无菌豚鼠与普通豚鼠血液学参数的比较

目的对普通级豚鼠进行剖宫产,培育无菌豚鼠模型,并比较无菌豚鼠和普通级豚鼠的血液学参数。方法行子宫摘除术摘除子宫,在无菌隔离器中将子宫剥离取仔,用人工哺乳的方法将仔豚鼠培育成无菌豚鼠,并在固定的周期检测豚鼠的无菌情况。采用全血细胞计数分析仪、全自动血液生化分析仪测定无菌豚鼠、普通豚鼠的血常规和血生化参数。用SPSS12.0进行统计分析。结果无菌豚鼠和普通豚鼠在白细胞(WBC)、嗜碱性粒细胞数(BA#)、单核细胞百分比(MO)、血红蛋白浓度(MCHC)、中性粒细胞数(NE#)、嗜酸性粒细胞数(EO#)、淋巴细胞数(LY#)七个血常规指标上有差异显著性,其他指标没有显著性差异;谷丙转氨酶(ALT)、乳酸脱氢酶(LDH)、总蛋白(TP)、白蛋白(ALB)、葡萄糖(GLU)、总胆固醇(CHO)、总胆红素(TBIL)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、甘油三酯(TG)、球蛋白(GLO)、A/G、K、Na、谷酰转肽酶(GGT)15个指标上差异有显著性,其他指标差异无显著性。结论通过规范的子宫摘除术和人工喂养的方法获得符合标准的无菌豚鼠,与普通豚鼠在多项血液学指标上差异有显著性。     

Ascorbic acid catabolism by gut microflora: studies in germ-free and conventional guinea pigs

The role of gut microflora in ascorbic acid catabolism was investigated in both conventional and germ-free guinea pigs. In vitro studies demonstrated extensive degradation of the vitamin by fresh feces, cecal, and colonic contents of conventional guinea pigs. Direct injection of [1-¹⁴C] ascorbic acid into the cecum of conventional guinea pigs in vivo yielded a 70% recovery of the label as respiratory ¹⁴CO₂ within 6 hr compared with only 5% recovery following injection into the virtually sterile peritoneum in a comparable group of conventional guinea pigs. Thus, ascorbic acid not absorbed prior to reaching the lower gastrointestinal tract stands to be extensively decarboxylated by microflora in the cecum. In a companion study of germ-free guinea pigs, 10% of an administered dose of [1-¹⁴C] ascorbic acid was expired as ¹⁴CO₂ within 36 hr post-injection following intraperitoneal injection compared with 16% recovery in a matched group of conventional animals injected at the same site. Results of this series of studies suggest that hepatic decarboxylation and gut microflora, in tandem, contribute to ascorbic acid decarboxylation in this species.     

Antigen-induced suppression of mitogen responses and resistance to experimental autoimmune encephalomyelitis

Random-bred Hartley and inbred Strain 2 and Strain 13 guinea pigs were inoculated for acute experimental autoimmune encephalomyelitis (EAE). Sixty-six percent (69/103) of the Hartleys developed signs of EAE while the remaining 34% (34/103) were resistant. No Strain 2 and all Strain 13 guinea pigs developed EAE. Histologic examination of nervous tissue revealed that susceptible Hartleys and Strain 13 and Strain 2 animals had lesions characteristic of EAE. Tissue from resistant Hartleys showed fewer and less severe changes. Lymphocyte-transformation assays with EAE-inducing and noninducing antigens and T-cell mitogens revealed three different sets of responses in vitro: (i) lymphocytes from all animals responded to mitogens; (ii) lymphocytes from susceptible animals responded to EAE-inducing antigens; and (iii) lymphocytes from resistant Hartleys were suppressed from responding to the mitogens solely by EAE-inducing antigens. Plasmas from all EAE-sensitized animals had equivalent anti-myelin basic proteins (MBP) antibody titers and skin tests of EAE-inoculated Hartleys were all positive for MBP sensitization. Therefore, resistance and reduced histologic changes characteristic of EAE correlated with a disease-specific antigen-induced suppression of lymphocyte responses to T-cell mitogens. This suggests that clinical resistance to EAE in Hartley guinea pigs is mediated by an immunologic suppressor mechanism.     

Microbiological monitoring of Guinea pigs reared conventionally at two breeding facilities in Korea.

