Kinetics of ectromelia virus (mousepox) transmission and clinical response in C57BL/6j, BALB/cByj and AKR/J inbred mice

Research was undertaken to answer basic questions on susceptibility, clinical response and transmission of ectromelia virus in selected strains of inbred mice. C57BL/6J and AKR/J were found to be markedly more resistant to a virulent strain of ectromelia virus (isolated during the 1979-80 outbreak at the National Institutes of Health) than C57LJ, BALB/cByJ, DBA/2J, A.By/SNJ and C3H/HeJ when infected by footpad inoculation. In C57BL/6J and AKR/J the LD50 was about 7 logs higher than the ID50. With one exception, C57LJ, the LD50 and ID50 titers in the other strains were about equal. In C57LJ the LD50 titer was intermediate. Following intragastric inoculation, virus was isolated from feces of C57BL/6J mice for as long as 46 days and up to 29 days from BALB/cByJ mice. Transmission to cage mates from intragastrically infected C57BL/6J and BALB/cByJ occurred up to 36 and 30 days respectively after infection. Virus was isolated from the spleen in 2 of 5 BALB/cByJ mice and 1 of 7 C57BL/6J mice tested 95 days after gastric inoculation. Following footpad inoculation, BALB/cByJ mice consistently transmitted virus to cage mates before death at 10-12 days. C57BL/6J mice transmitted between days 8 and 17, but not beyond. Virus was maintained in C57BL/6J mice by exposure to infected cage mates for seven passages, which was the most attempted. Clinical signs in infected C57BL/6J mice were usually subtle or inapparent.     

Genetic determinants of resistance to ectromelia (mousepox) virus-induced mortality.

Resistance to ectromelia (mousepox) virus-induced mortality was examined in crosses between susceptible DBA/2J, A/J, and BALB/cByJ mice and resistant C57BL/6J and AKR/J mice. Depending on the cross, resistance to mousepox virus was shown to be determined by one or more independently assorting autosomal loci with dominant alleles for resistance in AKR/J and C57BL/6J mice and recessive alleles in A/J, BALB/cByJ, and DBA/2J mice. A sexual dimorphism in resistance to disease was also observed.     

Macronutrient diet selection in thirteen mouse strains

The strain distribution for macronutrient diet selection was described in 13 mouse strains (AKR/J, NZB/B1NJ, C57BL/6J, C57BL/6ByJ, DBA/2J, SPRET/Ei, CD-1, SJL/J, SWR/J, 129/J, BALB/cByJ, CAST/Ei, and A/J) with the use of a self-selection protocol in which separate carbohydrate, fat, and protein diets were simultaneously available for 26-30 days. Relative to carbohydrate, nine strains consumed significantly more calories from the fat diet; two strains consumed more calories from carbohydrate than from fat (BALB/cByJ, CAST/Ei). Diet selection by SWR/J mice was variable over time, resulting in a lack of preference. One strain (A/J) failed to adapt to the diet paradigm due to inadequate protein intake. Comparisons of proportional fat intake across strains revealed that fat selection/consumption ranged from 26 to 83% of total energy. AKR/J, NZB/B1NJ, and C67BL/6J mice self-selected the highest proportion of dietary fat, whereas the CAST/Ei and BALB/cByJ strains chose the lowest. Finally, epididymal fat depot weight was correlated with fat consumption. There were significant positive correlations in AKR/J and C57BL/6J mice, which are highly sensitive to dietary obesity. However, absolute fat intake was inversely correlated with epididymal fat in two of the lean strains: SWR/J and CAST/Ei. We hypothesize that the SWR/J and CAST/Ei strains are highly sensitive to a negative feedback signal generated by increasing body fat, but the AKR/J and C67BL/6J mice are not. The variation in dietary fat selection across inbred strains provides a tool for dissecting the complex genetics of this trait.     

