Endometrial receptivity defects and impaired implantation in diabetic NOD mice

Implantation failure is a major hurdle to a successful pregnancy. The high rate of postimplantation fetal loss in nonobese diabetic (NOD) mice is believed to be related to an abnormal decidual production of interferon (IFN)gamma. To address whether diabetes alters the natural events associated with successful implantation, certain morphological and molecular features of uterine receptivity in diabetic NOD (dNOD) mice were examined in normally mated pregnancy and in concanavalin A (ConA)-induced pseudopregnancy. As opposed to normoglycemic NOD (cNOD) mice, dNOD mice expressed retarded maturation of their uterine pinopodes and overexpressed MUC1 mucin at implantation sites (P < 0.001). Uterine production of leukemia inhibitory factor (LIF) and phosphorylation of uterine NFkappaBp65 and STAT3-Ty705 were found to be low (P < 0.01) during Day 4.5 postcoitum, whereas IFNgamma was aberrantly overexpressed. Loss of temporal regulation of progesterone receptor A (PR A) and PR B, together with aberrantly increased expression of the protein inhibitor of activated STAT-y (PIASy) (P < 0.01) and reduced recruitment (P < 0.01) of the latter to nuclear progesterone receptor sites were prominent features of decidualization failure occurring at peri-implantation in dNOD mice. In conclusion, the aberrant expression of endometrial IFNgamma in dNOD mice is associated with a nonreceptive endometrial milieu contributing to peri-implantation embryo loss in type 1 diabetes.     

Perturbation of the molecular clockwork in the SCN of non-obese diabetic mice prior to diabetes onset

Circadian disruption is associated with the development of diabetes. Non-obese diabetic (NOD) mice show abnormal diurnal profiles in energy balance and locomotor activity suggesting circadian misalignment. Therefore, we analyzed cFos and mPER1 as markers for rhythmic neuronal activity within the suprachiasmatic nucleus (SCN) of wildtype (WT) and non-diabetic (nNOD) as well as acutely diabetic NOD (dNOD) mice. cFos levels show a day/night difference in both WT and nNOD but not in dNOD. mPER1 levels did not show a day/night difference in both nNOD and dNOD. This suggests that disruption of SCN rhythmicity in NOD mice precedes the actual onset of diabetes.     

Scanning electron microscopy of the equine oviduct and observations on ciliary currents in vitro at day 2 after ovulation

There are considerable differences between mammalian species in the distribution and activity of ciliated cells within the oviduct, and limited information is available concerning either the distribution or activity of cilia within the equine oviduct. Patterns of ciliary activity were characterized in the ampulla and isthmus of oviducts recovered at 2 d after ovulation from 10 mares, and scanning electron microscopy was used to examine regional differences in the distribution of cilia in oviducts from 3 of these mares. Based upon the motility of 15 microm latex microspheres, ciliary activity was significantly (P < 0.001) greater in the ampullar oviduct compared with that of the isthmic oviduct. The direction of ciliary beat was consistently toward the uterus in all regions of the oviduct. Scanning electron microscopy revealed ciliated and secretory cells in both regions of the oviduct at 2 d after ovulation, with no apparent differences in the proportion of ciliated versus secretory cells.     

非肥胖型糖尿病小鼠成年神经发生的实验研究

目的:探讨异常免疫反应介导的糖尿病(DM)对大脑神经干/祖细胞(NSC/NPC)增殖的影响。方法:依据尿糖测定结果将非肥胖型糖尿病(NOD)小鼠分为发病组和未发病组,观察两组小鼠的体重变化和胰岛炎的严重程度。通过5-溴-2'-脱氧尿苷(BrdU)掺入和免疫荧光染色方法,观察两组小鼠海马齿状回(DG)和侧脑室下区(SVZ)的BrdU阳性细胞数量的变化,以评估NSC/NPC增殖情况。结果:发病组小鼠呈现出多饮、多食、多尿等糖尿病典型症状,体重较未发病组明显减低。发病组小鼠胰腺组织中炎症评分为3分的胰岛数量明显多于未发病组,且胰岛炎症的平均评分显著高于未发病组(P0.05)。与未发病组比较,发病组小鼠大脑海马DG区BrdU阳性细胞显著降低(P0.01);SVZ区的BrdU阳性细胞数量亦明显少于未发病组(P0.001)。结论:异常免疫反应介导的DM可抑制小鼠大脑NSC/NPC的增殖。     

