Egg production of Clonorchis sinensis in different strains of inbred mice.

In order to compare the intraspecific variation in host-parasite relationship of Clonorchis sinensis, six strains of inbred mice, ICR, DDY, GPC, BALB/c, nude and DS, were infected orally with 20 metacercariae of C. sinensis. The biologic incubation period of C. sinensis was the shortest in DDY mice, 21.2 days in average, followed by GPC 21.4, BALB/c and DS 23.2, ICR and nude 23.4 days, respectively. The fertile period of the fluke was also the longest in the DDY strain, 164 days on average, followed by GPC 132, BALB/c 97, nude 37, DS 32 and ICR 28 days. The egg-laying capacity of the fluke in DDY and GPC was relatively high and stable compared with the other four strains of mice. It was found that there are intraspecific variations in biologic incubation period, fertile period, and fecundity of C. sinensis. The DDY mouse is likely to be the most suitable experimental animal among the six strains of the mice tested.     

Strain variation in the susceptibility and immune response to Clonorchis sinensis infection in mice

Mice have shown various susceptibility to infection by Clonorchis sinensis. To compare the intra-specific variation in the host-parasite relationship of C. sinensis, 6 strains of mice (ICR, BALB/c, C57BL/6, DDY, CBA/N, and C3H/HeN) with 3 different haplotypes were evaluated on their susceptibility. The worm recovery rate and immunological responses were observed after 4 and 8 weeks of infection with 30 metacercariae. The highest worm recovery rate was observed as 20.7% in the C3H/HeN strain after 4 weeks of infection along with histopathological changes. The rate was 10.0% in C57BL/6 mice after 8 weeks. ICR, BALB/c, and CBA/N showed elevated levels of IgE at both time points when compared to the rest of the strains. The serum IgG1 and IgG2a levels were elevated in most of the strains; however, the C57BL/6 strain showed a lower level of IgG2a that indicated the IgG1 predominance over IgG2a. The production of IL-4 after concanavalin-A stimulation of splenocytes slightly increased among the mouse strains except C3H/HeN after 4 or 8 weeks of infection, but each strain produced high levels of IFN-γ after 8 weeks, which implied mixed Th1/Th2 responses. ICR, DDY, CBA/N, and C3H/HeN strains showed a significantly increased level of IL-10 after 8 weeks as compared to C57BL/6. All of the strains showed an increased level of IL-13 and suggested fibrotic changes in the mice. In conclusion, mice are insusceptible to infection with C. sinensis; however, the C57BL/6, BALB/c and ICR strains are relatively susceptible after 8 weeks of infection among the six strains. Worm expulsion may be one of the causes of low susceptibility of C3H/HeN mice strain at the 8th week. Elevated IgE, IFN-γ, and IL-13 of infected mice suggest both Th1 and Th2 responses that may be related to the low host susceptibility.     

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.     

Histochemical characteristics of glycoproteins in the bile duct system of mice immunized with swine serum

The bile duct system of BALB/c and DDY mice, which were immunized with swine serum (SS) or not, was examined histochemically. Biliary epithelial cells of the SS-treated BALB/c mice, which were positively stained with periodic acid-Schiff (PAS) and had binding sites of Dolichos biflorus (DBA), were thought to secrete neutral glycoproteins with terminal N-acetyl-D-galactosamine residues. Those of the SS-treated DDY mice were however negatively or weakly stained with any histochemical stainings. On the other hand, glandular epithelial cells of the SS-treated mice of both strains, which were positively stained with high iron diamine-alcian blue (HID-AB) and had binding sites of DBA, Griffonia simplicifolia-II (GS-II), Ulex europaeus-I (UEA-I), and Triticum vulgaris (WGA), were thought to secrete glycoproteins with terminal sialic acid residues. Biliary and glandular epithelial cells of the normal mice contained only a small amount of glycoproteins showing similar histochemical characteristics to those in the SS-treated BALB/c mice. BALB/c mice immunized with SS were thought to be very useful for the investigation of production and secretion of glycoproteins in the bile duct system as well as being good model of bile duct disease.     

