Feeding a corn oil/sucrose-enriched diet enhances steatohepatitis in sedentary rats

The current study investigated the combined effects of feeding a high-fat/high-sucrose (HF/HS) diet to rodents rendered sedentary via hindlimb unloading (HU). For 3 wk before HU, male Wistar rats were fed chow or a diet in which 32% of calories were derived from corn oil fat and 48% of calories from sucrose. Feeding continued during an additional 3-wk period of HU. Subsequently, blood samples were collected for determination of circulating leukocyte counts, insulin levels, and portal vein endotoxin. Inflammation, necrosis, and steatosis were assessed in formalin-fixed liver sections. No biochemical or histological evidence of injury was observed in control rats fed chow or HF/HS. HU increased circulating neutrophils and resulted in hyperinsulinemia. Mild hepatic fat accumulation and minimal focal necroinflammation were observed in this group. Feeding HF/HS during HU exacerbated hyperinsulinemia, hepatic steatosis, Kupffer cell content, and cytokine expression. Significant portal endotoxemia was noted in HU rats but was not influenced by HF/HS diet. On the other hand, feeding HF/HS significantly enhanced lipid peroxidation end products in liver of HU rats by approximately threefold compared with chow-fed rats. In summary, these findings demonstrate that feeding a high-calorie diet potentiates steatosis and injury in sedentary HU rats. Mechanisms underlying enhanced injury most likely involved lipid peroxidation. Importantly, these findings suggest that dietary manipulation combined with physical inactivity can be used to model steatohepatitis.     

Differential immunoregulation of granulomatous inflammation, portal hypertension, and hepatic fibrosis in murine schistosomiasis mansoni

The present study investigates the immunoregulation of hepatic fibrosis in experimental murine schistosomiasis. Disease parameters measured were portal pressure, hepatic granuloma area, hepatic interstitial collagen, and glycosaminoglycans. C57BL/6 mice were infected with 25 Schistosoma mansoni cercariae and administered splenocytes or serum derived from uninfected mice or chronically infect syngeneic mice at 6 and 7 wk of infection. Immunologically mediated modulation was noted in animals receiving splenocytes derived from chronically infected mice. Both a reduction in portal pressure and hepatic granuloma areas were noted. Hepatic collagen content but not glycosaminoglycan content was reduced by the administration of either lymphoid cells or serum from chronically infected mice. The isotypic profile of hepatic interstitial collagens was modulated by both the administration of serum or lymphoid cells. Augmented levels of type III collagen was noted on administration of serum derived from chronically infected mice, whereas type I collagen levels were relatively elevated on administration of splenocytes. The data indicate that immunomodulation of inflammation and hepatic fibrosis can occur in murine schistosomiasis but that fibrotic events and inflammatory processes are independently modulated.     

Endotoxin enhances microvascular thrombosis in mouse cremaster venules via a TLR4-dependent, neutrophil-independent mechanism

Endotoxemia promotes adhesive interactions between platelets and microvascular endothelium in vivo. We sought to determine whether endotoxin (lipopolysaccharide, LPS) modified platelet thrombus formation in mouse cremaster venules and whether Toll-like receptor 4 (TLR4) and neutrophils were involved in the response. Intravital videomicroscopy was performed in the cremaster microcirculation of pentobarbital-anesthetized mice; venular platelet thrombi were induced with a light/dye endothelial injury model. C57BL/6 mice treated with Escherichia coli endotoxin had enhanced rates of venular platelet thrombus formation: the time to microvessel occlusion was reduced by approximately 50% (P < 0.005) compared with saline-treated animals. Enhanced microvascular thrombosis was evident as early as 2 h after LPS administration. LPS had no effect on thrombosis in either of two mouse strains with altered TLR4 signaling (C57BL/10ScNJ or C3H/HeJ), whereas it enhanced thrombosis in the control strains (C57BL/10J and C3H/HeN). LPS also enhanced platelet adhesion to endothelium in the absence of light/dye injury. Platelet adhesion, but not enhanced thrombosis, was inhibited by depletion of circulating neutrophils. LPS failed to enhance platelet aggregation ex vivo and did not influence platelet P-selectin expression, a marker of platelet activation. These findings support the notion that endotoxemia promotes platelet thrombus formation independent of neutrophils and without enhancement of platelet aggregation, via a TLR4-dependent mechanism.     