Visual detection, pattern discrimination and visual acuity in 14 strains of mice

Based on the procedure of Prusky et al. (2000, Vision Research, 40, 2201-2209), we used a computer-based, two-alternative swim task to evaluate visual detection, pattern discrimination and visual acuity in 14 strains of mice from priority groups A and B of the JAX phenome project (129S1/SvImJ, A/J, AKR/J, BALB/cByJ, BALB/cJ, C3H/HeJ, C57BL/6J, CAST/Ei, DBA/2J, FVB/NJ, MOLF/Ei, SJL/J, SM/J and SPRET/Ei). Each mouse was tested for eight trials/day for 8 days on each of the three tests. There was a significant strain difference in visual ability in all three tests. Mice with reported normal vision (129S1/SvImJ, C57BL/6J and DBA/2J) and one albino strain (AKR/J) performed very well in these tasks. The other albino strains (A/J, BALB/cByJ and BALB/cJ) took longer to learn the tasks than mice with normal vision and did not reach the criterion of 70% correct. Mice with retinal degeneration (C3H/HeJ, FVB/NJ, MOLF/Ei and SJL/J) performed only at chance levels as did the three strains with unknown visual abilities (CAST/Ei, SM/J and SPRET/Ei). Because many behavioral tasks for rodents rely on visual cues, we suggest that the visual abilities of mice should be evaluated before they are tested in commonly used visuo-spatial learning and memory tasks.     

Hepatic triglyceride contents are genetically determined in mice: results of a strain survey

To assess whether genetic factor(s) determine liver triglyceride (TG) levels, a 10-mouse strain survey of liver TG contents was performed. Hepatic TG contents were highest in BALB/cByJ, medium in C57BL/6J, and lowest in SWR/J in both genders. Ninety and seventy-six percent of variance in hepatic TG in males and females, respectively, was due to strain (genetic) effects. To understand the physiological/biochemical basis for differences in hepatic TG among the three strains, studies were performed in males of the BALB/cByJ, C57BL/6J, and SWR/J strains. In vivo hepatic fatty acid (FA) synthesis rates and hepatic TG secretion rates ranked BALB/cByJ approximately C57BL/6J > SWR/J. Hepatic 1-(14)C-labeled palmitate oxidation rates and plasma beta-hydroxybutyrate concentrations ranked in reverse order: SWR/J > BALB/cByJ approximately C57BL/6J. After 14 h of fasting, plasma-free FA and hepatic TG contents rose most in BALB/cByJ and least in SWR/J. beta-Hydroxybutyrate concentrations rose least in BALB/cByJ and most in SWR/J. Adaptation to fasting was most effective in SWR/J and least in BALB/cByJ, perhaps because BALB/cByJ are known to be deficient in SCAD, a short-chain FA oxidizing enzyme. To assess the role of insulin action, glucose tolerance test (GTT) was performed. GTT-glucose levels ranked C57BL/6J > BALB/cByJ approximately SWR/J. Thus strain-dependent (genetic) factors play a major role in setting hepatic TG levels in mice. Processes such as FA production and hepatic export in VLDL on the one hand and FA oxidation on the other, explain some of the strain-related differences in hepatic TG contents. Additional factor(s) in the development of fatty liver in BALB/cByJ remain to be demonstrated.     

Estrous cycle effects on behavior of C57BL/6J and BALB/cByJ female mice: implications for phenotyping strategies

Systematic behavioral phenotyping of genetically modified mice is a powerful method with which to identify the molecular factors implicated in control of animal behavior, with potential relevance for research into neuropsychiatric disorders. A number of such disorders display sex differences, yet the use of female mice in phenotyping strategies has been a rare practice because of the potential variability related to the estrous cycle. We have now investigated the behavioral effects of the estrous cycle in a battery of behavioral tests in C57BL/6J and BALB/cByJ inbred strains of mice. Whereas the performance of BALB/cByJ female mice varied significantly depending on the phase of the estrous cycle in the open field, tail flick and tail suspension tests, the behavior of C57BL/6J females, with the exception of the tail suspension performance, remained stable across all four phases of the estrous cycle in all of the tests including open field, rotarod, startle reflex and pre-pulse inhibition, tail flick and hot plate. We also found that irrespective of the estrous cycle, the behavior of C57BL/6J females was different from that of BALB/cByJ groups in all of the behavioral paradigms. Such strain differences were previously reported in male comparisons, suggesting that the same inter-group differences can be revealed by studying female or male mice. In addition, strain differences were evident even for behaviors that were susceptible to estrous cycle modulations, although their detection might necessitate the constitution of large experimental groups.     