Histochemical characteristics of glycoproteins in the bile duct system of mice immunized with swine serum

Summary The bile duct system of BALB/c and DDY mice, which were immunized with swine serum (SS) or not, was examined histochemically. Biliary epithelial cells of the SS-treated BALB/c mice, which were positively stained with periodic acid-Schiff (PAS) and had binding sites of Dolichos biflorus (DBA), were thought to secrete neutral glycoproteins with terminal N-acetyl-d-galactosamine residues. Those of the SS-treated DDY mice were however negatively or weakly stained with any histochemical stainings. On the other hand, glandular epithelial cells of the SS-treated mice of both strains, which were positively stained with high iron diamine-alcian blue (HID-AB) and had binding sites of DBA, Griffonia simplicifolia-II (GS-II), Ulex europaeus-I (UEA-I), and Triticum vulgaris (WGA), were thought to secrete glycoproteins with terminal sialic acid residues. Biliary and glandular epithelial cells of the normal mice contained only a small amount of glycoproteins showing similar histochemical characteristics to those in the SS-treated BALB/c mice. BALB/c mice immunized with SS were thought to be very useful for the investigation of production and secretion of glycoproteins in the bile duct system as well as being good model of bile duct disease.     

Anti-tumor effects of allogeneic bone marrow transplantation in (NZB X NZW)F1 hybrids with spontaneous lymphosarcoma

Untreated female (NZB X NZW)F1 hybrid mice (B/W F1) were found to develop lymphosarcoma spontaneously as they aged. Tumor incidence was evaluated in B/W F1 mice immunosuppressed with total lymphoid irradiation (TLI) and in TLI-conditioned B/W F1 mice reconstituted with 3 X 10(7) BALB/c bone marrow (BM) cells. BALB/C leads to B/W F1 chimerism (79 to 89% BALB/c-type cells) was confirmed by typing peripheral blood lymphocytes with specific alloantisera and complement by using a microcytotoxicity assay. Chimeras showed no clinical signs of graft-vs-host disease (GVHD). TLI-treated mice seemed to show a slightly accelerated onset of lymphosarcoma as compared with untreated controls, but the difference was not significant (p = 0.08). BALB/c leads to B/W F1 chimeras reconstituted at 1 to 3 mo of age (25 mice) developed no tumors for an observation period of 18 mo after transplantation. In contrast, tumors developed in 24/130 of age-matched controls, and in 13/57 of TLI-treated nonreconstituted age-matched B/W F1 mice. Tumor incidence in BALB/c leads to B/W F1 chimeras transplanted at an older age (9 to 11 mo) was similar to that observed in age-matched TLI-treated B/W F1 mice and age-matched untreated controls. The data suggests that the high naturally occurring incidence of lymphosarcoma could be reversed by reconstituting TLI-treated mice with BM cells (p = 0.027). Thus, allogeneic BM transplantation may exert potent graft-vs-tumor effects (GVT) when tumor susceptible hosts are reconstituted at an early age, whereas GVT is relatively ineffective at an advanced age, which probably correlates with an advanced stage of tumor development. Allogeneic BM transplantation should be additionally explored as a potential clinical tool for eradication of certain solid tumors in adjunct to high-dose radiochemotherapy, inasmuch as GVT seems to be independent of GVHD.     

