Osteosarcomas in BALB/c female mice

Osteosarcomas were found in 16 of 24,192 (0.066%) BALB/c female mice, 14 were in 21,816 (0.064%) 2-acetylaminofluorene-treated mice, and two were in 2,376 (0.084%) untreated controls. The osteosarcomas were classified into osteoblastic, fibroblastic, and mixed types. Seven of the osteosarcomas metastasized to the lungs. The osteosarcomas in control and 2-acetylaminofluorene-treated mice showed little or no difference in the incidence, type, size, or site of origin, indicating that 2-acetylaminofluorene did not affect the development of osteosarcomas in BALB/c female mice.U     

Spontaneous heart failure in BALB/c mice

The hearts of BALB/c mice are known to acquire pronounced greyish white spots (cardiac white spots). BALB/c male mice were examined for the relationship between the incidence of cardiac white spots and weekly age, and compared with DDY male mice. During the observation period of 0.4-30 weeks, cardiac white spots on the right ventricle of BALB/c mice were first detected at three weeks (6 of 20 mice; 30%), and the maximal incidence of cardiac white spots was obtained at nine weeks (39 of 44 mice; 88%). In contrast, DDY mice were completely devoid of cardiac spots. Histopathologically, the cardiac spots were dystrophic calcinosis. There were significant increases in the relative organ weights of the heart and kidney of BALB/c mice compared with those of DDY mice. However, there was no significant difference between BALB/c and DDY mice in serum calcium concentration or histological characteristics of the parathyroid gland or bone marrow. The cardiac white spots of BALB/c mice were considered to be controlled by genetic susceptibility that occurred spontaneously with aging. The results described here suggest that BALB/c mice are adequate experimental animals for the study of myocardial disease that occurs spontaneously.     

Passage of hybridomas in male BALB/c mice

For cultivating hybridomas in the ascitic form there are usually used female mice BALB/c and not male ones. Efficiency of production of monoclonal antibodies with cultivation of the hybridomas in male and female mice BALB/c was studied comparatively. The animals were stimulated to form ascite by administration of the incomplete Freund's adjuvant or 3 per cent peptone with petrolatum oil. Some parameters of the ascite formation were studied: viability of the hybridoma cells, ascitic fluid formation period and volume, hybridoma cell concentration and titers of monoclonal antibodies in the ascitic fluid. In regard to all the parameters studied the male animals were not inferior to the female ones and in case of one of the hybridomas even surpassed them twofold by the volume of the ascitic fluid formed. This is evident of possible using male mice for mass cultivation of hybridoma cells with a purpose of obtaining preparative amounts of monoclonal antibodies in production of immunodiagnostic agents on their basis.     

Safety evaluation of Bifidobacterium pseudocatenulatum G4 as assessed in BALB/c mice

AIMS: To assess the safety of Bifidobacterium pseudocatenulatum G4 in BALB/c mice that involves examination of bacterial translocation, changes in the internal organs and histology of the intestinal lining. METHODS AND RESULTS: Forty male BALB/c mice were randomly assigned into five groups (n = 8). Three groups were orally fed with 50 microl of three different concentrations of B. pseudocatenulatum G4 (2 x 10(4), 1 x 10(8) and 1 x 10(11) CFU day(-1)) for 4 weeks. One group was orally administered with 50 microl of 1 x 10(8) CFU B. longum BB536 per day for 4 weeks and last group was used as a nonbifidobacterial treatment control, which received 50 microl of skim milk. The administered strains did not affect the general health of mice and incapable of carrying out translocation to blood or liver. There were no significant differences in the internal organ (liver, heart, kidney and spleen) indices, serum enzymes of liver (aspartate aminotransferase, alkaline phosphate, alanine aminotransferase) and kidney (urea and creatinine) and histology (villi height, crypts height, mucosa thickness and epithelial cell height) of caecum, ileum and colon. CONCLUSION: Administration of high dose of up to 1 x 10(11) CFU B. pseudocatenulatum G4 per day to mice did not show any health threatening symptoms. SIGNIFICANCE AND IMPACT OF THE STUDY: Bifidobacterium pseudocatenulatum G4 is none pathogenic to BALB/c mice and could be safe probiotic for human consumption.     