Cytokine regulatory effects on alpha-1 proteinase inhibitor expression in NOD mouse islet endothelial cells

Human microvascular islet endothelial cells (IEC) exhibit specific morphological and functional characteristics that differ from endothelia derived from other organs. One of these characteristics is the expression of alpha-1 proteinase inhibitor (Api). In this study, we observed its expression in nonobese diabetic (NOD) mouse IEC, in relation to the occurrence of type 1 diabetes and in response to cytokines, namely IL-1 beta and IL-10. In addition, IL-10-deficient NOD mice as well as IL-10 transgenic NODs were studied. Results have demonstrated that Api expression is: (i) highly specific for IEC in NOD mouse islets, as for humans; (ii) linked to the occurrence of early type 1 diabetes, and iii) strongly modulated by Th1 and Th2 cytokines. In fact, Api mRNA found in pre-diabetic NOD animals is significantly reduced when they become hyperglycemic and disappears by 25 weeks of age, when mice are diabetic. Moreover, Api mRNAs are never seen in nondiabetic controls. Furthermore, in cultured NOD IEC, Api expression is downregulated by the addition of IL-1 beta and is upregulated by IL-10; it is always absent in IL-10-deficient NOD mice and overexpressed in IL-10 transgenic NODs, thus further supporting that this cytokine upregulates Api expression.     

Ghrelin cell density in the gastrointestinal tracts of animal models of human diabetes

Ghrelin cell density in the gastrointestinal tract of animal models of human diabetes type 1 and 2 was investigated. The animals used were non-obese diabetic (NOD) mice and obese diabetic mice. Ghrelin cells were detected by immunohistochemistry and quantified by computerized image analysis. Ghrelin-immunoreactive cells were detected in all animals studied. They were abundant in the oxyntic mucosa, patchy and few in the duodenum and rare in the colon. The density of ghrelin-immunoreactive cells decreased in diabetic, pre-diabetic NOD mice and in obese diabetic mice as compared to controls, though not statistically significant. It was concluded that the reduced density of ghrelin-immunoreactive cells in animal models of human diabetes type 1 and 2 might explain the slow gastric emptying and slow intestinal transit found in diabetes gastroenteropathy.     

Diabetes Increases the Expression of Hypothalamic Neuropeptides in a Spontaneous Model of Type I Diabetes, the Nonobese Diabetic (NOD) Mouse

1. Synthesis of oxytocin (OT) and arginine-vasopressin(AVP) is increased in induced models of Type I diabetes, such as thestreptozotocin model. However, these parameters have not yet been evaluated inspontaneous models, such as the nonobese diabetic mouse (NOD). Therefore, we studied in the magnocellular cells of the paraventricular nucleus (PVN)of nondiabetic and diabetic 16-week-old female NOD mice and control C57Bl/6mice, the immunocytochemistry of OT and AVP peptides and their mRNA expression, using nonisotopic in situ hybridization (ISH).2. In nondiabetic and diabetic NOD female mice, the number of OT- and AVP-immunoreactive cells were similar to those of the controls, whereas immunoreaction intensity was significantly higher for both peptides in diabetic NOD as compared with nondiabetic NOD and control C57Bl/6 mice.3. ISH analysis showed that the number of OT mRNA-containing cells was in the same range in the three groups, whereas higher number of AVP mRNA expressing cells was found in diabetic NOD mice. However, the intensity of hybridization signal was also higher for both OT and AVP mRNA in the diabetic group as compared with nondiabetic NOD and control mice.4. Blood chemistry demonstrated that haematrocrit, total plasma proteins, urea, sodium, and potassium were within normal limits in diabetic mice. Thus, NODmice were neither hypernatremic nor dehydrated.5. We suggest that upregulation of OT and AVP reflects a high-stress condition in the NOD mice. Diabetes may affect neuropeptide-producing cells of the PVN, with the increased AVP and OT playing a deleterious role on the outcome of the disease.     