The genotype of bone marrow-derived inflammatory cells does not account for differences in skeletal muscle regeneration between SJL/J and BALB/c mice

This study determined whether the genotype of bone marrow-derived inflammatory cells contributes to the more pronounced leukocytic exudation and extensive new muscle formation seen in SJL/J compared with BALB/c mice after a crush-injury (Mitchell et al. 1992). Female SJL/J mice were whole-body irradiated and reconstituted with male bone marrow from the BALB/c strain, and irradiated BALB/c females reconstituted with male SJL/J bone marrow. The mice were allowed to recover for 3 weeks and the tibialis anterior muscle (in a leg which had been protected from irradiation) was injured by crushing. At 3 and 10 days after injury the extent of necrotic debris, mononuclear leukocytic infiltration and new muscle formation was assessed in the muscles. The SJL/J mice reconstituted with BALB/c bone marrow showed extensive mononuclear leukocytic infiltration and clearance of necrotic debris when compared with BALB/c mice reconstituted with SJL/J bone marrow, and these strain-specific differences mirrored those seen with control bone marrow reconstituted hosts and non-irradiated hosts. The results show that the genotype of the bone marrow-derived macrophages is not responsible for the superior regeneration of crush-injured skeletal muscle in SJL/J mice, and it appears that factors intrinsic to the muscle tissue may be of central importance.     

Young F mice spontaneously generate cytotoxic T cells against parental targets.

Spleen cells from young (AKR/J female x BALB/c) or (BALB/c female x AKR/J)F1 mice can spontaneously generate effector cytotoxic T lymphocytes (CTL), in a 5-day primary in vitro culture, which lyse target cells from AKR/J and BALB/c but not allogeneic mice. These spontaneous CTL responses first appear when spleen cells are taken from F1 mice at 3 to 4 weeks of age, are maximum at about 5 weeks, and have declined by week 7. The fact that these spontaneous CTL responses are never detectable in the spleen cell cultures from any ages of parental AKR/J and BALB/c mice makes them unique properties of the F1 mice.     

Prevention of colon carcinogenesis and carcinoma metastasis by orally administered bovine lactoferrin in animals

Bovine lactoferrin (bLF), a milk protein known to have bacteriostatic properties was examined for its preventive effects on colon and other organ carcinogenesis and experimental metastasis. (Experiment 1) The influence on colon carcinogenesis was investigated in male rats treated with azoxymethane (AOM), then received 2 or 0.2% bLF for 36 weeks. Significant reduction in the incidence (27% and 46% of the control, respectively) and number of adenocarcinomas of the large intestine was observed. (Experiment 2) In BALB/c mice bearing subcutaneous (s.c.) implants of colon carcinoma 26 (Co 26Lu). bLF demonstrated significant inhibition of spontaneous lung metastasis (approximately 43% of the control). Number of cytotoxic asialoGM1+ and CD8+ cells in white blood cells increased (171% and 122% of control, respectively) after treatment. Results of those experiments indicate that bLF remarkably prevents colon carcinogenesis and lung metastasis of colon carcinoma cells, possibly due to increasing cytotoxic cells in the peripheral blood.     

MuMTV antigen expression and mammary tumor incidence in non-inbred dd mice

The expression of mammary tumor virus (MTV) antigen in the milk and various organs of three non-inbred dd mouse stocks (ddO, ddN and ddY) was examined by the immunodiffusion (ID) and micro-immunodiffusion (micro-ID) tests. The rate of MTV antigen expression in the milk was 100% at the first lactation in ddO (6/6) and ddN mice (10/10), and 23% in ddY mice (3/13). Mammary tumor incidence was 13% (mean tumor age: 12.0 months), 32% (9.6 months) and 10% (11.5 months) in ddO, ddN and ddY mice, respectively, In F1 hybrids between MTV-free BALB/c females and dd males, a high level of MTV antigen was detected by the ID test in the milk of (BALB/c X ddO) F1, however, the levels in (BALB/c X ddN) F1 and (BALB/c X ddY) F1 mice were low at the first lactation and elevated with the advance of lactation number. Mammary tumor incidence had a trend to be higher and earlier in these F1 hybrids than in non-inbred dd stocks. The development of mammary tumors and detection of MTV antigen in F1 hybrids indicate the extrachromosomal transmission of MTV by male dd mice. The micro-ID test has shown that the mammary tumors, mammary glands, male genital organs except for the testis and the salivary gland expressed MTV antigen, with a high frequency of suggesting that secondary male genital organs may play an important role in MTV infection in mice.     