猪圆环病毒3型感染BALB/c小鼠的实验观察

目的研究猪圆环病毒3型(porcine circovirus3,PCV3)对BALB/c小鼠的感染情况。方法将雌性BALB/c小鼠分为两组,实验组感染PCV3组织毒,对照组接种同样剂量的PBS。感染后每天观察小鼠状态,并在第0,3,7,11和14天采血进行荧光定量PCR检测和ELISA检测。实验结束后,对所有动物进行安乐死和剖检,对心脏、肝、脾、肺、肾、脑和淋巴结取样进行荧光定量PCR检测,并制片进行组织病理学检查。选择PCR检测阳性组织进行PCV3CAP基因测序分析。结果PCV3组织毒感染小鼠不引起明显的临床症状和病理变化。病毒可在感染早期的血清中检测到,病毒含量最高的器官是肝脏和脾脏,PCV3感染小鼠后核酸序列未发生变化。随着感染时间的增加血清中抗体水平逐渐升高。结论PCV3可以感染BALB/c小鼠,并在小鼠体内增殖。本研究结果为猪圆环病毒3型致病性的研究以及防控提供了参考。     

Bacteriology of the oral cavity of BALB/c mice

To be used as a model in dental research, an animal must fulfil experimental needs and information on the composition and variation of its oral flora must be available. Only limited data are available on the indigenous oral bacterial flora of BALB/c mice. In this work, a total of 671 isolates from different sites (saliva, tongue, teeth, and mucosa) of the oral cavity of BALB/c mice were identified. Only 18 different species were isolated, which indicates the relative simplicity of the flora. The predominant species of the total cultivable flora were "Lactobacillus murinus" (38%), Staphylococcus aureus (37%), Streptococcus faecalis (8%), Staphylococcus sciuri (4%), and Escherichia coli (3%). The other species each represent less than 2% of the flora. "Lactobacillus murinus" is found in greater proportion on mucosa than in the other sites, Staph. aureus predominates in saliva, and Strep. faecalis was found in greater proportion in tooth samples. Statistical analyses, using the minimum percentage of similarity, indicate that there is some variation among the microflora of different mice but that this difference is smaller for mice from the same lot. These results set the basis for the study of the variations of the indigenous oral microflora of BALB/c mice under different conditions.     

双歧杆菌增强小鼠机体的免疫功能

【目的】本研究针对实验室自行从内蒙传统发酵乳制品中分离得到的两株双歧杆菌Bifidobacterium adolescentis BB-2和B.longum BB-3,对其调节机体免疫的功能进行了评价。【方法】采用健康SPF级BALB/c小鼠,每组10只,空白组灌胃无菌脱脂乳,阳性对照组灌胃含有商业菌株BB-12的无菌脱脂乳,处理组同样以无菌脱脂乳为溶液,灌胃含有不同剂量的Bifidobacterium adolescenti BB-2或B.longum BB-3,测定细胞免疫(迟发型变态反应DTH、脾淋巴细胞增殖MTT显色反应、自然杀伤细胞活性),体液免疫(绵羊红细胞免疫后的血清溶血素活性),以及非特异性免疫(巨噬细胞吞噬活性)指标。【结果】表明BB-2和BB-3两株双歧杆菌均能够增强DTH反应。双歧杆菌组小鼠的巨噬细胞的吞噬活性也有提高,同时自然杀伤细胞活性及血清溶血素水平也高于对照组,菌株处理组的脾淋巴细胞增殖率也有提高。剂量效应不显著,其中低剂量浓度(102-6cfu/m L)即可发挥作用。【结论】证明双歧杆菌BB-2和BB-3能够促进小鼠先天性免疫力和获得性免疫力的提高。本研究的开展对开发我国具有自主产权的功能菌株具有重要意义。     

Ultrastructural and cytoarchitectural features of lymphoreticular organs in the colon and rectum of adult BALB/c mice

The structure and function of colonic mucosal lymphoid organs remain largely unexplored, especially in the rectum hidden within the pelvic vault. Two-month-old female BALB/c mice were anesthetized, and the entire colon was removed from cecum to anus. Distal colonic patches were then prepared for electron microscopy or were quick-frozen and sectioned for immunoperoxidase localization of B cells and T cell subsets. Aggregated lymphoid follicles were distributed irregularly along the entire colon with an average of 1.4 patches per centimeter of colon length. There were large collections of follicles opposite the ileocecal valve (cecal patches), variable numbers of patches throughout the colon, and at least one patch within 10 mm of the anus (rectal patch). Follicles were adjacent to branching crypts lined by epithelium infiltrated by lymphoid cells and containing few goblet cells. In electron micrographs, M cells were identified by their short, irregular microvilli; intraepithelial lymphoid cells; reduced lysosomal dense bodies; and an expanded tubulovesicular network. Small germinal centers were seen. Cytoarchitectural components of colonic lymphoid follicles and Peyer's patch follicles were remarkably similar, despite differences in surrounding mucosa and luminal microbial exposure. The presence of organized lymphoid tissue with M cells and germinal centers suggests that transepithelial particle transport and antigen recognition can take place in the rectum. Whether such tissue has the capacity for uptake of luminal microorganisms is of particular interest, not only because colonic follicles may be sites for local initiation of immune responses but also because they may be important entry points for systemic infection.     