Long-Lasting Expression of HO-1 Delays Progression of Type I Diabetes in NOD Mice

Heme oxygenase-1 (HO-1) is crucial in regulating oxidative injury. The present study was designed to assess whether HO-1 upregulation by cobalt protoporphyrin IX (CoPP) moderates or prevents the diabetic state in non-obese diabetic (NOD) mice, an animal model for Type 1 diabetes (T1D). HO-1 expression and HO activity were upregulated in the pancreas by the intermittent administration of CoPP. This was associated with decreases in blood glucose and pancreatic O2-, but increased pAKT and BcL-XL and cell survival. A considerable number of beta cells were preserved in the islets of CoPP-treated NOD mice, while none were found in untreated diabetic mice. The number of CD11c+ dendritic cells was decreased in the pancreas of CoPP-treated NOD mice (p     

Neonatal phytoestrogen exposure alters oviduct mucosal immune response to pregnancy and affects preimplantation embryo development in the mouse

Treatment of neonatal mice with the phytoestrogen genistein (50 mg/kg/day) results in complete female infertility caused in part by preimplantation embryo loss in the oviduct between Days 2 and 3 of pregnancy. We previously demonstrated that oviducts of genistein-treated mice are "posteriorized" as compared to control mouse oviducts because they express numerous genes normally restricted to posterior regions of the female reproductive tract (FRT), the cervix and vagina. We report here that neonatal genistein treatment resulted in substantial changes in oviduct expression of genes important for the FRT mucosal immune response, including immunoglobulins, antimicrobials, and chemokines. Some of the altered immune response genes were chronically altered beginning at the time of neonatal genistein treatment, indicating that these alterations were a result of the posteriorization phenotype. Other alterations in oviduct gene expression were observed only in early pregnancy, immediately after the FRT was exposed to inflammatory or antigenic stimuli from ovulation and mating. The oviduct changes affected development of the surviving embryos by increasing the rate of cleavage and decreasing the trophectoderm-to-inner cell mass cell ratio at the blastocyst stage. We conclude that both altered immune responses to pregnancy and deficits in oviduct support for preimplantation embryo development in the neonatal genistein model are likely to contribute to infertility phenotype.     

Effect of diabetic state on co-localization of substance P and serotonin in the gut in animal models

Changes in the numbers of serotonin- and substance P-immunoreactive (IR) cells occur in several animal models of diabetes. It is not known, however, whether these changes are a result of actual cell loss or are caused by modified gene expression in cells showing co-localization of serotonin and substance P. The pattern of mono- and co-expression of serotonin, as well as of substance P, was therefore investigated in gastrointestinal endocrine cells from animal models of human type 1 and type 2 diabetes, namely non-obese diabetic (NOD) and obese diabetic (ob/ob) mice. Immunocytochemical staining by the avidin-biotin complex method was performed for computerized image analysis of each cell type, and by immunofluorescence double staining to study co-localization. Tissues from antrum, proximal duodenum and distal colon were investigated. Co-localization of serotonin- and substance P-IR was found in all investigated parts of the gut. In antrum, substance P immunoreactivity was found exclusively in serotonin-IR cells. In both NOD and ob/ob mice there was a reduced number of substance P-IR cells, but an unchanged serotonin-IR cell count, which thus tallies with a shut-off of substance P expression in antral enterochromaffin cells. In duodenum, both diabetes models showed a decreased number of serotonin-IR cells. Furthermore there was a decreased number of substance P-IR cells in the type 2 model. The proportion of serotonin-IR cells showing substance P-immuno-reactivity was decreased in both diabetic models, thus indicating a shut-off of substance P-gene expression. However, this does not fully explain the changes in duodenum, but the diabetic state probably affects the number of mono-expressed cells as well. In colon, no change was found in diabetic mice regarding co-localization of substance P and serotonin. However, pre-diabetic NOD mice showed a decreased proportion of substance P in serotonin-IR cells, which might be explained by the increased number of serotonin-IR cells, combined with an unchanged number of substance P-IR cells. In conclusion, diabetic animal models of both type 1 and type 2 appear to have a combination of decreased expression of substance P in serotonin-IR cells of both antrum and duodenum, as well as a change in the number of mono-expressed cells. The pattern in colon, on the other hand, seems to be unaffected.     