Abnormal glucose metabolism in murine cytomegalovirus (MCMV)-infected mice

Five strains of male and female mice were infected with salivary gland-passaged murine cytomegalovirus (SG-MCMV) intraperitoneally. Although none of them became hyperglycemic, 13-30% of BALB/c male and female, ICR/Slc male and female and C57BL/6J male mice had abnormal values in glucose tolerance tests (GTT) 14 to 30 day post infection. Serum insulin levels in BALB/c male mice were low and infective virus was detected in the pancreas during the acute phase of infection. Histopathology showed mild edematous changes with inflammatory cell infiltrations in the pancreas. Viral antigen was located in acinar cells and occasionally in beta cells by an immunofluorescence test.     

Alleviative effects of quercetin and onion on male reproductive toxicity induced by diesel exhaust particles

Diesel exhaust particles (DEPs) are particulate matter from diesel exhaust that contain many toxic compounds, such as polyaromatic hydrocarbons (PAHs). Some toxicities of PAH are thought to be expressed via aryl hydrocarbon receptors (AhRs). The male reproductive toxicity of DEPs might depend on AhR activation induced by PAHs. We hypothesized that AhR antagonists protect against the male reproductive toxicity of DEPs. Quercetin is a flavonoid and a well-known AhR antagonist, while onion contains many flavonoids, including quercetin. Hence, we examined whether quercetin and onion have alleviative effects against the male reproductive toxicity induced by DEPs. BALB/c male mice were fed quercetin- or onion-containing diets and received 10 injections of DEP suspension or vehicle into the dorsal subcutaneous layer over 5 weeks. The mice were euthanized at 2 weeks, after the last treatment, and their organs were collected. Daily sperm production and total incidence of sperm abnormalities were significantly affected in the DEP groups as compared with the vehicle group, but the total incidence of sperm abnormalities in the quercetin + DEP-treated mice was significantly reduced as compared with the DEP-treated mice. The numbers of Sertoli cells were significantly decreased in DEP-treated mice as compared with the vehicle-treated mice, but, the numbers of Sertoli cells were significantly increased in the quercetin and the onion + DEP-treated mice as compared with the DEP-treated mice. These results clearly indicate alleviative effects of quercetin and onion against the male reproductive toxicity induced by DEP.     

Hypoxia increases erythropoiesis and decreases thrombocytopoiesis in mice: a comparison of two mouse strains

Several previous studies have shown that hypoxia increases erythropoiesis and decreases thrombocytopoiesis in mice. It has been postulated that the thrombocytopenia is caused by stem cell competition between the erythrocytic and megakaryocytic cell lines. In the present work, we compared the effects of severe hypoxia (5.5-6.0% O2) in both male and female C3H and BALB/c mice by measuring their abilities to produce red blood cells and platelets. All mice had significant increases in packed cell volumes and marked decreases in platelet production after hypoxia; however, there were significant differences in the degree of stimulation in the two mouse strains. After 14 days of hypoxia, the percentage of 35S incorporation into platelets, total circulating platelet counts and total circulating platelet masses were lower in C3H mice than in BALB/c mice, but platelet sizes were larger. Also, hypoxia caused greater changes in male mice than in female mice, with male C3H mice showing the greatest increase in packed cell volumes and the lowest platelet counts of all mice tested. The least responses were observed in female BALB/c mice. BALB/c mice had higher P50 (right-shifted O2 dissociation curves) and lower erythrocyte 2,3-diphosphoglycerate values than C3H mice, indicating a lower hemoglobin O2 affinity for BALB/c mice. The results indicate that the effects of hypoxia are not direct upon platelet production, but that the thrombocytopenia is a result of stimulation of erythropoiesis. These data support the stem cell competition hypothesis and illustrate that the degree of the inverse relationship between red blood cells and platelet production of hypoxic mice is dependent, to a large degree, upon the sex and strain of mice that are used.     