Subchronic endotoxin inhalation causes persistent airway disease

The endotoxin component of organic dusts causes acute reversible airflow obstruction and airway inflammation. To test the hypothesis that endotoxin alone causes airway remodeling, we have compared the response of two inbred mouse strains to subchronic endotoxin exposure. Physiological and biological parameters were evaluated after 1 day, 5 days, or 8 wk of exposure to endotoxin [lipopolysaccharide (LPS)] in endotoxin-sensitive (C3HeB/FeJ) and endotoxin-resistant (C3H/HeJ) mice. After 5 days or 8 wk of LPS exposure, only C3HeB/FeJ had elevated airway hyperreactivity to inhaled methacholine. Only the C3HeB/FeJ mice had significant inflammation of the lower respiratory tract after 1 day, 5 days, or 8 wk of LPS exposure. Stereological measurements of small, medium, and large airways indicated that an 8-wk exposure to LPS resulted in expansion of the submucosal area only in the C3HeB/FeJ mice. Cell proliferation as measured by bromodeoxyuridine incorporation contributed to the expansion of the submucosa and was only significantly elevated in C3HeB/FeJ mice actively exposed to LPS. C3HeB/FeJ mice had significantly elevated levels of interleukin-1beta protein in whole lung lavage after 1 day and 5 days of LPS exposure and significantly elevated protein levels of total and active transforming growth factor-beta1 in whole lung lavage fluid after 5 days of LPS exposure. Our findings demonstrate that subchronic inhalation of LPS results in the development of persistent airway disease in endotoxin-responsive mice.     

IL-10 deficiency augments acute lung but not liver injury in hemorrhagic shock

In hemorrhagic shock and trauma, patients are prone to develop systemic inflammation with remote organ dysfunction, which is thought to be caused by pro-inflammatory mediators. This study investigates the role of the immuno-modulatory cytokine IL-10 in the development of organ dysfunction following hemorrhagic shock. Male C57/BL6 and IL-10 KO mice were subjected to volume controlled hemorrhagic shock for 3 h followed by resuscitation. Animals were either sacrificed 3 or 24 h after resuscitation. To assess systemic inflammation, serum IL-6, IL-10, KC, and MCP-1 concentrations were measured with the Luminex? multiplexing platform; acute lung injury (ALI) was assessed by pulmonary myeloperoxidase (MPO) activity and lung histology and acute liver injury was assessed by hepatic MPO activity, hepatic IL-6 levels, and serum ALT levels. There was a trend towards increased IL-6 and KC serum levels 3 h after resuscitation in IL-10 KO as compared to C57/BL6 mice; however this did not reach statistical significance. Serum MCP-1 levels were significantly increased in IL-10 KO mice 3 and 24 h following resuscitation as compared to C57/BL6 mice. In IL-10 KO mice, pulmonary MPO activity was significantly increased 3 h following resuscitation and after 24 h histological signs of acute lung injury were more apparent than in C57/BL6 mice. In contrast, no significant differences in any liver parameters were detected between IL-10 KO and C57/BL6 mice. Our data indicate that an endogenous IL-10 deficiency augments acute lung but not liver injury following hemorrhagic shock.     

Studies on the induction of tolerance to alloantigens. II. The generation of serum factor(s) able to transfer alloantigen-specific tolerance for delayed-type hypersensitivity by portal venous inoculation with allogeneic cells