In this study, microbiological monitoring of guinea pigs reared conventionally in two facilities was performed twice in 2004, with a three-month-interval between surveys. This study was based on the recommendations of the FELASA Working Group, with some modifications. In serological tests in the first survey, some animals from facility A showed positive results for Encephalitozoon cuniculi, Sendai virus, pneumonia virus of mice (PVM), and Reovirus-3 (Reo-3); facility B showed a positive result only for E. cuniculi. The results of the second survey were similar to the first, except for the presence of Sendai virus; all animals from the two facilities were Sendai virus-negative in the second experiment. No pathogenic bacteria were cultured in the organs of any of the animals in the first survey. However, in the second survey, Bordetella bronchiseptica was cultured from the lung tissue of two 10-week-old animals from facility A. Chlamydial infection was examined by the Macchiavello method, but no animal showed positive results. Tests using fecal flotation or the KOH wet mount method showed no infection of endoparasites, protozoa, ectoparasites, or dermatophytes in any animal in both surveys. However, in the histopathological examination, an infection of protozoa-like organisms was observed in the cecum of some animals from facility A. The present study revealed that microbiological contamination was present in guinea pigs reared conventionally in two facilities in Korea, suggesting that there is a need to improve environmental conditions in order to eradicate microbial contamination.     

Bronchoalveolar eosinophilia in guinea pigs harboring inapparent infections of Paraspidodera uncinata

During the course of experiments examining the changes in cell populations in bronchoalveolar lavage (BAL) fluid in 3-11-wk-old guinea pigs, a marked increase in the numbers of eosinophils was observed in BAL fluid in untreated control animals from historical levels (observations made over the previous 2 yr) of 8.8 +/- 1.5% to levels greater than 16% and up to 44%. Repeated occurrence of this phenomenon in several different groups of guinea pigs that appeared clinically normal and the impact on our experimental studies led us to attempt to identify the cause of increased inflammatory cell numbers in these guinea pigs. Examination in 2 groups of animals of whole blood and lung tissue for the presence of bacteria or fungi revealed minor bacterial infections in one group but not the other, whereas both exhibited elevated eosinophil numbers. At necropsy, 41.7% and 60% of the animals in the 2 groups harbored the nematode Paraspidodera uncinata. Guinea pigs exhibiting eosinophil numbers in BAL fluid comparable to our historical levels were then inoculated with approximately 100 embryonated eggs of P. uncinata and developed elevated eosinophilia in BAL fluid compared to sham-inoculated animals (significant at 2 of the 3 examination times postinoculation). These findings suggest that P. uncinata is capable of causing changes in inflammatory cell populations in the lungs of guinea pigs and illustrate the importance of subclinical or inapparent infections in experimental design and interpretation.     

Effect of the normal microbial flora on the resistance of the small intestine to infection

Abrams, Gerald D. (The University of Michigan Medical School, Ann Arbor), and Jane E. Bishop. Effect of the normal microbial flora on the resistance of the small intestine to infection. J. Bacteriol. 92:1604-1608. 1966.-Mucosal structure in the small intestine is known to be influenced by the normal microbial flora. This suggests that mucosal resistance to invasion by enteric pathogens might also be affected by the flora. To assess this possibility, germ-free and conventional mice were challenged with Salmonella typhimurium, and both the growth of organisms within the intestinal lumen and the translocation to mesenteric lymph nodes were studied quantitatively. There were significantly more organisms 24 hr after intragastric challenge in the mesenteric nodes of germ-free animals than in those of conventional ones. However, since intraluminal growth in the intestine was also greater in germ-free animals, no conclusion could be drawn about mucosal resistance per se. Results were similar when the challenge was intraduodenal. However, when intestinal emptying was prevented by ileal ligation before challenge, both intraluminal growth and translocation of S. typhimurium were equal in the two groups of mice. It is concluded from these data, as well as from preliminary dye studies of intestinal motility, that the normal flora does not influence mucosal resistance directly, but may alter enteric infection by affecting intestinal emptying.     

Pathomorphological and immunofluorescent studies of smallpox vaccine neurotropism]

Experiments were conducted on guinea pigs sensitized with the AK C-vaccine components. In intracardiac injection with smallpox vaccine there was shown a possibility of development of marked hemodynamic disturbances, of the inflammatory-dystrophic processes of irreversibel character, with a subsequent neuronophagia and demyelinization. Injection of smallpox vaccine into the circulation of intact guinea pigs was accompanied by development in the nervous system of insignificant circulatory disturbances and of the inflammatory dystrophic phenomena of reversible character. A method of immunofluorescence was used and the antigen of the vaccine virus was revealed in the neurons of the brain and the spinal cord of the sensitized and intact animals. Marked hemodynamic and insignificant inflammatory-dystrophic processes were revealed in the nervous system of a child which died of the post-vaccinal encephalitis; an antigen of the smallpox virus was found by the immunofluorescent method in the nerve cells and the vessels in various portions of the nervous system.     