The quest for the sea urchin egg receptor for sperm

The incretin glucagon-like peptide-1 (GLP-1) and other GLP-1 receptor agonists have been shown to cause both antiapoptotic as well as regenerative effects on beta-cells in different animal models for diabetes. Our aim of this study was to test the hypothesis that spontaneously diabetic non obese diabetic (NOD) mice show an altered expression of GLP-1 compared to normoglycemic age-matched controls as a consequence of a diabetic state. To do this we used an ELISA prototype for mouse GLP-1 to measure plasma total GLP-1 from recently diabetic NOD mice as well as from age-matched normoglycemic NOD mice (controls). We also stained sections of pancreatic glands for GLP-1 from diabetic NOD mice and controls. We found increased levels of plasma total GLP-1 in diabetic NOD mice, when compared to control mice, both from non-fasted mice and from mice fasted for 2h. Furthermore, diabetic NOD mice displayed a higher GLP-1 response to an oral glucose tolerance test, compared to control mice. We also found that sections of pancreatic glands from diabetic NOD mice had an increased GLP-1 positive islet area in regard to relative islet area (i.e. total islet area / total pancreas area of the sections) compared to control mice. To our knowledge, this study is the first to show increased levels of GLP-1 in plasma in spontaneously diabetic NOD mice. We suggest that these results might represent a compensatory mechanism of the diabetic NOD mice to counteract beta-cell loss and hyperglycemia.     

Significant role for Fas in the pathogenesis of autoimmune diabetes

Programmed cell death represents an important pathogenic mechanism in various autoimmune diseases. Type I diabetes mellitus (IDDM) is a T cell-dependent autoimmune disease resulting in selective destruction of the beta cells of the islets of Langerhans. beta cell apoptosis has been associated with IDDM onset in both animal models and newly diagnosed diabetic patients. Several apoptotic pathways have been implicated in beta cell destruction, including Fas, perforin, and TNF-alpha. Evidence for Fas-mediated lysis of beta cells in the pathogenesis of IDDM in nonobese diabetic (NOD) mice includes: 1) Fas-deficient NOD mice bearing the lpr mutation (NOD-lpr/lpr) fail to develop IDDM; 2) transgenic expression of Fas ligand (FasL) on beta cells in NOD mice may result in accelerated IDDM; and 3) irradiated NOD-lpr/lpr mice are resistant to adoptive transfer of diabetes by cells from NOD mice. However, the interpretation of these results is complicated by the abnormal immune phenotype of NOD-lpr/lpr mice. Here we present novel evidence for the role of Fas/FasL interactions in the progression of NOD diabetes using two newly derived mouse strains. We show that NOD mice heterozygous for the FasL mutation gld, which have reduced functional FasL expression on T cells but no lymphadenopathy, fail to develop IDDM. Further, we show that NOD-lpr/lpr mice bearing the scid mutation (NOD-lpr/lpr-scid/scid), which eliminates the enhanced FasL-mediated lytic activity induced by Fas deficiency, still have delayed onset and reduced incidence of IDDM after adoptive transfer of diabetogenic NOD spleen cells. These results provide evidence that Fas/FasL-mediated programmed cell death plays a significant role in the pathogenesis of autoimmune diabetes.     