The administration of C3H/He spleen cells into allogeneic BALB/c mice via portal venous (p.v.) route resulted in C3H/He alloantigen-specific tolerance for delayed-type hypersensitivity (DTH) responses. When serum from these tolerant BALB/c mice were transferred into naive syngeneic BALB/c mice, the recipient mice lost the capability of generating DTH responses as induced by s.c. immunization with C3H/He cells. Tolerance was transferred only by serum from BALB/c mice inoculated p.v. with C3H/He cells, but not by serum from C3H/He mice inoculated p.v. with C3H/He cells, or BALB/c mice inoculated i.v. with C3H/He cells. This tolerogenic activity in serum from p.v. inoculated BALB/c mice was C3H/He alloantigen specific, because the transfer of the serum did not interfere with the development of anti-C57BL/6 DTH responses in recipient BALB/c mice. Such a serum factor(s) was inducible as early as 1 wk after the inoculation of C3H/He cells into BALB/c mice and not associated with anti-C3H/He alloantibody activity. Moreover, anti-C3H/He or C57BL/6-specific tolerogenic factor(s) prepared in the respective BALB/c or C3H/He mice was successfully transferred into totally allogeneic recipient mice, indicating no requirement of H-2, as well as non-H-2 restriction for the function of serum tolerogenic factor(s). Thus this study demonstrates that p.v. inoculation of allogeneic cells generates serum factor(s) able to transfer in H-2 and non-H-2-unrestricted manners the in vivo tolerance of the alloreactivity specific for alloantigens used for p.v. inoculation.     

Long-term colonization levels of Helicobacter hepaticus in the cecum of hepatitis-prone A/JCr mice are significantly lower than those in hepatitis-resistant C57BL/6 mice

Helicobacter hepaticus infection causes hepatitis in A/JCr mice but mild or no disease in C57BL/6 mice. Colonization of H. hepaticus in the cecum of experimentally infected A/JCr and C57BL/6 mice was quantified by use of real-time polymerase chain reaction (PCR) analysis with primers for the H. hepaticus cdtB gene and mouse 18srRNA. Eight-week-old mice were experimentally (n = 48) or sham (n = 24) infected with H. hepaticus, then were necropsied 6 months after infection. Liver specimens from experimentally infected mice had negative results of PCR analysis for H. hepaticus; thus, real-time quantification was not attempted. Quantitative PCR analysis of H. hepaticus in cecal specimens indicated that C57BL/6 mice were colonized to a greater extent than were A/JCr mice (P < 0.006). Appreciable typhlitis was not observed, but was consistent with that of previous reports; A/JCr mice developed more severe parenchymal necrosis, portal inflammation, and phlebitis in the liver (P < 0.0001), with mild disease observed in infected C57BL/6 mice. Thus, hepatitis in A/JCr mice caused by H. hepaticus infection is associated with significantly lower colonization levels of H. hepaticus in the cecum, compared with those of hepatitis-resistant C57BL/6 mice. Host responses of A/JCr mice that limit cecal colonization with H. hepaticus may have important roles in the pathogenesis of hepatic lesions.     

Gene expression profiling reveals unique pathways associated with differential severity of lyme arthritis

The murine model of Lyme disease provides a unique opportunity to study the localized host response to similar stimulus, Borrelia burgdorferi, in the joints of mice destined to develop severe arthritis (C3H) or mild disease (C57BL/6). Pathways associated with the response to infection and the development of Lyme arthritis were identified by global gene expression patterns using oligonucleotide microarrays. A robust induction of IFN-responsive genes was observed in severely arthritic C3H mice at 1 wk of infection, which was absent from mildly arthritic C57BL/6 mice. In contrast, infected C57BL/6 mice displayed a novel expression profile characterized by genes involved in epidermal differentiation and wound repair, which were decreased in the joints of C3H mice. These expression patterns were associated with disease state rather than inherent differences between C3H and C57BL/6 mice, because C57BL/6-IL-10(-/-) mice infected with B. burgdorferi develop more severe arthritis than C57BL/6 mice and displayed an early gene expression profile similar to C3H mice. Gene expression profiles at 2 and 4 wk postinfection revealed a common response of all strains that was likely to be important for the host defense to B. burgdorferi and mediated by NF-kappaB-dependent signaling. The gene expression profiles identified in this study add to the current understanding of the host response to B. burgdorferi and identify two novel pathways that may be involved in regulating the severity of Lyme arthritis.     