Study of the nature of toxic factors in burns on sterile guinea pigs]

Experiments were conducted on sterile and contaminated guinea pigs. The toxicity of the serum and the water-salt extracts of the internal organs after the burn was studied by the action on the leukocyte migration in a culture. Despite the complete absence of the microbial flora, the toxic properties of the serum and of the extracts of the internal organs of the sterile animals were the same as in the contaminated organs. The data obtained pointed to the important role of the histiogenic factors in the development of burn intoxication.     

Effects of the Human Intestinal Flora on Germ-free Mice

The effects of complete human intestinal flora and of intestinal anaerobes on germ-free mice were studied. The gross composition of the flora of mice was similar to that of the flora with which the animals had been contaminated and appeared to be stable provided that the animals were kept isolated. The complete flora and the anaerobes reduced caecal weight to normal values and induced an antagonistic effect against Escherichia coli. In contrast to the complete flora, the anaerobes were not invasive in immunosuppressed mice and induced colonization resistance and antagonism against Pseudomonas aeruginosa.     

Angiostrongylus cantonensis: Development following pulmonary arterial transfers into permissive and nonpermissive hosts

The survival, growth, and egg-laying capacity of young adult Angiostrongylus cantonensis, surgically transferred from intracranial sites into pulmonary arteries, were studied. A variety of experimental animals (rats, guinea pigs, mice, and mastomys) were chosen as donor animals and as recipient hosts (rats, guinea pigs, and rabbits). These species were specifically chosen to span the spectrum of host permissiveness relative to worm development in an attempt to understand the mechanisms which underlie species-dependent resistance. Recipient animals were monitored not only for the development of parasites per se but also for antibody production and histopathologic changes. The results indicated that these procedures were technically feasible, with good worm development following intra-rat transfers, as early as 15 days after initial exposure. Studies were performed to analyze the constraints of development both on initial, i.e., prelung and subsequent i.e., postlung development. When worms were obtained from permissive species such as rat or mastomys, transfer into rats resulted in good growth and development; however, worms which developed initially in exposed mice or guinea pigs developed less well in the rat. Conversely, worms which developed initially in permissive host such as the rat, when transferred into a variety of less permissive hosts such as the guinea pig and rabbit, apparently did not survive and caused significant morbidity and mortality within the nonpermissive host. Histopathologic evaluation revealed a strong eosinophilic perivascular and peribronchiolar infiltration as well as granulomatous reactions surrounding the worms in the lungs of recipient guinea pigs and rabbits, changes not observed in the lungs of permissive rat recipients. As reaginic antibody responses were also more prominent in nonpermissive than in permissive animals, it is possible that IgE responses may be more directly related to the phenomenon of morbidity and/or permissiveness than are other aspects of immune response. In support of this contention was the finding of nearly equivalent hemagglutinating antibody production between permissive rats and nonpermissive guinea pigs and rabbits.     

Giardiasis in guinea pigs: a case report

During the quarantine of 15 guinea pigs acquired from a breeder in February 1983, several became weak and moribund, and one died. A tremendous number of Giardia sp. bodies were detected from stamp smear preparations of the duodenal contents of some necropsied animals in this group. Histopathological examinations of the intestine revealed slight inflammatory changes and cystic enlargement of the crypts in the duodenal and jejunal mucous membranes. From these findings and the fact that other major pathogenic organisms were not detected, this disease was diagnosed as giardiasis in guinea pigs.     

Toxicity and proteolysis in gnotobiotic rats with thermal burns]

Experiments were conducted on germ-free (gnotobiotic) rats. A study was made of the toxic properties of the organs and the activity of proteolytic enzymes in them after thermal burns. Despite the absence of pathogenic microbial flora the germ-free rats developed the state of toxemia with an increase of the level of proteolytic enzymes. The extent of the toxic and catabolic reaction depended on the severity of the burn. Intoxication and an increase in proteolysis in the gnotobiotic rats were similar, and, in a number of cases greater than in usual animals. A conclusion was drawn on the important role of the tissue sources of intoxication in burns. A correlation between the toxemia and proteolysis was established.     