Gastrointestinal microecology of BALB/c nude mice.

The aerobic, facultative, and anaerobic microorganisms cultivable from the stomachs, ilea, ceca, and colons of BALB/c athymic (nu/nu) mice (normal and wasting), thymus-implanted normal nude mice, and their heterozygous (nu/+) littermates were investigated. Ninety-one species representing 23 genera of bacteria and yeasts were isolated from the 27 mice. The wasting nude mice showed significantly lower numbers of lactobacilli in their stomach microbiota than did mice from the other three groups. The littermate animals appeared unique among the four groups in having corynebacteria as a major constituent of their stomach and ileal flora. The normal nude mice appeared to have a more diverse anaerobic stomach flora than their heterozygous littermates. These minor differences are discussed with respect to possible immunological, physiological, and environmental factors as their cause. Because the gastrointestinal microfloras of the mice from the four groups were not radically divergent from each other, it was concluded that loss of T-cell function does not dramatically alter the makeup of the cultivable gastrointestinal microflora in these mice.     

The frequency of para-azophenylarsonate and dimethylaminonapthalene-sulfonyl-specific B cells in neonatal and adult BALB/c mice.

The limiting cell dilution splenic focus technique has been used to determine the frequency of p-azophenylarsonate (Ars) and 5-dimethylaminonaphthalene-sulfonyl (Dansyl)-specific B cells in neonatal and adult mice. The adult frequencies for Ars and Dansyl in conventionally reared BALB/c mice are 1.5 +/- 0.3/10(5) B cells and 9.4 +/- 3.3/10(5) Bcells, respectively. Dansyl-specific precursor cells are present in high frequencies at birth and reach adult precursor frequency levels during the first week of life. This finding mirrors the ontogenetic development previously described fro dinitrophenyl (DNP) and trinitrophenyl (TNP), but contrasts with the results obtained fro fluorescein (FL) and phosphorylcholine (PC), for which precursors arise later in development. On the other hand, the kinetics of appearance of B cells specific for Ars is unique in that the precursor frequency appears to decrease during the first week of life. The data presented remain consistent with a highly ordered, rigorously predetermined acquisition of the specificity repertoire during ontogeny. By increasing the flexibility of the splenic focus technique to allow analysis of other, chemically diverse haptens, results have been obtained that confirm and extend observations made with DNP, TNP, FL, and PC.     

Angiostrongylus cantonensis activates inflammasomes in meningoencephalitic BALB/c mice

Angiostrongylus cantonensis is a metastrongyloid nematode that causes eosinophilic meningoencephalitis in humans. A high infestation of A. cantonensis can cause permanent brain damage or even death. The inflammasome is an oligomeric molecular platform that can detect microbial pathogens and activate inflammatory cytokines. The recognition of larval surface antigens by pattern recognition receptors (PRRs) can cause oligomerization of the NOD-like receptor (NLR) or absent in melanoma 2 (AIM2) with the adaptor apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) to form a caspase-1-activating scaffold. Activated caspase-1 converts pro-inflammatory cytokines into their mature, active forms. Helminths infection has been shown to activate NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasomes. In this study, we aimed to investigate the mechanism of inflammasome activation upon A. cantonensis infection in a mouse model. This study provides evidence that A. cantonensis infection can activate NLRP1B and NLRC4 inflammasomes and promote pyroptosis to cause meningoencephalitis.     

Diversity of the Tcra-V3 gene family in BALB/c mice

 Southern analysis of Eco RI-digested BALB/c liver DNA reveals four T-cell receptor Tcra-V3-hybridizing DNA fragments, which are of sizes 18.0, 12.0, 8.0, and 2.1 kilobases, respectively. These four Tcra-V3-hybridizing genomic DNA were isolated from a BALB/c genomic library. Restriction and Southern analysis of the genomic DNA clones showed that each of the Tcra-V3-hybridizing Eco RI DNA fragments harbors only a single Tcra-V3 gene. The DNA sequences of coding regions of the four Tcra-V3 family members were determined. These sequences show very limited divergence from one another. Comparisons of BALB/c Tcra-V3 sequences with published Tcra-V3 sequences expressed in different strains of mice reveal substantial allelic polymorphism. Sequence similarity searches retrieved homologous rat, cattle, and human genes. The scarcity of coding sequence divergence among members of the Tcra-V3 family and the more substantial allelic polymorphism may be general features of the T-cell receptor V-alpha chain-encoding gene families. Received: 11 April 1996 / Revised: 26 May 1996     

Study on the ophthalmic diseases in ICR mice and BALB/c mice.