Protective effect of bile acids on the onset of fructose-induced hepatic steatosis in mice

Fructose intake is being discussed as a key dietary factor in the development of nonalcoholic fatty liver disease (NAFLD). Bile acids have been shown to modulate energy metabolism. We tested the effects of bile acids on fructose-induced hepatic steatosis. In C57BL/6J mice treated with a combination of chenodeoxycholic acid and cholic acid (100 mg/kg body weight each) while drinking water or a 30% fructose solution for eight weeks and appropriate controls, markers of hepatic steatosis, portal endotoxin levels, and markers of hepatic lipogenesis were determined. In mice concomitantly treated with bile acids, the onset of fructose-induced hepatic steatosis was markedly attenuated compared to mice only fed fructose. The protective effects of the bile acid treatment were associated with a downregulation of tumor necrosis factor (TNF)α, sterol regulatory element-binding protein (SREBP)1, FAS mRNA expression, and lipid peroxidation in the liver, whereas hepatic farnesoid X receptor (FXR) or short heterodimer partner (SHP) protein concentration did not differ between groups fed fructose. Rather, bile acid treatment normalized occludin protein concentration in the duodenum, portal endotoxin levels, and markers of Kupffer cell activation to the level of water controls. Taken together, these data suggest that bile acids prevent fructose-induced hepatic steatosis in mice through mechanisms involving protection against the fructose-induced translocation of intestinal bacterial endotoxin.     

Mouse strain difference in bile duct lesions induced by swine serum injections

The mouse strain difference in bile duct lesions was studied on male A/J, BALB/c, C57BL/6, C3H/He, DBA/2 and DDY mice 4 weeks old given intraperitoneal injections of swine serum (0.05 or 0.2 ml per mouse) twice a week for 4 weeks. The hepatic lesions were restricted to the portal tract. Biliary epithelial cells showed hypertrophy and hyperplasia, and eosinophilic and homogeneous or needle-shaped material appeared in the cytoplasm of such hypertrophied epithelial cells and in the ductular lumen. Around these damaged biliary epithelia, eosinophil leukocyte and plasma cell infiltration with proliferation of collagen fibres was commonly detected. These changes became more apparent with increasing size of bile duct. Such histopathological characteristics of hepatic lesions were essentially the same in all strains, but the severity showed a clear strain difference: the lesion was marked in the DDY, A/J and BALB/c strains, moderate in C3H/He and slight in C57BL/6 and DBA/2. A high production of anti-swine-serum antibodies associated with a marked increase in the number of mouse IgG-producing lymphocytes in the spleen was detected in the strains showing the marked hepatic lesions.     

Epigallocatechin gallate but not catechin prevents nonalcoholic steatohepatitis in mice similar to green tea extract while differentially affecting the gut microbiota

Catechin-rich green tea extract (GTE) protects against nonalcoholic steatohepatitis (NASH) by alleviating gut-derived endotoxin translocation and hepatic Toll-like receptor-4 (TLR4)–nuclear factor κB (NFκB) inflammation. We hypothesized that intact GTE would attenuate NASH-associated responses along the gut–liver axis to a greater extent than purified (−)-epigallocatechin gallate (EGCG) or (+)-catechin (CAT). Male C57BL/6J mice were fed a low-fat diet, a high-fat (HF) diet, or the HF diet with 2% GTE, 0.3% EGCG or 0.3% CAT for 8 weeks prior to assessing NASH relative to endotoxemia, hepatic and intestinal inflammation, intestinal tight junction proteins (TJPs) and gut microbial ecology. GTE prevented HF-induced obesity to a greater extent than EGCG and CAT, whereas GTE and EGCG more favorably attenuated insulin resistance. GTE, EGCG and CAT similarly attenuated serum alanine aminotransferase and serum endotoxin, but only GTE and EGCG fully alleviated HF-induced NASH. However, hepatic TLR4/NFκB inflammatory responses that were otherwise increased in HF mice were similarly attenuated by GTE, EGCG and CAT. Each treatment also similarly prevented the HF-induced loss in expression of intestinal TJPs and hypoxia inducible factor-1α and the otherwise increased levels of ileal and colonic TNFα mRNA and fecal calprotectin protein concentrations. Gut microbial diversity that was otherwise lowered in HF mice was maintained by GTE and CAT only. Further, microbial metabolic functions were more similar between GTE and CAT. Collectively, GTE catechins similarly protect against endotoxin–TLR4–NFκB inflammation in NASH, but EGCG and CAT exert differential prebiotic and antimicrobial activities suggesting that catechin-mediated shifts in microbiota composition are not entirely responsible for their benefits along the gut–liver axis.     

