of ecdysterone in promoting the proliferation of hUCMSCs. CONCLUSION: Ecdysterone can promote the proliferation of hUCMSCs in vitro with the optimal concentration of 100 µg/ml, suggesting its potential value in the enrichment of mesenchymal stem cells.

[Effect of ecdysterone on the proliferation of human mesenchymal stem cells in vitro].

OBJECTIVE: To investigate the effect of ecdysterone (EDS) on the proliferation of human bone marrow mesenchymal stem cells (hMSCs) in vitro. METHODS: hMSCs were isolated from human bone marrow cell suspension by density gradient centrifugation. The expression of integrins CD44, CD105, CD34 and CD29 were examined by immunocytochemical method. EDS at 10, 25, 50 or 100 microg/ml were added in hMSC culture system, using the routine culture medium for hMSCs as control. The cell viability were analyzed by MTT assay and the cell cycle changes were examined by flow cytometry. RESULTS: The optical density (OD) differed significant between the EDS treatment groups and the control group (P<0.01), and 25 microg/ml EDS group showed the highest OD value (P<0.01) without significant differences among 10, 50 and 100 microg/ml EDS groups (P>0.05). Flow cytometry showed that treatment of the cells with 25 microg/ml EDS significantly increased the cell percentages in S and G(2)M phases and the proliferation index (PI) of the cells as compared with the control group. CONCLUSION: Within a given concentration range, EDS can promote the proliferation of hMSCs in vitro, and this effect can be the most obvious at the concentration of 25 microg/ml. The effect of EDS in promoting the proliferation of hMSCs does not positively correlate to EDS concentration administered.