High glucose dialysate enhances peritoneal fibrosis through upregulating glucose transporters GLUT1 and SGLT1 / 浙江大学学报·医学版

To investigate the role of glucose transporter 1 (GLUT1) and sodium-glucose cotransporter 1 (SGLT1) in high glucose dialysate-induced peritoneal fibrosis.Thirty six male SD rats were randomly divided into 6 groups (6 in each):normal control group, sham operation group, peritoneal dialysis group (PD group), PD+phloretin group (PD+T group), PD+phlorizin group (PD+Z group), PD+phloretin+phlorizin group (PD+T+Z group). Rat model of uraemia was established using 5/6 nephrotomy, and 2.5% dextrose peritoneal dialysis solution was used in peritoneal dialysis. Peritoneal equilibration test was performed 24 h after dialysis to evaluate transport function of peritoneum in rats; HE staining was used to observe the morphology of peritoneal tissue; and immunohistochemistry was used to detect the expression of GLUT1, SGLT1, TGF-β1 and connective tissue growth factor (CTGF) in peritoneum. Human peritoneal microvascular endothelial cells (HPECs) were divided into 5 groups:normal control group, peritoneal dialysis group (PD group), PD+phloretin group (PD+T group), PD+phlorezin group (PD+Z group), and PD+phloretin+phlorezin group (PD+T+Z group). Real time PCR and Western blotting were used to detect mRNA and protein expressions of GLUT1, SGLT1, TGF-β1, CTGF in peritoneal membrane and HPECs., compared with sham operation group, rats in PD group had thickened peritoneum, higher ultrafiltration volume, and the mRNA and protein expressions of GLUT1, SGLT1, CTGF, TGF-β1 were significantly increased (all<0.05); compared with PD group, thickened peritoneum was attenuated, and the mRNA and protein expressions of GLUT1, SGLT1, CTGF, TGF-β1 were significantly decreased in PD+T, PD+Z and PD+T+Z groups (all<0.05). Pearson's correlation analysis showed that the expressions of GLUT1, SGLT1 in peritoneum were positively correlated with the expressions of TGF-β1 and CTGF (all<0.05)., the mRNA and protein expressions of GLUT1, SGLT1, TGF-β1, CTGF were significantly increased in HPECs of peritoneal dialysis group (all<0.05), and those in PD+T, PD+Z, and PD+T+Z groups were decreased (all<0.05). Pearson's correlation analysis showed that the expressions of GLUT1, SGLT1 in HPECs were positively correlated with the expressions of TGF-β1 and CTGF (all<0.05).High glucose peritoneal dialysis fluid may promote peritoneal fibrosis by upregulating the expressions of GLUT1 and SGLT1.

Effects of estrogen and phytoestrogens on endometrial leakage in ovariectomized rats and the related mechanisms / 生理学报

Phytoestrogens, a group of plant-derived non-steroidal compounds that can behave as estrogens by binding to estrogen receptors, have drawn great attention for their potentially beneficial effects on human health. However, there are few studies investigating the potential side effects of phytoestrogens on the reproductive system. The present study was to elucidate the effects of 17β-estradiol (E2), progesterone (P4), and phytoestrogens genistein (Gen), resveratrol (Res), and phloretin (Phl) on eosinophilic infiltration of the ovariectomized rat uterus and endometrial vascular permeability, and to analyze the underlying mechanisms. The ovariectomized rats received daily subcutaneous injections of E2, E2+P4, P4, Gen, Res, Phl, or an equivalent volume of vehicle for 21 days, and sham-operated animals (Sham rats) were used as the controls. Hematoxylin-eosin staining revealed a marked increase in uterine eosinophilic infiltrations in ovariectomized rats treated with E2, E2+P4 or P4, which was associated with increased expression of vascular endothelial growth factor (VEGF), nuclear factor-κB (NF-κB), and tumor necrosis factor-α (TNF-α) proteins as determined by immunohistochemical and Western blot analysis. However, all three phytoestrogens had no markedly effect on the uterine eosinophilic infiltration and the expressions of VEGF, NF-κB, and TNF-α in the uterus of ovariectomized rats. Our data demonstrate that E2 alone or in combination with P4 increases uterine eosinophilic infiltration which is related with vascular hyperpermeability caused by VEGF, NF-κB and TNF-α, whereas phytoestrogens Gen, Res, and Phl, have no such an effect.

