Sickness behavior is accentuated in rats with metabolic disorders induced by a fructose diet.

This study investigated behavioral responses to an immune challenge among animals with fructose-induced metabolic disorders. Adult male Wistar rats were provided either water or a fructose solution (10%) for 5 weeks. Sickness behaviors were assessed 2h following the injection of either a lipopolysaccharide (LPS) or vehicle. The rats were subjected to an open field test, a social interaction test, a food intake test and a fever evaluation. Cytokine expression was assessed in both adipose tissue and hypothalamus samples. The neural response was assessed in the forebrain immunohistochemistry for c-Fos. Compared with the control group, the fructose diet induced dyslipidemia and significantly higher plasma total cholesterol, HDL-cholesterol, triglyceride, and glucose levels as well as both epididymal and retroperitoneal adiposity. Furthermore, in response to LPS (1 mg/kg), the rats subjected to a fructose diet exhibited exacerbated sickness behaviors and accentuated febrile responses. LPS induced Fos protein expression in several areas of the brains of the control rats; however, higher numbers of Fos-positive cells were observed in the brains of the rats that were fed a fructose diet. Moreover, larger increases in cytokine expression were observed in both the hypothalamus and the adipose tissue of the obese rats compared with the control rats in response to LPS. In this study, fructose diets played an important role in both the induction of metabolic disorders and the modulation of sickness behaviors in response to an immunological challenge, most likely through the induction of cytokines in the hypothalamus.

Hypotensive effect of aqueous extract of Averrhoa carambola L. (Oxalidaceae) in rats: an in vivo and in vitro approach.

AIM OF THE STUDY: Averrhoa carambola L. (Oxalidaceae) leaves are used in Brazilian traditional medicine to treat hypertension. This study was conducted to evaluate the hypotensive effect of the aqueous extract of Averrhoa carambola (AEAc) and its underlying mechanisms in the isolated rat aorta. MATERIALS AND METHODS: The effect of AEAc on the mean arterial pressure (MAP) was determined in vivo in anesthetized rats. In vitro, thoracic aortic rings were isolated and suspended in organ baths, and the effects of AEAc were studied by means of isometric tension recording experiments. In HPLC analysis, the fingerprint chromatogram of AEAc was established. RESULTS: In normotensive rats, AEAc (12.5-50.0 mg/kg, i.v.) induced dose-dependent hypotension. In vitro, AEAc caused a depression in the E(max) response to phenylephrine without a change in sensibility. Also, in a depolarized Ca(2+)-free medium, AEAc inhibited CaCl(2)-induced contractions and caused a concentration-dependent rightward shift of the response curves, indicating that AEAc inhibited the contractile mechanisms involving extracellular Ca(2+) influx. CONCLUSIONS: These results demonstrate the hypotensive effects of AEAc, and these effects may, in part, be due to the inhibition of Ca(2+), which supports previous claims of its traditional use.

Hepatic morphological alterations, glycogen content and cytochrome P450 activities in rats treated chronically with N(omega)-nitro-L-arginine methyl ester (L-NAME).

Chronic treatment of rats with N(omega)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) biosynthesis, results in hypertension mediated partly by enhanced angiotensin-I-converting enzyme (ACE) activity. We examined the influence of L-NAME on rat liver morphology, on hepatic glycogen, cholesterol, and triglyceride content, and on the activities of the cytochrome P450 isoforms CYP1A1/2, CYP2B1/2, CYP2C11, and CYP2E1. Male Wistar rats were treated with L-NAME (20 mg/rat per day via drinking water) for 2, 4, and 8 weeks, and their livers were then removed for analysis. Enzymatic induction was produced by treating rats with phenobarbital (to induce CYP2B1/2), beta-naphthoflavone (to induce CYP1A1/2), or pyrazole (to induce CYP2E1). L-NAME significantly elevated blood pressure; this was reversed by concomitant treatment with enalapril (ACE inhibitor) or losartan (angiotensin II AT(1) receptor antagonist). L-NAME caused vascular hypertrophy in hepatic arteries, with perivascular and interstitial fibrosis involving collagen deposition. Hepatic glycogen content also significantly increased. L-NAME did not affect fasting glucose levels but significantly reduced insulin levels and increased the insulin sensitivity of rats, based on an intraperitoneal glucose tolerance test. Immunoblotting experiments indicated enhanced phosphorylation of protein kinase B and of glycogen synthase kinase 3. All these changes were reversed by concomitant treatment with enalapril or losartan. L-NAME had no effect on hepatic cholesterol or triglyceride content or on the basal or drug-induced activities and protein expression of the cytochrome P450 isoforms. Thus, the chronic inhibition of NO biosynthesis produced hepatic morphological alterations and changes in glycogen metabolism mediated by the renin-angiotensin system. The increase in hepatic glycogen content probably resulted from enhanced glycogen synthase activity following the inhibition of glycogen synthase kinase 3 by phosphorylation.

A review of trafficking and activation of uterine natural killer cells.