TLR4 promotes Cryptosporidium parvum clearance in a mouse model of biliary cryptosporidiosis

Cholangiocytes, the epithelial cells lining intrahepatic bile ducts, express multiple toll-like receptors (TLRs) and, thus, have the capacity to recognize and respond to microbial pathogens. In previous work, we demonstrated that TLR4, which is activated by gram-negative lipopolysaccharide (LPS), is upregulated in cholangiocytes in response to infection with Cryptosporidium parvum in vitro and contributes to nuclear factor-kappaB (NF-kB) activation. Here, using an in vivo model of biliary cryptosporidiosis, we addressed the functional role of TLR4 in C. parvum infection dynamics and hepatobiliary pathophysiology. We observed that C57BL mice clear the infection by 3 wk post-infection (PI). In contrast, parasites were detected in bile and stool in TLR4-deficient mice at 4 wk PI. The liver enzymes alanine transaminase (ALT) and aspartate transaminase (AST), and the proinflammatory cytokines tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and interleukin (IL)-6 peaked at 1 to 2 wk PI and normalized by 4 wk in infected C57BL mice. C57BL mice also demonstrated increased cholangiocyte proliferation (PCNA staining) at 1 wk PI that was resolved by 2 wk PI. In contrast, TLR4-deficient mice showed persistently elevated serum ALT and AST, elevated hepatic IL-6 levels, and histological evidence of hepatocyte necrosis, increased inflammatory cell infiltration, and cholangiocyte proliferation through 4 wk PI. These data suggest that a TLR4-mediated response is required for efficient eradication of biliary C. parvum infection in vivo, and lack of this pattern-recognition receptor contributes to an altered inflammatory response and an increase in hepatobiliary pathology.     

Comparative study on high fat diet-induced 4-hydroxy-2E-nonenal adducts in the hippocampal CA1 region of C57BL/6N and C3H/HeN mice

In the present study, we investigated the influences of a high fat diet (HD) fed for 12 weeks, on lipid peroxidation and antioxidant enzyme using 4-hydroxy-2E-nonenal (HNE)-modified proteins (HNE-mp) and Cu,Zn-superoxide dismutase (SOD1) in the hippocampal CA1 region (CA1) in C57BL/6N and C3H/HeN mice. Body weights and body weight gains were significantly higher in HD fed C57BL/6N mice than in low fat diet (LD) fed C57BL/6N and LD or HD fed C3H/HeN mice. In the HD fed C57BL/6N and C3H/HeN mice, HNE-mp immunoreactivity and protein levels were much higher than in the LD fed C57BL/6N or C3H/HeN mice. In particular, HNE-mp immunoreactivity and protein levels in HD fed C57BL/6N mice was higher than that in the HD fed C3H/HeN mice. SOD1 immunoreaction was detected in the non-pyramidal cells of C57BL/6N mice, while in the C3H/HeN mice SOD1 immunoreaction was observed in CA1 pyramidal cells. The SOD1 immunoreactivity in the LD fed C57BL/6N and C3H/HeN mice was slightly, but not significantly decreased compared to that in the HD fed C57BL/6N and C3H/HeN mice, respectively. In addition, ionized calcium-binding adapter molecule 1 (Iba-1) immunoreactive microglia in the HD fed C57BL/6N showed hypertrophy of cytoplasm, which is the characteristics of activated microglia. These results suggest that HD fed C57BL/6N mice are more susceptible to lipid peroxidation in the CA1 than in LD fed C57BL/6N and LD or HD fed C3H/HeN mice without any differences of SOD1 expression. In Koo Hwang and Il Yong Kim have contributed equally to this article.     

