Characterization of Kupffer cells in livers of developing mice

Abstract Background Kupffer cells are well known macrophages of the liver, however, the developmental characteristics of Kupffer cells in mice are not well understood. To clarify this matter, the characteristics of Kupffer macrophages in normal developing mouse liver were studied using light microscopy and immunocytochemistry. Methods Sections of liver tissue from early postnatal mice were prepared using immunocytochemical techniques. The Kupffer cells were identified by their immunoreactivity to the F4/80 antibody, whereas endothelial cells were labelled with the CD-34 antibody. In addition, Kupffer cells and endothelial cells were labelled by systemically injected fluorescently labelled latex microspheres. Tissue slices were examined by fluorescence microscopy. Results Intravenous or intraperitonal injections of microspheres yielded similar patterns of liver cell labelling. The F4/80 positive Kupffer cells were labelled with both large (0.2 μm) and small (0.02 μm) diameter microspheres, while endothelial cells were labelled only with the smaller diameter microspheres. Microsphere labelling of Kupffer cells appeared stable for at least 6 weeks. Cells immunoreactive for F4/80 were identified as early as postnatal day 0, and these cells also displayed uptake of microspheres. Numbers of F4/80 Kupffer cells, relative to numbers of albumin positive hepatocytes, did not show a significant trend over the first 2 postnatal weeks. Conclusions Kupffer cells of the developing mouse liver appear quite similar to those of other mammalian species, confirming that the mouse presents a useful animal model for studies of liver macrophage developmental structure and function

A role for endocannabinoids in viral-induced dyskinetic and convulsive phenomena.

Dyskinesias and seizures are both medically refractory disorders for which cannabinoid-based treatments have shown early promise as primary or adjunctive therapy. Using the Borna disease (BD) virus rat, an animal model of viral encephalopathy with spontaneous hyperkinetic movements and seizure susceptibility, we identified a key role for endocannabinoids in the maintenance of a balanced tone of activity in extrapyramidal and limbic circuits. BD rats showed significant elevations of the endocannabinoid anandamide in subthalamic nucleus, a relay nucleus compromised in hyperkinetic disorders. While direct and indirect cannabinoid agonists had limited motor effects in BD rats, abrupt reductions of endocannabinoid tone by the CB1 antagonist SR141716A (0.3 mg/kg, i.p.) caused seizures characterized by myoclonic jerks time-locked to periodic spike/sharp wave discharges on hippocampal electroencephalography. The general opiate antagonist naloxone (NLX) (1 mg/kg, s.c.), another pharmacologic treatment with potential efficacy in dyskinesias or L-DOPA motor complications, produced similar seizures. No changes in anandamide levels in hippocampus and amygdala were found in convulsing NLX-treated BD rats. In contrast, NLX significantly increased anandamide levels in the same areas of normal uninfected animals, possibly protecting against seizures. Pretreatment with the anandamide transport blocker AM404 (20 mg/kg, i.p.) prevented NLX-induced seizures. These findings are consistent with an anticonvulsant role for endocannabinoids, counteracting aberrant firing produced by convulsive agents, and with a functional or reciprocal relation between opioid and cannabinoid tone with respect to limbic convulsive phenomena

Cellular organization of normal mouse liver: a histological, quantitative immunocytochemical, and fine structural analysis

The cellular organization of normal mouse liver was studied using light and electron microscopy and quantitative immunocytochemical techniques. The general histological organization of the mouse liver is similar to livers of other mammalian species, with a lobular organization based on the distributions of portal areas and central venules. The parenchymal hepatocytes were detected with immunocytochemical techniques to recognize albumin or biotin containing cells. The macrophage Kupffer cells were identified with F4-80 immunocytochemistry, Ito stellate cells were identified with GFAP immunocytochemistry, and endothelial cells were labeled with the CD-34 antibody. Kupffer cells were labeled with intravascularly administered fluorescently labeled latex microspheres of both large (0.5 μm) and small (0.03 μm) diameters, while endothelial cells were labeled only with small diameter microspheres. Neither hepatocytes nor Ito stellate cells were labeled by intravascularly administered latex microspheres. The principal fine structural features of hepatocytes and non-parenchymal cells of mouse liver are similar to those reported for rat. Counts of immunocytochemically labeled cells with stained nuclei indicated that hepatocytes constituted approximately 52% of all labeled cells, Kupffer cells about 18%, Ito cells about 8%, and endothelial cells about 22% of all labeled cells. Approximately, 35% of the hepatocytes contained two nuclei; none of the Kupffer or Ito cells were double nucleated. The presence of canaliculi and a bile duct system appear similar to that reported for other species. The cellular organization of the mouse liver is quite similar to that of other mammalian species, confirming that the mouse presents a useful animal model for studies of liver structure and function

Neurotrophic factors rescue basal forebrain cholinergic neurons and improve performance on a spatial learning test.