Insulin binding to circulating erythrocytes in nonobese diabetic mice

Insulin binding to circulating erythrocytes was studied in nonobese diabetic (NOD) mice which develop insulinopenic diabetes mellitus spontaneously. NOD mice with a short duration of diabetes mellitus and mild insulinopenia did not show any change in insulin binding, while those with a long duration of diabetes mellitus and severe insulinopenia showed an increase in insulin binding compared with nondiabetic NOD mice (6.85 +/- 0.38% bound vs. 4.19 +/- 0.24% bound, p less than 0.01). This increase in insulin binding was due to an increase in the number of receptors. Insulin treatment of diabetic NOD mice significantly reduced the insulin binding by 64%, which resulted from a decrease in the number of the receptors. These results indicate that insulin binding to erythrocytes in NOD mice is controlled mostly by up-and-down regulation.     

Endothelin inhibition delays onset of hyperglycemia and associated vascular injury in type I diabetes: evidence for endothelin release by pancreatic islet beta-cells

This study investigated the role of endothelin-1 for hyperglycemia, vascular, and pancreatic injury in early type I diabetes in non-obese-diabetic (NOD) mice. Endothelium dependent relaxation to acetylcholine and vascular gene expression of endothelin converting enzyme (ECE) isoforms 1 and 2 were studied as indicators of vascular injury. Endothelial NO bioactivity in the aorta was reduced in diabetic NOD mice while vascular expression of ECE-1 and ECE-2 mRNA was increased compared with controls (all p<0.05). Vascular histology was normal in all animals. Unexpectedly, treatment of prediabetic NOD mice for 6 weeks with the orally active ET(A) receptor antagonist BSF461314 prevented onset of diabetes without affecting insulitis severity. ET(A) receptor blockade also restored abnormal endothelial NO bioactivity and reduced ECE-1 and ECE-2 gene expression in NOD mice to levels comparable with healthy controls (p<0.05). Moreover, secretion of endothelin-1 in a time-dependent fashion was observed by pancreatic islet beta-cells cultured in vitro. These data suggest a critical role for ET(A) receptor signaling in the development of autoimmune forms of diabetes and the early vascular injury associated with it.     

Regulation of complement-3 protein expression in human and mouse oviducts

The human oviduct derived embryotrophic factor-3 (ETF-3) contains complement protein-3 (C3) and its derivates. Although C3 is not embryotrophic, it is converted into the embryotrophic derivative, iC3b in the presence of embryos and oviductal cells. The regulation of C3 production in the oviduct is not known. The objectives of this study were to investigate the effects of presence of preimplantation embryos and hormones on C3 expression in the oviducts in vitro and in vivo. The expression of C3 in the oviduct of pregnant mice was compared to that of pseudo-pregnant mice. The hormonal action on C3 expression was studied in the ovariectomized mouse oviducts and human oviductal epithelial (OE) cells. The results showed that the level of C3 mRNA in the mouse oviduct was high on Day 1 and Day 2, but decreased to a minimum on Day 4 of pregnancy, whereas that of pseudo-pregnancy remained relatively stable within the same period. The protein levels of C3 and iC3b specific fragments, alpha-115 and alpha-40, respectively in the mouse oviductal luminal fluid were highest on Day 3 of pregnancy, when the embryos were expected to be most sensitive to the embryotrophic activity of ETF-3. Estrogen elevated C3 expression in the ovariectomized mouse oviduct and the OE cells. Progesterone suppressed estrogen-induced C3 expression in the mouse oviduct, but had no effect on OE cells. In conclusion, the presence of embryo and steroid hormones regulate the synthesis and secretion of oviductal C3.     