Cytokines regulate the pattern of rejection and susceptibility to cyclosporine therapy in different mouse recipient strains after cardiac allografting

We determined the role of cytokines in regulating the pattern of rejection and recipient susceptibility to cyclosporine (CsA) in a mouse cardiac allograft model. Hearts from C3H mice transplanted into untreated BALB/c (Th2-dominant) and C57BL/6 (Th1-dominant) mice showed different patterns of rejection. C3H allografts in BALB/c mice showed typical acute vascular rejection (AVR) with strong intragraft deposition and high serum levels of anti-donor IgG with predominant IgG1, while C3H allografts in C57BL/6 mice showed typical acute cellular rejection (ACR) with massive intragraft infiltration of CD4(+) and CD8(+) lymphocytes and low serum levels of anti-donor IgG with predominant IgG2a. Elevated intragraft mRNA expression of IL-2, IFN-gamma, and IL-12 mRNA was present in C57BL/6 recipients, whereas allografts in BALB/c mice displayed increased IL-4 and IL-10 mRNA levels. CsA therapy completely inhibited ACR and induced indefinite allograft survival in C57BL/6 recipients, while the same therapy failed to prevent AVR, and only marginally prolonged graft survival in BALB/c recipients. In contrast, rapamycin blocked AVR, achieving indefinite survival in BALB/c recipients, but was less effective at preventing ACR in C57BL/6 recipients. The disruption of the IL-12 or IFN-gamma genes in C57BL/6 mice shifted ACR to AVR, and resulted in concomitant recipient resistance to CsA therapy. Conversely, disruption of IL-4 gene in BALB/c mice markedly attenuated AVR and significantly prolonged allograft survival. These data suggest that the distinct cytokine profiles expressed by different mouse strains play an essential role in regulating the pattern of rejection and outcome of CsA/rapamycin therapy.     

Developmental changes in hepatic metallothionein, zinc, and copper levels in genetically altered mice.

Using mice that either overexpress metallothionein 1 (MT-1*) or do not express metallothionein 1 and 2 (MT-null) and a control strain (C57BL/6), the essential metal storage function of hepatic metallothionein and its subcellular localization were investigated during development. Hepatic metallothionein, zinc, and copper levels were measured in all groups from gestational day 20 to 60 days of age. Hepatic metallothionein levels were maximal during the perinatal period in both MT-1* and C57BL/6 mice with levels approximately three times higher in MT-1* mice. MT-null mice had no detectable hepatic metallothionein throughout development. Hepatic zinc levels were highest in the neonatal period of MT-1* and C57BL/6 mice and declined to adult levels by 30 days of age, while hepatic zinc levels in MT-null mice did not vary markedly throughout development. Hepatic copper profiles were very similar in MT-1* and MT-null mice as compared with the C57BL/6 mice. Correlation analysis showed a strong positive correlation between hepatic metallothionein and zinc levels in MT-1* mice, moderate correlation between hepatic metallothionein and metals in C57BL/6 mice, but only a very weak correlation between hepatic metallothionein and copper levels in MT-1* mice. Immunohistochemical localization showed specific nuclear staining in both MT-1* and C57BL/6 mice during the neonatal period with a gradual shift to the cytoplasm. The results show that hepatic metallothionein is a major determinant of zinc but not copper levels during murine development. Additionally, hepatic metallothionein levels and localization are regulated in a similar manner in MT-1* and C57BL/6 mice. The MT-null mice maintain a basel level of zinc sufficient for development, which was found to be 15.9 micrograms/g. This value was similar to the levels of hepatic zinc that was not bound to metallothionein in MT-1* and C57BL/6 mice during development.     