Guinea pig model of Mycobacterium tuberculosis latent/dormant infection

Although guinea pigs are considered one of the best animal models of tuberculosis, little data exist describing latent or dormant tuberculosis infection in these animals. Here we address this issue using a streptomycin auxotrophic mutant of Mycobacterium tuberculosis. This mutant grows unimpaired in the presence of streptomycin but in its absence shifts to latency/dormancy (lack growth and over-expression of alpha-crystallin). To establish infection animals are inoculated with the mutant followed by daily administration of streptomycin (three weeks), which allows initial microbial multiplication in the animal's tissues. Withdrawal of streptomycin establishes latency/dormancy and few viable organisms are recovered from the animals' lungs and spleen six months later. During the infectious process guinea pigs steadily gained weight and presented no clinical signs (scuff fur and lethargy) of disease. Histopathology of organs mimicked tuberculous lesions in humans and PBMC from infected animals strongly responded to stimulation with PPD. Finally, tuberculin skin test (a hallmark of latent infection diagnosis) performed in infected animals was strongly positive (>or=15 mm induration). These results point to an interesting and reliable model of latent/dormant tuberculosis infection in guinea pigs.     

Local Shwartzman phenomenon in germ-free guinea pig]

Eleven germfree and two monoassociated with the Citrobacter guinea pigs, and 25 conventional animals were injected with the heat-inactivated Citrobacter or E. coli for the induction of the local Schwartzman phenomenon. All the gnotobiotic pigs gave a positive reaction. Infiltration at the site of intracutaneous injection was found in all the conventionals, but in none of the gnotobiotics. The data are discussed from the aspect of primary and secondary sequelae of the absence of host microflora.     

Decreased extracellular matrix production in scurvy involves a humoral factor other than ascorbate

Our recent studies suggested that decreased collagen synthesis in bone and cartilage of scorbutic guinea pigs was not related to ascorbate-dependent proline hydroxylation. The decrease paralleled scurvy-induced weight loss and reduced proteoglycan synthesis. Those results led us to propose that the effects of ascorbate deficiency on extracellular matrix synthesis were caused by changes in humoral factors similar to those that occur in fasting. Here we present evidence for this proposal. Exposure of chick embryo chondrocytes to scorbutic guinea pig serum, in the presence of ascorbate, led to effects on extracellular matrix synthesis similar to those seen in scorbutic animals. The rates of collagen and proteoglycan synthesis were reduced to approximately 30-50% of the levels in cells cultured in normal guinea pig serum plus ascorbate, but proline hydroxylation and procollagen secretion were unaffected. Similar results were obtained with serum from fasted guinea pigs supplemented in vivo with ascorbate. The growth rate of the chondrocytes was not significantly affected by scorbutic guinea pig serum.     

Responder strain-specific enhancement of endothelial and mononuclear cell Ia in delayed hypersensitivity reactions in (strain 2 X strain 13)F1 guinea pigs

This study was undertaken to test the hypothesis that preferential responder strain-specific Ia expression can be detected in delayed hypersensitivity (DH) skin reactions. Seven adult (strain 2 X strain 13)F1 and two strain 13 guinea pigs were sensitized with poly-L glutamic acid-lysine (GL), poly-L glutamic acid-tyrosine (GT), and bovine insulin in complete Freund's adjuvant, and were skin tested with GL, GT, PPD, bovine insulin, porcine insulin (which has the same B chain as bovine insulin), and saline. Strain 2 guinea pigs react with bovine insulin A chain, GL, and PPD but not with GT or the bovine insulin B chain, whereas strain 13 guinea pigs react with bovine insulin B chain, GT, and PPD but not with GL or bovine insulin A chain. The (2 X 13)F1 animals had positive DH responses to GT, GL, PPD, and bovine insulin. At 24 hr, areas of induration were measured and the test sites and draining lymph nodes were biopsied. Cryostat sections were stained with monoclonal antibodies to strain 2 Ia, strain 13 Ia, and Ia framework determinants with immunoperoxidase. Stained dermal and subdermal inflammatory cells and vessels were counted on coded slides. In GT tests, there was more staining of dermal and subdermal cells and vessels for strain 13 Ia than strain 2 Ia (p less than 0.02). In bovine insulin tests there was more staining of dermal cells and vessels for strain 13 than strain 2 Ia (p less than 0.05). In GL tests there was more staining on dermal vessels and subdermal cells and vessels of strain 2 Ia than strain 13 Ia (p less than 0.05). There was much greater staining of strain 2 Ia of dermal cells and vessels in GL tests compared with strain 2 Ia staining in GT and bovine insulin tests (p less than 0.02, cells; p less than 0.01, vessels). No significant differences between strain 2 and strain 13 Ia expression were found in PPD, porcine insulin tests, saline controls, or in lymph nodes that drained sensitization sites from animals in which GL and GT had been injected on different sides. Anti-Ia framework expression generally correlated with the greater parental strain Ia in each reaction. These findings and previous observations in experimental allergic encephalomyelitis suggest that responder type Ia may be selectively found in vivo on mononuclear and endothelial cells in sites of T cell-mediated hypersensitivity reactions.     