Altered dendritic cells (DC) might be responsible for regulatory T cell imbalance and autoimmunity in nonobese diabetic (NOD) mice

Nonobese diabetic (NOD) mice spontaneously develop diabetes, an auto-immune disease characterized by the destruction of insulin-secreting beta-cells by autoreactive T cells. Defects in development and/or functions of dendritic cells (DC) might be critical in eliciting the auto-immune reaction to beta cells in this model. In this paper, DC differentiation in NOD mice was investigated in vitro using bone marrow-derived progenitors (BM-DC) in the presence of GM-CSF and IL-4 or spleen-derived progenitors in the presence of GM-CSF and early acting cytokines such as Flt-3L and IL-6 (SPL-DC). In both culture systems, the absolute number of NOD DC generated was strongly reduced as compared to control strains. In addition, both BM-DC and SPL-DC from NOD mice show defective differentiation into mature DC in conventional culture conditions as indicated by low expression of MHC class II and CD80 molecules among CD11c positive cells and low capacity to stimulate allogeneic T cells. However, DC achieved full maturation when exposed to LPS, except for MHC class II expression that remained decreased. Ex vivo analysis confirmed an unusual phenotype of NOD DC. Both sets of results are thus consistent with a specific defect of DC maturation in these mice.     

Atrial natriuretic peptide (ANP): a study of ANP and its mRNA in cardiocytes,and of plasma ANP levels in non-obese diabetic mice

Summary Atrial natriuretic peptide (ANP) levels in cardiocytes and plasma were examined by using immunohistochemistry, electron microscopy, and radioimmunoassay in non-obese diabetic mice (NOD). Cardiocyte ANP mRNA expression was measured by the polymerase chain reaction method. ANP immunoreactivity in the auricular cardiocytes was more prominent in hyperglycemic mice (NOD-h) than in normoglycemic mice (NOD-n). Ultrastructural examination showed that auricular cardiocytes of the NOD-h group contained more cytoplasmic granules than cells of the NOD-n group. Ultrastructural morphometry indicated that the number of granules per auricular cardiocyte was significantly larger in the NOD-h group than in the NOD-n group. (P<0.01), whereas the granule diameter was significantly smaller in the NOD-h group (P<0.01). Radioimmunoassay showed that ANP levels in the NOD-h auricular cardiocytes were significantly higher than those in the NOD-n cardiocytes (P<0.01); the opposite was true in plasma. Cardiocyte ANP mRNA expression was lower in the NOD-h group than in the NOD-n group.     

Synchronized gastric electrical stimulation improves delayed gastric emptying in nonobese mice with diabetic gastroparesis.

The aim of this study was to investigate the effect and mechanism of synchronized gastric electrical stimulation (SGES) on gastric emptying in nonobese mice with diabetic gastroparesis (DB-GP). Eight control mice and 48 nonobese diabetic (NOD) mice with two pairs of gastric electrodes were used in this study. The study included seven groups in a randomized order [control, diabetes (DB), DB-GP, DB + SGES, DB-GP + SGES, DB-GP + Atropine, and DB-GP + SGES + Atropine groups]. In the control, DB, DB-GP, and DB-GP + Atropine groups, gastric emptying was measured in BLAB/cJ mice (control group) or NOD mice with a duration of diabetes of 0-7 days (DB group) or 28-35 days (DB-GP or DB-GP + Atropine group). In the DB + SGES, DB-GP + SGES, and DB-GP + SGES + Atropine groups, the experiment was the same as the corresponding DB, DB-GP, and DB-GP + Atropine groups except that SGES was applied during the experiment. SGES was applied via the proximal pair of electrodes and synchronized with the intrinsic gastric slow waves. The following results were obtained: 1) gastric emptying was delayed in NOD mice with a duration of diabetes of 28-35 days; 2) SGES was able to significantly increase gastric emptying in both diabetic mice and diabetic gastroparetic mice; and 3) the excitatory effect of SGES was completely blocked by atropine. SGES accelerates gastric emptying in NOD mice with diabetic gastroparesis. The effect of SGES on gastric emptying is mediated via the cholinergic pathway. These findings suggest that SGES may have a therapeutic potential for treating patients with diabetic gastroparesis.