Acute locomotor responses to cocaine in adolescents vs. adults from four divergent inbred mouse strains

Growing evidence suggests that adolescent mice display differential sensitivity to the acute locomotor activating effects of cocaine as compared to adults, but the direction of the difference varies across studies and the reasons are not clear. Few studies have directly examined genetic contributions to age differences in locomotor stimulation from cocaine. The goal of this study was to determine the extent to which reduced stimulation in C57BL/6J adolescents as compared to adults generalizes to other strains. Therefore, we examined male and female mice from four genetically divergent inbred stains (BALB/cByJ, C57BL/6J, DBA/2J and FVB/NJ) at two ages, postnatal day 30 and postnatal day 65. Mice received either saline or cocaine (15 or 30 mg/kg), and then immediately were placed back into their home cages. Locomotor activity was recorded continuously in the home cage by video tracking. Adolescents displayed reduced stimulation as compared to adults for C57BL/6J, BALB/cByJ and female FVB/NJ mice. No age differences were observed for DBA/2J or male FVB/NJ. No main effects of sex were observed. Strain differences in pharmacokinetics, neural development or physiology could contribute to the observed differences between ages across strains. Future comparative studies could discover biological differences between strains that explain age differences in cocaine sensitivity.     

Comparison of urethane-induced sister-chromatid exchanges in various murine strains, and the effect of enzyme inducers

The induction of sister-chromatid exchanges (SCEs) by urethane, 150 and 300 mg/kg administered i.p., was examined in bone-marrow cells of AKR, BALB/c, C3Hf, C57BL/6J and DBA/2 male mice. In all strains, the base-line level of SCE/cell was similar, ranging from 4.3 to 8.7, and the response increased with the dose of urethane. DBA/2 mice were the most susceptible to urethane at both dose levels, with 30.6 SCE/cell after treatment with 300 mg/kg, whereas the response of the other strains was from 17.4 to 21.5 SCE/cell at the same urethane dose. Pretreatment of C57BL/6J and DBA/2 mice with phenobarbital decreased the SCE frequencies induced by urethane, 300 mg/kg, to 70%, whereas a prior administration of beta-naphthoflavone reduced SCE levels in C57BL/6J but not in DBA/2 mice.     

Francisella tularensis Vaccines Elicit Concurrent Protective T- and B-Cell Immune Responses in BALB/cByJ Mice

In the last decade several new vaccines against Francisella tularensis, which causes tularemia, have been characterized in animal models. Whereas many of these vaccine candidates showed promise, it remains critical to bridge the preclinical studies to human subjects, ideally by taking advantage of correlates of protection. By combining in vitro intramacrophage LVS replication with gene expression data through multivariate analysis, we previously identified and quantified correlative T cell immune responses that discriminate vaccines of different efficacy. Further, using C57BL/6J mice, we demonstrated that the relative levels of gene expression vary according to vaccination route and between cell types from different organs. Here, we extended our studies to the analysis of T cell functions of BALB/cByJ mice to evaluate whether our approach to identify correlates of protection also applies to a Th2 dominant mouse strain. BALB/cByJ mice had higher survival rates than C57BL/6J mice when they were immunized with suboptimal vaccines and challenged. However, splenocytes derived from differentially vaccinated BALB/cByJ mice controlled LVS intramacrophage replication in vitro in a pattern that reflected the hierarchy of protection observed in C57BL/6J mice. In addition, gene expression of selected potential correlates revealed similar patterns in splenocytes of BALB/cByJ and C57BL/6J mice. The different survival patterns were related to B cell functions, not necessarily to specific antibody production, which played an important protective role in BALB/cByJ mice when vaccinated with suboptimal vaccines. Our studies therefore demonstrate the range of mechanisms that operate in the most common mouse strains used for characterization of vaccines against F. tularensis, and illustrate the complexity necessary to define a comprehensive set of correlates.     

In vitro splenic T cell responses of diverse mouse genotypes after oronasal exposure to mouse hepatitis virus, strain JHM.