Hypersensitivity of the delayed type in immunization and infection with Mycoplasma pneumoniae]

In parenteral and intranasal immunization with M. pneumoniae of guinea pigs, along with seroconversion, there was observed development from the 15th-20th day of hypersensitivity of delayed type; this hypersensitivity was revealed by positive skin tests and by the reaction of specific transformation of the peripheral blood lymphocytes. An increased reactivity of the smooth muscles of the intestine of parenterally immunized animals was revealed. With the aid of the test of alteration of blood neutrophils in vitro there was found development of specific sensitization of the organism to M. pneumoniae in the patients with mycoplasma pneumonia.     

Electron microscope studies of experimentalEntamoeba histolytica infection in the guinea pig

Early cellular and vascular changes in response to invasion of lamina propria byEntamoeba histolytica were studied sequentially, at the ultrastructural level, in germfree guinea pigs inoculated intracecally with amebae and enteric flora derived from patients with acute amebic colitis. Approximately one week post-inoculation the animals developed acute colitis with mucosal invasion by trophic amebae. Although epithelial cells at the sites of amebic invasion showed progressive cytoplasmic changes and desquamation resulting in microerosions, most mesenchymal elements in the lamina propria appeared normal without cytopathic changes even when in direct contact with invading amebae. Only the polymorpho-nuclear leukocytes (PMN) apposed or topographically close to amebae exhibited degenerative changes which were characterized by condensation of nucleoplasm and cytoplasm, extracellular release of cytoplasmic components including granules, and, finally, lysis of cell membranes. Capillaries and venules in the lamina propria showed a variety of changes such as swelling and gap formation at the intercellular endothelial junctions and more rarely at the fenestrae. Blood vessels physically close to amebae showed formation of endothelial cytoplasmic blebs which pinched off into the vascular or extravascular space. Platelet and fibrin thromboses were common in the more severely damaged capillaries and venules. Fragments or clumps of fibrin-like material were found also in the extracellular spaces. Amebic invasion of the lamina propria, then, is accompanied by continued epithelial shedding, PMN degeneration, and changes in both capillaries and venules consisting of endothelial damage and occlusive thrombosis. The vascular changes appeared to be closely related to PMN degeneration resulting from interaction of PMN with invading amebae.     

Routes of E. coli 055 bacterial penetration through the intestinal wall in gnotobiotic and ordinary animals]

Peculiarities of permeability of intestinal barrier in germfree animals for enteropathogenic E. coli 055 were studied. Both germfree and conventional guinea pigs and rats were used. An increase of bacteriemia was revealed in gnotobiotes during the first day of oral E. coli 055 monocontamination; bacteriemia was transient in conventional animals. Under electron microscopy alterations of intercellular contacts and formation of spaces between enterocytes containing numerous microorganisms were found in the intestinal mucous membrane in gnotobiotes. Also more pronounced changes of microvessels of the intestinal mucous membrane were discovered in gnotobiotes. The processes of ingestionan and digestion of Escherichia coli by enterocytes and leukocytes were noted in conventional animals. The revealed derangements of the intestinal barrier in gnotobiotes explain the cause of higher bacteriemia in germfree animals. An important role of the microbial factor in the formation of intestinal barrier is indicated by the data obtained.     

Toluene diisocyanate-induced airway hyperreactivity in guinea pigs depleted of granulocytes

The influence of cyclophosphamide-induced granulocyte depletion on toluene diisocyanate (TDI)-related changes in airway reactivity and pathology was assessed in guinea pigs. Twelve cyclophosphamide-treated and 12 control animals comprising each group were studied physiologically before and 2 h after a single 10-min exposure to 3 ppm of TDI. Reactivity was determined in intact unanesthetized animals by measuring specific airway conductance before and during intravenous acetylcholine infusion. After testing, tracheal tissue for light microscopic examination was obtained from three hyperreactive guinea pigs in each exposed group and compared with tissue from treated and control animals (n = 3 each) that had not been TDI exposed. Cyclophosphamide treatment caused substantial decreases in both circulating and airway granulocyte counts. However, the incidence and degree of bronchial hyperreactivity that occurred 2 h post-TDI was similar in the untreated and treated groups. Our results indicate that TDI-induced bronchial hyperreactivity 1) occurs shortly after a brief high concentration exposure and 2) appears independent of circulating or airway granulocyte counts.