Conjugated linoleic acid improves glucose and lipid metabolism in diabetic mice / 南方医科大学学报

OBJECTIVE@#To analyze the effect of conjugated linoleic acid (CLA) on glucose and lipid metabolism in obese diabetic (db/db) mice.@*METHODS@#db/db mice were randomized for treatment with saline or CLA mixture administered intragastrically. The changes in body weight, dietary intake, water intake, oral glucose tolerance, triglyceride and total cholesterol were recorded after the treatments. HE staining and oil red O staining were used to assess liver pathologies and fatty acid content. The expression levels of PPARα, PPARγ, CD36, CHREBP and SREBP-1c were detected using real-time PCR and Western blotting. HepG2 cells were treated with CLA and linoleic acid and the expressions of PPARα, ACC, P-ACC, and CD36 were detected; the level of acetyl-CoA in the cell supernatant was detected using ELISA.@*RESULTS@#CLA treatment obviously reduced the dietary and water intake of db/db mice, effectively reduced the body weight and decreased serum triglyceride and cholesterol levels ( < 0.05). CLA significantly reduced fasting blood glucose, increased glucose tolerance, reduced the accumulation of lipid droplets in the liver and improved lipid metabolism in db/db mice. The mice showed significantly increased expression of PPARα ( < 0.05) and lowered CD36 expression ( < 0.001) in the liver after CLA treatment. Cellular experiments showed that CLA significantly up-regulated PPARα ( < 0.001) and P-ACC and decreased the expression of CD36 ( < 0.01). ELISA showed that acetyl-CoA was significantly up-regulated in the cells after CLA treatment ( < 0.01).@*CONCLUSIONS@#The mixture of two conjugated linoleic acid isomers can reduce fasting blood glucose, increase glucose tolerance and improve glycolipid metabolism in db/db mice by enhancing the expression of PPARα, increasing P-ACC and inhibiting CD36 expression.

Intragastric administration of interferon-α-transformed Bifidobacterium promotes lymphocyte proliferation and maturation in mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of intragastric administration of human interferon-α (hIFN-α)-transformed Bifidobacterium on immune functions of mice.</p><p><b>METHODS</b>The E.coli-Bifidobacterium shuttle expression vector containing hIFN-α gene was constructed and transformed into Bifidobacterium. The hIFN-α-transformed Bifidobacterium suspension (1010 /ml) was prepared after induction with 0.2% L-arabinose for hIFN-α expression and administered intragastrically in male Balb/C mice at the dose of 0.1 ml every other day for 2 weeks, with the mice receiving empty vector-transformed Bifidobacteria as the negative control and those having an equal volume of saline as the blank control. The percentages of mononuclear cell subsets in the thymus, spleen and blood were detected in the mice by flow cytometry, and the serum levels of IL-4, IL-12, IFN-γ and TNF-α were assayed using mouse cytokine FlowCytomix Kit.</p><p><b>RESULTS</b>The percentages of CD3⁺CD8⁺ and CD4⁺CD8⁺ cells in the thymus, CD3⁺CD4⁺, CD3⁺CD8⁺ and CD4⁺CD8⁺ cells in the spleen, and CD3⁺CD8⁺ cells in the blood all increased significantly in IFN group as compared with those in the negative and blank control groups (P<0.01 or 0.05). The serum level of IFN-γ also increased significantly (P<0.05) while IL-4 level remained unchanged in IFN group compared with those in the two groups.</p><p><b>CONCLUSION</b>Intragastric administration of hIFN-α-transformed Bifidobacterium promotes lymphocyte proliferation and maturation and increases the serum levels of Th1 cytokines in mice.</p>