Mortality rates among BALB/cByJ, A/JCr, C3H/HeSnJ, and C57BL/6NCr mice inoculated oronasally with mouse hepatitis virus (MHV) strain JHM, ranged from 25 to 67%. Spleen cells harvested from the first three genotypes at 5 days postinoculation proliferated poorly in response to concanavalin A stimulation and produced significantly less interleukin (IL) 2 than cells from uninfected control mice. The function of spleen cells harvested at 14 days postinoculation varied and was host genotype-dependent. Despite clinical signs among some infected C57BL/6NCr mice, spleen cell function was relatively unaffected. C57BL/10ScNCr, B10.A, and SJL/JCr mice remained clinically normal after MHV inoculation. Proliferation and IL2 production by cells from inoculated C57BL/10ScNCr and B10.A mice were similar to responses of their respective controls. In contrast, cells from inoculated SJL/JCr mice were hyper-responsive and produced peak levels of IL2 earlier than control cells. Among the seven genotypes tested, only BALB/cByJ and C3H/HeSnJ spleen cells produced detectable IL4 after primary stimulation with concanavalin A or after priming and restimulation. Primary IL4 production by cells from these two genotypes was significantly reduced if donors were inoculated with MHV 5 days prior to spleen harvest. IL4 production by cells from acutely infected BALB/cByJ mice was considerably enhanced by priming and restimulation.     

Markers for predicting death as an outcome for mice used in infectious disease research

Our goal in this study was to identify objective criteria that could be used to predict an outcome of death in mice subjected to experimental inoculation with infectious organisms. We conducted a retrospective analysis of data collected from 4 independent studies that used several infectious agents (influenza virus strains A/HK/x31[H3N2] and A/Puerto Rico/8/34[H1N1], Streptococcus pneumoniae, and Candida albicans) and mouse strains (A/J, DBA/2J, C57BL/6J, BALB/cByJ). Postinoculation periods ranged from 5 to 21 d, with survival of 30% to 60% of the subjects. In all studies, mice were implanted with either a subcutaneous identification microchip or an intraabdominal radiofrequency transmitter to allow remote measurement of body temperature. After inoculation, mice were weighed and monitored regularly until death occurred or euthanasia was performed. Hypothermia was the most valuable characteristic for distinguishing mice that would survive or succumb to the infection. In addition, weight loss was useful in some of the models. In some cases, the derived measure of the product of temperature and body weight provided the best differentiation of mice in the 2 outcome categories. Therefore, the utility of these measures varied substantially depending on the specific model. This study demonstrates that specific endpoint markers are not uniformly applicable to different models. Rather, such markers should be developed and tested in the context of the model in which they will be used. The use of validated markers for eventual death can signal the need for preemptive euthanasia to alleviate terminal distress and permit timely collection of biologic samples.     

Fatal hemorrhagic diathesis associated with mild factor IX deficiency in pl/J mice

Surgical implantation of devices into the abdomen of PL/J mice was associated with fatal hemorrhage at 9 to 11 d after surgery. Coagulation profiles were evaluated to determine the underlying cause of this effect. The mean activated partial thromboplastin time (aPTT) of untreated PL/J mice was significantly higher than that of BALB/cByJ and C57BL/6J strains. The addition of human plasmas deficient in factors VIII, XI, or XII, prekallikrein, or high molecular-weight kininogen corrected the elevated aPTT of PL/J mice, but correction did not occur when factor IX-deficient human plasma was added. When compared to an assigned factor IX activity of 100% for pooled plasma from BALB/cByJ mice, C57BL/6J and PL/J mice revealed percent activities of 67% and 16%, respectively. PL/J mice could represent a new model for the study of pathogenesis and therapy of mild factor IX deficiency that is expressed and becomes clinically apparent secondary to major surgery.     

Lens density tracking in mice by Scheimpflug imaging

Scheimpflug imaging has recently been established for in vivo imaging of the anterior eye segment and quantitative determination of lens transparency in the mouse. This enables more effective investigations of cataract formation with the mouse model, including longitudinal studies. In order to enable recognition of disease-associated irregularities, we performed Scheimpflug measurements with the common laboratory inbred lines C57BL/6J, C3HeB/FeJ, FVB/NCrl, BALB/cByJ, and 129/SvJ in a period between 2 and 12 months of age. C57BL/6J mice showed lowest mean lens densities during the test period. Progressive cortical lens opacification was generally observed, with the earliest onset in C57BBL/6J, C3HeB/FeJ, and 129/SvJ, between 2 and 6 months after birth. Moreover, lenses of these inbred lines developed nuclear opacities. Calculated mean lens density significantly increased between 6 and 12 months of age in all inbred strains except 129/SvJ. Lens densities (and the corresponding standard deviations) of FVB/NCrl and 129/SvJ increased most likely because of differences in the genetic background. Albinism as confounder might be excluded since the albino Balb/cByJ mice are more similar to the C57BL/6J or C3Heb/FeJ mice. We further identified strain-specific anterior lens opacities (C57BL/6J) and cloudy corneal lesions (C57BL/6J, FVB/NCrl, and BALB/cByJ) at later stages. In conclusion, our results indicate that there are lifelong opacification processes in the mouse lens. The highest lens transparency and a dark coat color, which prevents interference from light reflections, make mice with the C57BL/6J background most suitable for cataract research by Scheimpflug imaging. We show that lens densitometry by Scheimpflug imaging in mouse eyes can resolve differences of less than 1 %, making it possible to detect differences in cataract development in different mouse strains, even if they are small.     