This study investigated whether animals sustaining experimental damage to the basal forebrain cholinergic system would benefit from treatment with exogenous neurotrophic factors. Specifically, we set out to determine whether neurotrophic factors would rescue damaged cholinergic neurons and improve behavioral performance on a spatial learning and memory task. Adult rats received bilateral injections of either saline (controls) or 192 IgG-saporin to damage basal forebrain cholinergic neurons (BFCNs). Two weeks later, animals received implants of an Alzet mini-pump connected to cannulae implanted bilaterally in the lateral ventricles. Animals received infusions of nerve growth factor (NGF), neurotrophin 3 (NT3), a combination of NGF and NT3, or a saline control over a 4-week period. Compared to saline-treated controls, animals sustaining saporin-induced damage to BFCNs took significantly more trials to learn a delayed match to position task and also performed more poorly on subsequent tests, with increasing delays between test runs. In contrast, animals infused with neurotrophins after saporin treatment performed significantly better than animals receiving saline infusions; no differences were detected for performance scores among animals infused with NGF, NT3, or a combination of NGF and NT3. Studies of ChAT immunnocytochemical labeling of BFCNs revealed a reduction in the numbers of ChAT-positive neurons in septum, nucleus of diagonal band, and nucleus basalis in animals treated with saporin followed by saline infusions, whereas animals treated with infusions of NGF, NT3 or a combination of NGF and NT3 showed only modest reductions in ChAT-positive neurons. Together, these data support the notion that administration of neurotrophic factors can rescue basal forebrain cholinergic neurons and improve learning and memory performance in rats

Neurotrophic factors rescue basal forebrain cholinergic neurons and improve performance on a spatial learning test.

This study investigated whether animals sustaining experimental damage to the basal forebrain cholinergic system would benefit from treatment with exogenous neurotrophic factors. Specifically, we set out to determine whether neurotrophic factors would rescue damaged cholinergic neurons and improve behavioral performance on a spatial learning and memory task. Adult rats received bilateral injections of either saline (controls) or 192 IgG-saporin to damage basal forebrain cholinergic neurons (BFCNs). Two weeks later, animals received implants of an Alzet mini-pump connected to cannulae implanted bilaterally in the lateral ventricles. Animals received infusions of nerve growth factor (NGF), neurotrophin 3 (NT3), a combination of NGF and NT3, or a saline control over a 4-week period. Compared to saline-treated controls, animals sustaining saporin-induced damage to BFCNs took significantly more trials to learn a delayed match to position task and also performed more poorly on subsequent tests, with increasing delays between test runs. In contrast, animals infused with neurotrophins after saporin treatment performed significantly better than animals receiving saline infusions; no differences were detected for performance scores among animals infused with NGF, NT3, or a combination of NGF and NT3. Studies of ChAT immunnocytochemical labeling of BFCNs revealed a reduction in the numbers of ChAT-positive neurons in septum, nucleus of diagonal band, and nucleus basalis in animals treated with saporin followed by saline infusions, whereas animals treated with infusions of NGF, NT3 or a combination of NGF and NT3 showed only modest reductions in ChAT-positive neurons. Together, these data support the notion that administration of neurotrophic factors can rescue basal forebrain cholinergic neurons and improve learning and memory performance in rats

Development, differentiation, and vascular components of subcutaneous and intrahepatic Hepa129 tumors in a mouse model of hepatocellular carcinoma.

Tumor models in mice offer opportunities for understanding tumor formation and development of therapeutic treatments for hepatocellular carcinoma. In this study, subcutaneous or intra-hepatic Hepa129 tumors were established in C3H mice. Tumor growth was determined by daily measurements of subcutaneous tumors and post-mortem studies of subcutaneous and intrahepatic tumors. Administration of Edu was used to determine cell generation dates of tumor cells. Immunohistochemistry with antibodies directed at CD31 or CD34, and intravenous injection of labeled tomato lectin revealed tumor vasculature. Tissue sections also were processed for immunohistochemistry using a panel of antibodies to proteoglycans. Comparison of Edu labeled cells with immunoreactivity allowed determination of development and differentiation of tumor cells after cell generation. Subcutaneous and intrahepatic tumors displayed similar growth over 3 weeks. Immunohistochemistry showed strong labeling for glypican-3, 9BA12, and chondroitin sulfate of tumors in both loci, while normal liver was negative. Tumor regions containing Edu labeled cells did not show significant immunohistochemical labeling for the tumor markers until 2-3 days after Edu treatment; overlap of Edu labeled cells and immunohistochemically labeled tumor regions appeared to reach a maximum at 5 days after Edu treatment. Ectopic subcutaneous tumors displayed vascular ingrowth as the tumor cells expressed immunocytochemical markers; subcutaneous tumors displayed significantly more vascular elements than did intrahepatic tumors