Biochemical and pathological analysis of mice with type 2 diabetes mellitus induced by high-fat diet and low-dose streptozotocin injections / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the biochemical and pathological changes in mice with type 2 diabetes mellitus (T2DM) induced by high-fat diet combined with low-dose streptozotocin (STZ) injections.</p><p><b>METHODS</b>C57BL/6J mice were divided randomly into normal control group (NC group), high-fat diet group (HC group) and high-fat diet plus STZ group (HC+STZ group). The mice were fed on normal chow or a high-fat diet for 1 month before two introperitoneal injections of STZ (40 mg/kg) or citrate buffer with an interval of 24 h as appropriate. Fasting blood glucose (FBG) was detected every week for 4 weeks, and oral glucose tolerance test (OGTT) was performed one month after the injections, after which the biochemical profiles, islet and liver were evaluated by immunohistochemical and pathological analysis.</p><p><b>RESULTS</b>In HC+STZ group, FBG was above the cutoff value (13.89 mmol/L) in 75% of the mice at 1 week after STZ injections and in all the mice at two weeks except for the death of 1 mouse, with a success rate of modeling of 91.3%. FBG in HC group, though slightly higher than that in NC group, remained normal (6.8 mmol/L). The body weight in HC+STZ and HC groups was significantly higher than that in NC group after feeding but without obvious increases after the injections (P<0.01). Blood glucose in HC+STZ group at 0.5 to 2 h after OGTT and the area under curve (AUC) were higher than those in NC and HC groups (P<0.01); the AUC in HC group was a also higher than that in NC group (P<0.05). Plasma creatinine was significantly higher in HC+STZ group than in NC (P<0.01) and HC (P<0.05) groups. Insulin secretion by the islets decreased obviously in HC+STZ and HC group. The mice in HC+STZ group showed atrophy, fibrosis, and vacuolization in the islets with mild fatty liver but no visible renal pathologies.</p><p><b>CONCLUSION</b>High-fat diet and low-dose STZ injections can induce T2DM in mice with very similar biochemical and pathological changes to human T2DM and with such complications as fatty liver.</p>

Granzyme B-VEGF receptor-binding peptide fusion protein expressed in B. longum induces apoptosis of KDR-positive cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To express granzyme B-vascular endothelial growth factor (VEGF) receptor-binding peptide (GrB-VRB) fusion protein in Bifidobacteria longum (B. longum) and investigate the effects of this fusion protein on the proliferation and apoptosis of cells expressing VEGF receptor II, the kinase domain receptor (KDR).</p><p><b>METHODS</b>The recombinant expression vectors pBBADx-VRB, pBBADx-GrB and pBBADx-GrB-VRB were separately transformed into B. longum cells by electroporation. The expressed products were identified by enzyme-linked immunosorbent assay and Western blotting, and their effects on KDR-positive cells were analyzed using proliferation assay and TUNEL assay.</p><p><b>RESULTS</b>The expressed products were detected in both the supernatant and cellular fractions of B. longum cells. The recombinant GrB-VRB fusion protein reacted with such KDR-positive cells as human umbilical vein endothelial cells (HUVEC) and mouse colon cancer cell line CT-26, and caused obvious cell proliferation inhibition, cytotoxicity and cell apoptosis in these cells.</p><p><b>CONCLUSION</b>The recombinant GrB-VRB fusion protein secreted by the engineered B. longum cells can induce KDR-positive cell death as the result of GrB-induced cell apoptosis following the cell recognition by VRB.</p>

Cloning, purification and biological activity of human vascular endothelial growth factor fragment in E. coli / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To observe the effect of human vascular endothelial growth factor (VEGF) fragment (3 approximately 4 exon) in E. coli on anti-angiogenesis.</p><p><b>METHODS</b>Through RT-PCR amplification, endonuclease cut and DNA sequence analysis identification, hVEGF fragment cDNA was inserted into E. coli expression vector pTrcHis2A. The prokaryotic expression plasmid pTrcHis2A/VEGF(3 approximately 4) was constructed and transformed into TOP10F.</p><p><b>RESULTS</b>After 8hr isopropy-beta-D-thiogalactoside (IPTG) induction, VEGF fragment was expressed in 15% of total proteins through sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The expressed protein was highly antigenic and specific. The VEGF fragment was further purified by affinity, which could inhibit HUVEC proliferation and neovascularization of the chick chorioallantoic membrane.</p><p><b>CONCLUSION</b>VEGF fragment is anti-angiogenetic, which may potentially be used in oncologico-biological targeting therapy.</p>

HUMAN BONE MORPHOGENETIC PROTEIN 7 EXPRESSION IN RABBIT BONE MARROW STEM CELL TRANSFERRED BY RETROVIRAL VECTOR MEDIATED hBMP_7 GENE / 解放军医学杂志

The human bone morphogenetic protein 7 (hBMP 7) gene was reconstructed in retroviral vector and transferred into incasing cells PT67 by liposome mediated method.The clones of the cells transferred with BMP 7 were selected by G418, and targeted rabbit bone marrow stem cells were infected with the virus granules which secreted from PT67 cells and also selected by G418. The mRNA and protein of BMP 7 gene in transferred cells were analyzed with hybridization in situ and immunohistochemistry. BMP 7 retrovirus vetor was successfully reconstructed. Cells transferred by PLNCX 2 hBMP 7 expressed abundant human BMP 7 mRNA and protein in the cytoplasm. However positive findings were not found in those cells that were not transferred. It may be used to increase the osteogenic capability of BMSc in the study of bone tissue engineering.