Effects of hypoxia on megakaryocyte size and number of C3H and BALB/c mice.

In an effort to explain the different platelet production capabilities of both normal and hypoxic male and female C3H and BALB/c mice, megakaryocyte size and number were determined utilizing bone marrow from both normal and hypoxic mice. The results indicate that normal BALB/c female mice have increased numbers of megakaryocytes, but of smaller size compared with either BALB/c male mice or to both sexes of C3H mice. An inverse relationship between the size and number of megakaryocytes was found in both normal and hypoxic mice; therefore, to evaluate total megakaryocyte characteristics, we calculated total megakaryocyte masses (TMM). With hypoxia, megakaryocyte number decreased, whereas megakaryocyte size increased. Despite the increase in megakaryocyte size, hypoxia caused a significant decrease in TMM (P less than 0.005) in all mice, but female C3H mice had higher TMM (P less than 0.05) than did female BALB/c mice. These data show that hypoxia decreases TMM in mice, and that the effect is greater in C3H mice than in BALB/c mice.     

Age and strain dependence of O6-methylguanine DNA methyltransferase activity in mice

The activity of the DNA repair protein O6-methylguanine DNA methyltransferase (MT) was compared in liver extracts from female ICR and male C57BL/6 mice at various ages (3-130 weeks old). Similar patterns of overall enzyme activity were observed in both strains with O6-MT activity being relatively low in young mice (3 or 8 weeks old). However, the activity significantly increased after adolescence (middle age), thereafter decreasing with old age (over 100 weeks old) to a level equivalent to that found in young mice. In an additional strain difference study, O6-MT activities in liver extracts from 4 strains of mice were compared at 5 and 30 weeks of age. Although a similar age-associated increase of enzyme activity in adolescence was confirmed in all 4 strains investigated, the closed-colony ICR mice differed from the inbred strains in demonstrating significantly higher levels of O6-MT activity in females than in males. However, the same tendency was also observed in a comparison of the sexes in 30-week-old C3H/HeN, C57BL/6 and BALB/c mice.     

Immunological basis for susceptibility and resistance to pulmonary blastomycosis in mouse strains

The immunological basis for a >10-fold resistance of outbred CD-1 mice compared to inbred BALB/c mice to pulmonary blastomycosis was investigated. Bronchoalveolar macrophages (BAM) from CD-1 mice killed yeast cells of Blastomyces dermatitidis (Bd) by 25% and this increased to 59% when activated by IFN-gamma. In contrast, BAM from BALB/c mice lacked significant killing (5%) of Bd but could be activated by IFN-gamma for enhanced killing (19%). Peritoneal macrophages (PM) from CD-1 mice had significant fungicidal activity for Bd (43%) and this increased to 63% with IFN-gamma treatment. By contrast, PM from BALB/c mice did not significantly kill Bd (14%) but were activated by IFN-gamma for significant killing (24%). Fungicidal activity of peripheral blood polymorphonuclear neutrophils (PMN) from CD-1 (87%) was greater than that of BALB/c (75%) (P<0.05). Macrophage inflammatory protein-1alpha (MIP-1alpha) production by BAM from BALB/c was significantly less than that from CD-1 in response to co-culture with Bd. IFN-gamma production by CD-1 spleen cells in response to concanavalin A (Con A, 1microg/ml) was 8-fold greater than that by BALB/c spleen cells. In contrast, BAM and PM from BALB/c mice in co-culture with Bd secreted several-fold more TNFalpha than BAM or PM from CD-1 mice. IL-2 production by BALB/c spleen cells in response to Con A was 3- to 4-fold greater than that by CD-1 spleen cells. Depressed IL-2 production by Con A stimulated CD-1 spleen cells correlated with depressed proliferative responses. Resistance of CD-1 mice to pulmonary blastomycosis correlates with enhanced fungicidal activity of BAM, PM, PMN, and IFN-gamma production by Con A stimulated spleen cells, compared to BALB/c mice. Consistent with the in vitro enhancement of effector cell function by IFN-gamma, in vivo therapy with IFN-gamma significantly (P<0.0001) improved survival of BALB/c mice with pulmonary blastomycosis.     