PROBLEM: Enrichment of uterine natural killer (uNK) cells occurs during pregnancy in many species. However, functions of uNK cells and regulation of their uterine homing are not fully defined. In mice and women, uNK cells contribute to angiogenesis, a role reviewed here and now addressed in a mammal with an alternative placental type. METHODS OF STUDY: To address lymphocyte functions, RNA from murine or porcine endometrium and lymphocytes purified from endometrium were analyzed using real-time or reverse transcription PCR. To address homing potential, human blood CD56(+) lymphocytes were evaluated using both RNA and functional adhesion to endothelium presented under shear force in frozen sections of gestation day 7 C57Bl/6J implantation sites. Women were serially sampled over a menstrual cycle or a clinical preparatory cycle for embryo transfer. RESULTS: Activation of murine uNK cells is associated with much greater increases in transcription for Eomes than for T-bet (Tbx21). Lymphocytes from normal porcine implantation sites transcribe vascular endothelial growth factor, placental growth factor, interferon-gamma and hypoxia-inducible factor (HIF)-1alpha. In fertile women, increases in L-selectin- and alpha4-integrin-mediated interactions between CD56(+) cells and endothelium occur at luteinizing hormone (LH) surge (cycling women) to oocyte pick up or embryo transfer, then return to pre-LH levels. CONCLUSIONS: Uterine lymphocytes may universally promote pregnancy-associated endometrial angiogenesis. Recruitment of uNK precursor cells from blood appears to occur in a window promoted by rising plasma estrogen and LH and limited by rising progesterone.

Expression of hypoxia-inducible factor-1alpha in the cutaneous lesions of BALB/c mice infected with Leishmania amazonensis.

The hypoxia-inducible factor-1alpha (HIF-1alpha) is expressed in response to hypoxia and has been recently demonstrated in a variety of cells such as tumor cells and tumor-associated macrophages. Several characteristics of leishmanial lesions in humans and in animal models, such as microcirculation impairment, metabolic demand for leukocyte infiltration into infected tissue, parasite proliferation, and secondary bacterial infection, are strong indications of a hypoxic microenvironment in the lesions. We evaluated HIF-1alpha expression in the cutaneous lesions of BALB/c mice during Leishmania amazonensis infection. Immunohistochemical analyses of the lesions demonstrated, only in the later stages of infection when the lesion size is maximal and parasite burden is enormous and massive numbers of recruited macrophages and ulcers are observed, positive HIF-1alpha-infected cells throughout the lesions. HIF-1alpha is expressed mainly in the cytoplasm and around parasites inside the parasitophorous vacuoles of macrophages. This is the first evidence that macrophages in the microenvironment of lesions caused by a parasite produce a hypoxia-inducible factor.

Update on pathways regulating the activation of uterine Natural Killer cells, their interactions with decidual spiral arteries and homing of their precursors to the uterus.

Virgin adult C57Bl/6J mouse uterus contains a population of small, non-granulated Natural Killer (NK) cells with balanced expression of NK cell activating and inhibiting LY49 receptors. Coincident with blastocyst implantation and decidualization, uterine (u)NK cells become activated. The surface glycoslyation of uNK changes, the cells proliferate and they induce production of interferon (IFN)gamma, perforin, serine esterases and other molecules, including angiogenic factors. Mouse strains genetically ablated in uNK cells fail to undergo modification of spiral artery segments that branch from the uterine artery and feed into the placenta and these mice do not sustain a robust decidualization response. IFN-gamma is thought, from bone marrow transplantation and therapeutic studies, to be the key uNK-cell derived mediator regulating gene expression in vascular and decidual tissues. Here, we review recent studies showing that IL-15 is the critical cytokine controlling uNK cell differentiation and that uNK cells are activated by either IL-12 or IL-18 and by other factors when both IL-12 and IL-18 are genetically absent from implantation sites. We address possible roles of the IFN-gamma regulated gene alpha2-macroglobulin (alpha2-M) in regulation of the position of fetal trophoblast within the walls of the spiral arteries, and we discuss approaches that have been successful in evaluating mechanisms involved in homing of mouse uNK cell precursors to the uterus. These approaches maybe applicable to studies in women. Our studies show that complex immuno-physiological events contribute to spiral artery modification by mid-gestation in mice.

Uterine natural killer cells: insights into their cellular and molecular biology from mouse modelling.

In primates, including women, and in rodents, natural killer lymphocytes (NK cells) have a unique relationship with the decidualizing uterus. Implantation sites from genetically modified and transplanted mice have proven useful models for understanding potential mechanisms involved in the recruitment, activation and functions of human CD56(bright) uterine (u)NK cells. Key findings are reviewed in this article. In mice, uNK precursor cells are recruited from secondary lymphoid tissues and are activated coincident with their uterine arrival. uNK cells proliferate, produce cytokines (interferon gamma (IFN-gamma) and interleukin 18 (IL-18) and IL-27), and terminally differentiate into granulated lymphocytes. Many uNK cells proliferate within the myometrium at each implantation site forming a structure, the mesometrial lymphoid aggregate of pregnancy (MLAp) that surrounds blood vessels servicing each placenta. Post-mitotic uNK cells are abundant within decidua basalis; frequently (<25%) associating with spiral arteries, intramurally and intraluminally. From mid-gestation, numbers of uNK cells decline. Studies of implantation sites in mice lacking uNK cells, IFN-gamma, components of IFN-gamma-induction and -signalling pathways or IFN-gamma-regulated genes indicate that uNK cell-derived IFN-gamma is essential in triggering pregnancy-induced spiral artery modification. Decidual maintenance and uNK cell death are additional effects of uNK cell-derived IFN-gamma. Thus, during the first half of gestation, uNK cells contribute to and sustain important changes in the maternal placental bed.