Deletion of self-reactive T cells in nude mice grafted with neonatal allogeneic thymus

The cellular basis of tolerance induction has been investigated in BALB/c(H-2d, thy 1.2, M1s1b2a) nude mice grafted with thymus of neonatal AKR/J mice(H-2k,Thy1.1,M1s1a2b). The spleen cells from nude mice grafted with AKR/J thymus showed a significantly decreased level of primary cytotoxic T cell response when stimulated with AKR/J cells, although these cells lysed well target cells of a third party C57BL/6 when stimulated with C57BL/6 cells. Consistent with CTL responses, T cells bearing V beta 6, that is important for recognizing M1s1a-encoded products of the thymic phenotype, were virtually abolished in the spleen and lymph node cells of nude mice 8 wk after grafting with AKR/J thymus. However, a substantial number of V beta 6-bearing T cells were detected in the peripheral organs of nude mice 23 wk after grafting with AKR/J thymus and in those of nude mice grafted with AKR/J fetal thymus depleted of macrophages/dendritic cells by incubating with 2'-deoxyguanosine in vitro before grafting. On the other hand, T cells bearing V beta 3, which are selectively related to M1s2a-encoded products of the host phenotype, were expressed neither on the peripheral T cells of nude mice grafted with AKR/J thymus at any stage after grafting nor on those of nude mice grafted with 2'-deoxyguanosine-treated AKR/J thymus. These data suggested that both V beta 6 and V beta 3 T cells were eliminated in the thymus of nude mice grafted with AKR/J thymus, presumably on the basis of interaction with both of graft-derived persisting and host-derived hemopoietic cells in the thymus and that thymic epithelium appears to have little capacity to eliminate T cells reactive to minor lymphocyte stimulating-encoded products.     

Relationship between genetic differentiation of the thymus in mice of different strains and malignant growth. IV. Genetic analysis of the thymic index in mice]

Relative thymus weight was estimated in C3H/He, C57BL/6 mice, their F1 and backcross hybrids, as well as in the progeny of complete diallel crosses between the BALB/c, C3H/He, C57BL/6 and AKR/J strains. On the basis of the analysis of these measurements, a conclusion is drawn that this character is inherited with incomplete dominance of smaller relative weight. The genes determining greater thymus weight are concentrated in the genetic pool of AKR/J and C57BL/6 strains. These genes are characterized by some degree of recessivity with respect to the genes determining smaller thymus weight which are concentrated in the genetic pool of C3H/He and BALB/c strains. The highest concentration of the "plus" and "minus" genes is found in the genetic pools of AKR/J and C3H/He strains respectively.     