4种小鼠的寒、热体质研究

[目的]研究4种品系小鼠的寒、热体质。[方法]8~9周龄昆明、BALB/c、C57BL/6J、ICR小鼠,以及4~5周龄昆明小鼠,同步系统检测其生物学特性,然后以统一的评价标准评价4种品系小鼠的寒、热体质。并对BALB/c小鼠给予参桂理中丸和利血平做药物反证。[结果]①4~5周龄昆明小鼠与8~9周龄昆明小鼠比较体质明显偏热;②BALB/c小鼠与C57BL/6J小鼠比较体质偏寒;③8~9周龄雄性BALB/c小鼠、雄性和雌性C57BL/6J小鼠与8~9周龄相应性别昆明小鼠比较体质无明显差异;8~9周龄雌性BALB/c小鼠与8~9周龄雌性昆明小鼠比较体质偏寒;④8~9周龄ICR小鼠与8~9周龄BALB/c小鼠、C57BL/6J小鼠比较体质偏热;8~9周龄雄性ICR小鼠与8~9周龄雄性昆明小鼠比较体质偏热。[结论]4种品系小鼠存在寒、热体质差异。     

Effect of the mitochondria-targeted antioxidant SkQ1 on development of spontaneous tumors in BALB/c mice

The mitochondria-targeted antioxidant SkQ1 (10-(6′-plastoquinonyldecyl)triphenylphosphonium) is a new pharmaceutical substance with a wide spectrum of effects including increase in lifespan of laboratory animals (for example, of BALB/c mice males) and inhibition of development of some experimental tumors and also of tumor cell growth. In this work, the effects of SkQ1 on development of spontaneous tumors in female and male BALB/c mice housed in an SPF-class vivarium were studied. We found that the addition of SkQ1 to drinking water at the dose of 1 and 30 nmol/kg body weight per day throughout the lifespan modified the spectrum of spontaneous tumors in the female mice, decreasing the incidence of follicular lymphomas. SkQ1 at the dose of 1 nmol/kg per day also suppressed the dissemination of these neoplasms, but it did not significantly influence the overall incidence of benign and malignant tumors (including primary multiple tumors) or the lifespan of the tumor-bearing mice (both males and females). Hence, the previously described ability of SkQ1 to increase the lifespan of laboratory BALB/c mice is not related to its anticarcinogenic activity.     

Age-related non-tumorous lesions in SPF C57BL/6 mice with special reference to amyloidosis]

Non-tumorous pathological changes in C57BL/6 CrSlc mice, which were reared under a barrier system and died spontaneously, were examined. At 3 months intervals 125 to 209 mice were purchased at 4 weeks of age and raised for the supply of aged animals. A large portion of the mice were used for various experiments between 3 and 30 months of age, while not a small number died spontaneously and were autopsied. The major non-neoplastic lesion was amyloidosis, with incidence of 55.5% and 74.4% for the autopsied female and male, respectively. The organs involved were the liver, kidneys, spleen, adrenal glands, ileum, heart and lungs. Skin ulceration and its scar, cerebral vascular calcification, glomerulosclerosis and sepsis in both sexes, distension of the seminal vesicles in males, fibroblast growth of the adrenal glands in females were commonly found. Incidence of spontaneous neoplastic lesions was 69.7% and 55.1% for the female and male, respectively.