In pharmaceutical companies and research institutes, many toxicity tests are performed with laboratory animals. This study was performed to produce reference data for eye toxicity tests and to investigate the ophthalmic diseases of 408 ICR mice and 119 BALB/c mice, which are commonly used as subjects in toxicity tests. The experimental animals without clinical disorders were selected regardless of sex. The ophthalmic diseases were examined by using special ophthalmic instruments: direct ophthalmoscope, indirect ophthalmoscope, slit-lamp biomicroscope and focal illuminator. The most prevalent ocular variation within normal limits was hyaloid vessel remnant (ICR mice, 28.2%; BALB/c mice, 31.9%) and the incidence gradually decreased with age. The ocular diseases found in ICR mice were retinal degeneration (9.8%), corneal scar (4.2%), focal cataract (2.2%), anisocoria (1.2%), corneal ulcer (0.2%) and uveitis (0.2%). In BALB/c mice, corneal scar (9.2%), focal cataract (1.7%) and corneal ulcer (0.8%) were the ocular diseases found.     

Combined effect of nicotinamide and streptozotocin on diabetic status in partially pancreatectomized adult BALB/c mice.

Pancreatic regeneration after pancreatectomy has been well documented in the animal models. We have recently reported that STZ diabetic animals operated for partial pancreatectomy showed normoglycemic status after the operation as compared to uncontrolled hyperglycemia and even death in the diabetic sham operated animals. In drug and virus-induced experimental diabetic models there is a high mortality of animals due to uncontrolled destruction of the beta-cells. In order to destroy sufficient beta-cell mass so as to induce diabetes but prevent mortality, we designed present studies to investigate the combined effect of pancreatectomy, nicotinamide, and streptozotocin (STZ) on diabetic status of BALB/c mice. BALB/c mice of either sex were subjected to 50% pancreatectomy. These were then treated with nicotinamide (350 mg/kg body weight) before and after streptozotocin (200 mg/kg body weight) administration. The changes in body weight, blood glucose levels, serum and pancreatic insulin contents of these animals were monitored in experimental and control group for 12 weeks, and follow up studies were made of these animals for further 12 weeks. It was found that there was a drastic loss of body weight, decreased serum and pancreatic insulin levels coupled with sustained and low levels of hyperglycemia in the experimental group as opposed to the control group. The results indicate that partial pancreatectomy followed by nicotinamide and streptozotocin treatment leads to a long-lasting hyperglycemic state, depicting the clinical symptom of NIDDM without mortality. The study probably reveals a new model for experimental diabetes.     

博尔纳病病毒对BALB/c小鼠感染性检测

目的分析博尔纳病病毒（Borna disease virus,BDV）H1766株对BALB/c小鼠的感染性。方法选择病毒滴度为2.0×107FFU/ml的BDV病毒液分别对新生和成年BALB/c小鼠进行脑内接种,并用相同病毒液对原代培养的新生BALB/c小鼠脑细胞进行接种。经过一定时间的病毒作用后分别提取总RNA,采用巢式RT-PCR方法检测BDV-p40基因,并通过免疫组化方法检测脑内接种脑组织中BDV-P40蛋白。结果脑内接种病毒的小鼠脑组织中可以检测到BDV-p40基因和BDV-P40蛋白,培养的小鼠脑细胞中可以检测到BDV-p40基因。结论BDVH1766株可以感染新生和成年的BALB/c小鼠。     

Hydrogen protects mice from radiation induced thymic lymphoma in BALB/c mice

Ionizing radiation (IR) is a well-known carcinogen, however the mechanism of radiation induced thymic lymphoma is not well known. Moreover, an easy and effective method to protect mice from radiation induced thymic lymphoma is still unknown. Hydrogen, or H(2), is seldom regarded as an important agent in medical usage, especially as a therapeutic gas. Here in this study, we found that H(2) protects mice from radiation induced thymic lymphoma in BALB/c mice.     

Study of a mtDNA deletion in BALB/c mice exposed to ionizing radiation

A novel large mtDNA deletion of 5914 bp was detected in mice exposed to X-radiation. The regions flanking the deleted fragment were characterized by the method of sequencing. The possibility of using a minimum sample of the mouse auricle tissue for detecting mtDNA deletions in the same animals at different postradiation times is demonstrated.