ABSTRACT
OBJECTIVE To investigate the potential mechanism of procyanidin on rats with gingivitis by regulating phosphoinositide 3-kinase （PI3K）/protein kinase B （Akt）/vascular endothelial growth factor （VEGF） signaling pathway. METHODS The rat model of gingivitis was constructed by sewing the neck of the first maxillary molar with silk thread+applying maltose on the gum+feeding with 20% sucrose solution and soft food. Forth-eight model rats were randomly divided into model group， procyanidin group （160 mg/kg）， 740Y-P group （PI3K/Akt signaling pathway activator， 0.02 mg/kg）， and procyanidin+ 740Y-P group （procyanidin 160 mg/kg+740Y-P 0.02 mg/kg）， with 12 rats in each group； another 12 rats were selected as control group； each medication group was treated with corresponding drugs intragastrically or/and intraperitoneally， once a day， for 7 consecutive days. Twenty-four hours after the last administration， the gingival index of rats was measured； the levels of interleukin- 18 （IL-18）， inducible nitric oxide synthase （iNOS） and alkaline phosphatase （ALP） in gingival crevicular fluid， as well as the levels of superoxide dismutase （SOD）， catalase （CAT） and reactive oxygen species （ROS） in gingival tissues of rats were detected； the pathological changes in gingival tissues were observed； the expression levels of PI3K/Akt/VEGF signaling pathway- related proteins in gingival tissues of rats were detected. RESULTS Compared with control group， the gingival tissues of rats in the model group had severe pathological damage，which was manifested as local tissue expansion and congestion， new capillaries， degeneration and loss of collagen fibers and disorder of arrangement， and a large number of inflammatory cell infiltration in the gingival sulcus wall. The gingival index， the levels of IL-18， iNOS， ALP in gingival crevicular fluid， the level of ROS in gingival tissues， the phosphorylations of PI3K and Akt， as well as the protein expression of VEGF in gingival tissues were significantly increased； the levels of SOD and CAT in gingival tissues of rats in model group were significantly decreased （P＜0.05）. Compared with model group， the pathological damage to the gingival tissues of rats in procyanidin group was reduced， and all quantitative indicators were significantly improved （P＜0.05）； 740Y-P could reverse the improvement effect of procyanidin on various indicators （P＜0.05）. CONCLUSIONS Procyanidin may alleviate gingival tissue damage， and improve gingival inflammation and oxidative stress in rats with gingivitis by inhibiting PI3K/Akt/VEGF signaling pathway.
ABSTRACT
BACKGROUND:Intestinal fibrosis is a common complication in inflammatory bowel disease and leads to functional damage and intestinal obstruction. Intestinal fibrosis is mainly related to the imbalance of deposition and degradation of extracellular matrix components, such as collagens and fibronectins. Studies have found that mesenchymal stem cells secreted soluble bioactive substance such as extracellular vesicles via paracrine action, which exerted marked anti-fibrosis effect. OBJECTIVE: To investigate the effect of human placenta mesenchymal stem cells-derived extracellular vesicles on collagen deposition in mice with colitis. METHODS: Totally 24 BALB/c mice were randomly divided into sham operation group, model group and extracellular vesicles group, with 8 mice in each group. Except the sham operation group, the remaining mice of model group and extracellular vesicles group were treated with trinitro-benzene-sulfonic acid to induce intestinal fibrosis, once a day for 6 weeks. The mice in the extracellular vesicles group and model group were administered with extracellular vesicles and phosphate-buffered saline, respectively, at 3 weeks, once a day for 6 weeks. The therapeutic effect of extracellular vesicles was evaluated by disease active index score and the colon weight/length ratio at 1-7 weeks. Diseased intestinal segment was subjected to histological staining. Western blot assay and RT-PCR were used to measure fibrosis related indicators so as to evaluate the degree of intestinal fibrosis. RESULTS AND CONCLUSION: (1) Compared with the model group, disease active index score and the colon weight/length ratio were significantly reduced, and colonic pathology was significantly improved in the extracellular vesicles group. (2) Compared with the model group, collagen deposition in colon mucosa of mice was significantly reduced, and the expression of collagen I, collagen III and transforming growth factor-β1 decreased significantly in the extracellular vesicles group. (3) Compared with the model group, expression levels of matrix metalloproteinase 2 and matrix metalloproteinase 9 in mouse colon tissue were significantly increased, while the expression level of tissue inhibitor of metalloproteinase 1 was decreased in the extracellular vesicles group. (4) Results suggest that human placenta mesenchymal stem cells-derived extracellular vesicles can obviously improve the severity of colon injury and reduce the collagen deposition of intestinal mucosa in mice with enteritis.