Anti-inflammatory and immunosuppressive effect of phloretin / 药学学报

This study investigated the effect of phloretin (Ph) on the proliferation, activation, and cell-cycle distribution of mouse T lymphocytes and NO production and phagocytosis of macrophages. Carboxyfluorescein diacetatesuccinimidyl ester (CFDA-SE) staining plus flow cytometry assay was employed to obtain the proliferation-related index (PI) of lymphocytes. The expression levels of CD69 and CD25 on T lymphocytes stimulated with Con A were evaluated with flow cytometry after staining with fluorescent monoclonal antibody. Cell-cycle distribution of T lymphocytes was analyzed by propidium iodide staining. Griess kit was used to evaluate the NO production and fluorescent microbeads were used to analyze the phagocytosis ability of macrophages. Our results showed that phloretin (40, 60, and 80 micromol x L(-7)) significantly inhibited the proliferation of T lymphocytes and the PI reduced from 1.41 +/- 0.13 to 1.34 +/- 0.16, 1.19 +/- 0.12 and 1.07 +/- 0.06, respectively. Phloretin significantly inhibited the expression of CD69 and CD25 (P < 0.01). The cell cycle distribution analysis showed that phloretin could induce a cell cycle arrest at G0/G1 phase. NO production of LPS +IFN-gamma group of macrophages was (26.72 +/- 3.57) micromol x L(-1), and was significantly reduced by phloretin (P < 0.01). And phagocytosis rate of macrophages was significantly reduced by phloretin (P < 0.01). The results demonstrate that phloretin might be developed into a new immuosuppressive drug.

The Effects of Ethanol and Acetaldehyde on Corpus Cavernosal Smooth Muscle of the Rabbit / 대한남성과학회지

PURPOSE: This study is to assess the pharmacologic effects of ethanol and its metabolite, acetaldehyde on potassium channels of the corpus cavernosal smooth muscle of the rabbit. MATERIALS AND METHODS: Cavernosal strips from New Zealand white rabbits were harvested and pharmacophysiologic organ bath studies were executed. In equilibrium state after incubation, zaprinast (PDE5 inhibitor) induced relaxations were monitored in strips precontracted with phenylephrine (PE, 10(-4)M). The inhibitory effects of ethanol and acetaldehyde (2, 20, 40, 80 mmol) on zaprinast-induced relaxations were recorded. Pinacidil (K(ATP) channel opener) and phloretin (BK channel opener) were tested to reverse the inhibitory effects of ethanol and acetaldehyde on zaprinast-induced relaxations. RESULTS: Both ethanol and acetaldehyde inhibited the zaprinast-induced relaxations in a dosedependent manner (p<0.05). Both pinacidil and phloretin abolished the inhibition by both ethanol and acetaldehyde (p<0.05). Ethanol and acetaldehyde inhibits cavernosal relaxation, possibly through BK channels and K(ATP) channels. CONCLUSIONS: These results suggest that ethanol and its metabolite may affect the corpus cavernosal smooth muscle directly and lead to consequent erectile dysfunction. Furthermolecular and electrophysiological studies will help reveal the underlying mechanisms to which this process occurs.

Phloretin induces apoptosis of BEL-7402 cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To examine the effect of phloretin on apoptosis of BEL-7402 cells.</p><p><b>METHODS</b>The viability changes of BEL- 7402 cells as a result of phloretin-induced toxicity were analyzed using MTT assay, and the cell morphology changes were observed with fluorescence microscope. Flow cytometry was used to analyze the cell cycle and mitochondrial membrane potential changes, and chromogenic substrate assay performed to detect caspase activity.</p><p><b>RESULTS</b>Phloretin induced obvious cytotoxicity against BEL-7402 cells with IC50 of 89.23 microg/mL. The growth curve demonstrated decreased growth of the cells as phloretin concentration increased. Cell apoptosis occurred 24 h after treatment with 40-160 microg/mL phloretin. Morphological, the cells exposed to phloretin exhibited nuclear chromatin condensation and increased fluorescence intensity. The activity of caspase-9 reached the peak level 12 h after phloretin exposure, and leak levels of caspase-6 and caspase-3 activities occurred 18 and 24 h after the exposure, respectively.</p><p><b>CONCLUSION</b>Phloretin can induce BEL-7402 cell apoptosis though the mitochondrial pathway.</p>

Effect of Ascorbic Acid on Corneal Endothelial Function

It has been reported that ascorbic acid[AA]appears to be actively taken up by the corneal endothelium and protect the endothelium against harmful effects of the oxidative reactions. To investigate the effect of ascorbic acidon the corneal endothelial function, rabbit`s corneas were mounted in the in vitro specular microscope. Corneal endothelium was perfused with ascorbic acid, then switched to AA plus ouabain solution, and vice versa. Also, phloretin was perfused onto the endothelium with AA and ouabain. Andcorneal endothelium was perfused with GBR or AA solution followed by perfusion with ouabain. Corneal thickness was measured during the perfusion and the corneal swelling rate calculated. Corneal endothelial permeability was also measured after perfusion of ascorbic acid. Perfusion with AA showed no corneal swelling, but swelling rate was even lower than GBR control. Corneal endothelial permeability did not change upon AA perfusion. In corneas preperfused with ouabain, AA added to ouabain solution decreased corneal swelling rates induced by ouabain solution[19.9 vs. 40.5 micrometer/hr]. The corneas preperfused with AA also showed decreased swelling rates with subsequent perfusion of ouabain added to AA solution[21.7 vs.28.6 micrometer/ hr]. Phloretin inhibited the effect of AA.However, when ouabain was removed, the corneal swelling plateaued but did not return to baseline thickness in both AA and GBR perfusion.The results of this study showed that AA can increase corneal endothelial pump function and reduce corneal swelling caused by ouabain.