Regulation of adiponectin and its receptors in response to development of diet-induced obesity in mice

Adiponectin and its receptors play an important role in energy homeostasis and insulin resistance, but their regulation remains to be fully elucidated. We hypothesized that high-fat diet would decrease adiponectin but increase adiponectin receptor (AdipoR1 and AdipoR2) expression in diet-induced obesity (DIO)-prone C57BL/6J and DIO-resistant A/J mice. We found that circulating adiponectin and adiponectin expression in white adipose tissue are higher at baseline in C57BL/6J mice compared with A/J mice. Circulating adiponectin increases at 10 wk but decreases at 18 wk in response to advancing age and high-fat feeding. However, adiponectin levels corrected for visceral fat mass and adiponectin mRNA expression in WAT are affected by high-fat feeding only, with both being decreased after 10 wk in C57BL/6J mice. Muscle AdipoR1 expression in both C57BL/6J and A/J mice and liver adipoR1 expression in C57BL/6J mice increase at 18 wk of age. High-fat feeding increases both AdipoR1 and AdipoR2 expression in liver in both strains of mice and increases muscle AdipoR1 expression in C57BL/6J mice after 18 wk. Thus advanced age and high-fat feeding, both of which are factors that predispose humans to obesity and insulin resistance, are associated with decreasing adiponectin and increasing AdipoR1 and/or AdipoR2 levels.     

Effect of mouse strain variations and cortisone treatment on the establishment and growth of primary Echinococcus multilocularis hydatid cysts

The main purpose of this study was to determine the effects of cortisone on the number and size of primary Echinococcus multilocularis cysts developing in a moderately resistant strain of mice, i.e., C3H/HeJ. Computerized image analysis was used to measure the surface area occupied by hydatid cysts 10 wk after inoculation of the mice with E. multilocularis eggs. Our second objective was to compare the infectivity of primary E. multilocularis hydatid cysts in C57BL/6J-Ay/a (lethal yellow) mice with that in C57BL/6J-a/a (non-agouti black) mice. The data obtained show no difference between the C3H/HeJ and C57BL/6J-a/a strains of mice; yet, the image analysis method was able to detect a slight increase in the total cyst size within the Ay/a mutant of the C57BL/6J strain. Treatment of C3H/HeJ mice with cortisone drastically increased both the number of cysts and the average size of each cyst when the treatment occurred early in the infection.     

Characterization of a congenitally LPS-resistant, athymic mouse strain.

C57BL/10ScN (nu/nu) mice have B cells and macrophages unresponsive to a phenol-water extracted preparation of Escherichia coli K 235 LPS. This unresponsiveness was demonstrated in vitro by the inability of spleen cells to incorporate 3H-thymidine after a 48 hr incubation with LPS (Ph) and by the inability of LPS (Ph) to inhibit macrophage phagocytosis of 51 Cr-labeled, opsonized sheep erythrocytes. Furthermore, macrophage cultures stimulated with LPS (Ph) produced low levels of LAF and PGE2 when compared with macrophages from the LPS-sensitive C3H/HeN and C3H/HeN (nu/nu) strains. Therefore, the C57BL/10ScN (nu/nu) strain is similar in its LPS unresponsiveness to the well-characterized C3H/HeJ and C57BL/10ScCR strains. The combination of endotoxin unresponsiveness and the athymic nature of this mouse strain may provide a powerful new tool for studying the cellular events mediating endotoxicity.     

Development of glutathione peroxidase activity during dietary and genetic copper deficiency

Copper deficiency was produced in developing rodents to study a possible interaction between copper and the selenoenzyme, glutathione peroxidase (GSH-Px). Dietary copper deficiency was investigated in Sprague-Dawley rats and in three mouse strains (C57BL, C3H/HeJ, C58); genetic copper deficiency was studied in two of the mouse strains, C57BL and C3H/HeJ, using brindled mice. In certain cases it appeared that copper deficiency was associated with depressed liver GSH-Px activity; values from copper-deficient livers were 40–70% of control values. However, the decrease in liver GSH-Px in both rats and mice was only observed when body weight was also depressed and did not necessarily correlate with copper deficiency signs, such as lower serum ceruloplasmin or liver cytochrome oxidase activities. In weanling rats, serum GSH-Px activity was normal despite a 60% reduction in liver activity. Mouse liver GSH-Px activity rose fourfold during the first 3 weeks of life to 75% of the adult level. Rat liver GSH-Px also increased during the suckling period. When perinatal copper deficiency, nutritional or genetic, was severe enough to retard growth, liver GSH-Px activity was depressed. Unlike rats, adult murine liver GSH-Px was equivalent in males and females.