NaCl taste thresholds in 13 inbred mouse strains

Molecular mechanisms of salty taste in mammals are not completely understood. We use genetic approaches to study these mechanisms. Previously, we developed a high-throughput procedure to measure NaCl taste thresholds, which involves conditioning mice to avoid LiCl and then examining avoidance of NaCl solutions presented in 48-h 2-bottle preference tests. Using this procedure, we measured NaCl taste thresholds of mice from 13 genealogically divergent inbred stains: 129P3/J, A/J, BALB/cByJ, C3H/HeJ, C57BL/6ByJ, C57BL/6J, CBA/J, CE/J, DBA/2J, FVB/NJ, NZB/BlNJ, PWK/PhJ, and SJL/J. We found substantial strain variation in NaCl taste thresholds: mice from the A/J and 129P3/J strains had high thresholds (were less sensitive), whereas mice from the BALB/cByJ, C57BL/6J, C57BL/6ByJ, CE/J, DBA/2J, NZB/BINJ, and SJL/J had low thresholds (were more sensitive). NaCl taste thresholds measured in this study did not significantly correlate with NaCl preferences or amiloride sensitivity of chorda tympani nerve responses to NaCl determined in the same strains in other studies. To examine whether strain differences in NaCl taste thresholds could have been affected by variation in learning ability or sensitivity to toxic effects of LiCl, we used the same method to measure citric acid taste thresholds in 4 inbred strains with large differences in NaCl taste thresholds but similar acid sensitivity in preference tests (129P3/J, A/J, C57BL/6J, and DBA/2J). Citric acid taste thresholds were similar in these 4 strains. This suggests that our technique measures taste quality-specific thresholds that are likely to represent differences in peripheral taste responsiveness. The strain differences in NaCl taste sensitivity found in this study provide a basis for genetic analysis of this phenotype.     

Dextran sulfate-induced peritoneal lysophospholipase activity varies among mouse strains

Lysophospholipase (LPL) activity resulting from the intraperitoneal injection of dextran sulfate (DS) was studied in different mouse strains. AKR/J and BALB/cByJ mouse strains showed decreased LPL levels when a low molecular weight DS was injected but increased LPL activity when high molecular weight DS was injected intraperitoneally. C57BL/6 mice had increased LPL activity with low molecular weight DS but decreased LPL activity with high molecular weight DS. All three mouse strains showed increased peritoneal-cell changes when injected with DS of a molecular weight of 79,000.This work was supported in part by Grants 80-12-215 and 81-04-008 from the American Osteopathic Association.     

Inhibition of nitric oxide synthesis increases mortality in Sindbis virus encephalitis.

Sindbis virus (SV) is an alphavirus that causes acute encephalomyelitis in mice. The outcome is determined by the strain of virus and by the age and genetic background of the host. The mortality rates after infection with NSV, a neurovirulent strain of SV, were as follows v: 81% (17 of 21) in BALB/cJ mice; 20% (4 of 20) in BALB/cByJ mice (P < 0.001); 100% in A/J, C57BL/6J, SJL, and DBA mice; and 79% (11 of 14) in immunodeficient scid/CB17 mice. Treatment with Nomega-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthetase (NOS) inhibitor, increased mortality to 100% (P < 0.05) in NSV-infected BALB/cJ mice, to 95% (P < 0.001) in BALB/cByJ mice, and to 100% in scid/CB17 mice. BALB/cJ and BALB/cByJ mice had similar levels of inducible NOS mRNA in their brains, which were not affected by L-NAME or NSV infection. Brain NOS activity was similar in BALB/cJ and BALB/cByJ mice before and after infection and was markedly inhibited by L-NAME. NSV replication in the brains of BALB/cJ mice, BALB/cByJ mice, and mice treated with L-NAME was similar. Treatment of N18 neuroblastoma cells with NO donors S-nitroso-N-acetylpenicillamine or sodium nitroprusside in vitro before infection increased cell viability at 42 to 48 h compared with untreated NSV-infected N18 cells with little effect on virus replication. These data suggest that NO protects mice from fatal encephalitis by a mechanism that does not directly involve the immune response or inhibition of virus growth but rather may enhance survival of the infected neuron until the immune response can control virus replication.     

Increased spontaneous polyclonal activation of B lymphocytes in mice with spontaneous autoimmune disease.

Early in life, mice of four kinds [NZB, (NZB X NZW)F1, MRL/1, and male BXSB] with autoimmune disease spontaneously produced far more (greater than 3 S.D.) anti-hapten antibody-forming cells in spleens and greater concentrations of anti-hapten antibodies in sera than immunologically normal strains of mice (AKR, BALB/c, C57BL/6, DBA/1-J, DBA/2J, LG/J, 129, NZW, and female BXSB). This increased nonspecific antibody production by the abnormal animals' B cells correlated well with the spontaneous development of anti-single-stranded DNA antibodies, but not with serum levels of the viral envelope glycoprotein, gp70. These results suggest that the spontaneous formation of autoantibodies in mice whose immunologic disorder is manifested by a lupus-like disease may result from polyclonal activation of B cells by endogenous or exogenous B cell activators.     

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。