RESUMEN
Variations among inbred rats in terms of anatomy and routine laboratory values can potentially blur surgical experimental results. Therefore, a retrospective analysis aiming at investigating hepatic and perihepatic anatomical variations, liver weight, body weight, liver weight/body weight ratio (LBWR), variations in routine laboratory values, and the influence of shipment and repeated sampling was performed. In our study, liver weight of rats seemed to be strain-specific. LBWR was weakly and negatively correlated with body weight in rats. A statistically significant difference in routine blood tests was found among normal rats grouped by different body weight or shipment. Weekly repeated sampling from the same rats revealed a statistically significant difference in a blood test. In conclusion, the fact that variation among rats or their environment can blur the results of a surgical experimental study should be kept in mind.
Asunto(s)
Variación Anatómica , Hígado/anatomía & histología , Ratas Endogámicas Lew/anatomía & histología , Animales , Recuento de Células Sanguíneas , Hígado/irrigación sanguínea , Trasplante de Hígado , Masculino , Tamaño de los Órganos , Ratas , Ratas Endogámicas Lew/sangre , Ratas Endogámicas Lew/cirugía , Valores de Referencia , Estudios RetrospectivosRESUMEN
OBJECTIVE: The majority of studies that involve behavioral testing in different rat strains is based on measuring behavioral responses to stressful situations in a novel environment. Very little is known on the spontaneous behavior in rat strains. The aim of the present study was to compare home cage behavior and basal hormone levels in two outbred rat strains, Sprague-Dawley (SD) and Wistar as well as two inbred strains, Lewis and Spontaneously Hypertensive Rats (SHR). METHODS: Twenty-eight male rats from four strains of rats (n=7/strain) were used in this study. Behavior of each rat in his home cage was recorded by a video camera for 45 minutes during the dark phase of the day. The parameters considered included rearing, jumps, ambulation, grooming, feeding/drinking and no movements. Blood plasma was analyzed for aldosterone, plasma renin activity (PRA), adrenocorticotropin hormone (ACTH) and corticosterone by specific radioimmunoassays. RESULTS: One-way ANOVA revealed significant inter-strain differences in counts of jumps and rearing. In comparison with Sprague-Dawley and Wistar rats, Lewis rats displayed significantly more jumps and rearing. Statistical analysis showed significant inter-strain differences in the levels of aldosterone and of plasma renin activity. The highest levels of aldosterone were found in Lewis rats. Plasma renin activity was significantly lower in SHR than in Sprague-Dawley rats. Correlation analysis failed to reveal any relationships between behavioral and endocrine parameters. Significant strain differences were observed also in relative weights of the spleen, adrenals and thymus. CONCLUSION: Plasma renin activity and basal mineralocorticoid secretion did not show parallel pattern if compared among different rat strains. Locomotor activity in the home cage, which could represent general activity to be considered in evaluating emotional responses, was highest in the Lewis rats.
Asunto(s)
Conducta Animal , Hormonas/sangre , Hormona Adrenocorticotrópica/sangre , Aldosterona/sangre , Animales , Peso Corporal , Masculino , Tamaño de los Órganos , Fotoperiodo , Ratas , Ratas Endogámicas Lew/sangre , Ratas Endogámicas Lew/psicología , Ratas Endogámicas SHR/sangre , Ratas Endogámicas SHR/psicología , Ratas Sprague-Dawley/sangre , Ratas Sprague-Dawley/psicología , Ratas Wistar/sangre , Ratas Wistar/psicología , Renina/sangreRESUMEN
The effect of mycophenolic acid (MPA) in combination with either cyclosporine (CsA) or tacrolimus (TRL) on whole-blood lymphocyte function was assessed in vitro as well as in vivo. For the in vitro studies, rat whole blood was incubated with different concentrations of MPA together with CsA or TRL. In vivo, rats (n = 6 per group) were orally treated with 2.5 or 5 mg/kg of mycophenolate mofetil (MMF), either alone or in combination with 5 mg/kg CsA or 4 mg/kg TRL. Blood was obtained before and at different times after dosing. For both in vitro and in vivo studies, mitogen-stimulated whole blood was analyzed by flow cytometry to determine inhibition of expression of lymphocyte proliferation (proliferating cell nuclear antigen, PCNA) and T-cell activation (eg, CD25). Plasma MPA concentrations were measured by HPLC, and whole-blood CsA and TRL concentrations were quantified using LC-MS/MS. In vitro, low concentrations of 250 and 500 nM MPA acted additively with CsA and overadditively with TRL to suppress lymphocyte function, whereas higher MPA concentrations (1000 nM) in these combinations did not further increase inhibition compared with monotherapy with CsA or TRL alone. In vivo, the MPA AUC0-24 showed a dose-dependent increase. CsA and TRL AUC0-24 were not influenced by the MMF dose. Combination therapy increased inhibition of lymphocyte function compared with MMF monotherapy with a pronounced effect on PCNA compared with CD25. Significant differences between 2.5 and 5 mg/kg MMF in the combination groups were observed at 2 or 6 hours after dosing because of the maximal inhibitory effect on PCNA and CD25 expression (P < 0.05, ANOVA). However, in combination with TRL no different effects on the inhibition of CD25 expression were found between the 2 MMF doses. These novel data indicate that measurement of pharmacodynamic parameters of lymphocyte function in whole blood may help to monitor drug combination therapy and provide a rationale for drug reduction to minimize toxicity without compromising efficacy.
Asunto(s)
Ciclosporina/farmacología , Linfocitos/efectos de los fármacos , Linfocitos/fisiología , Ácido Micofenólico/farmacología , Ratas Endogámicas Lew/sangre , Tacrolimus/farmacología , Administración Oral , Animales , Área Bajo la Curva , Proliferación Celular/efectos de los fármacos , Ciclosporina/sangre , Esquema de Medicación , Interacciones Farmacológicas , Quimioterapia Combinada , Hombres , Ácido Micofenólico/sangre , Ratas , Receptores de Interleucina-2/efectos de los fármacos , Receptores de Interleucina-2/genética , Tacrolimus/sangreRESUMEN
Insulin-dependent type 1 diabetes mellitus (IDDM) has been shown to alter the properties of bone and to impair fracture-healing in both humans and animals. The objective of this study was to examine changes in the histomorphometric and mechanical parameters of bone and remodeling during bone-defect healing, depending on the diabetic metabolic state in spontaneously diabetic BB/O(ttawa)K(arlsburg) rats, a rat strain that represents a close homology to IDDM in humans. A standardized bone-defect model was chosen and based on blood-glucose values at the time of surgery (mg%), postoperative blood-glucose course (mg%), and postoperative insulin requirements (IU/kg). A total of 120 spontaneously diabetic BB/OK rats were divided into groups with a well-compensated (n = 60; 169 +/- 102 mg%; 230 +/- 126 mg%; and 2.2 +/- 1.1 IU/ kg) or poorly compensated (n = 60; 380 +/- 159 mg%; 359 +/- 89 mg%; and 5.4 +/- 1.1 IU/kg) metabolic state. Sixty LEW.1A rats served as the normoglycemic controls (93 +/- 19 mg%). Fifteen animals from each group were killed on postoperative days 7, 14, 24, and 42, and specimens were processed undecalcified for quantitative bone histomorphometry and for biomechanical testing. Our study showed in terms of bone histomorphometry, within the first 14 days, that severe mineralization disorders occurred exclusively in the rats with a poorly compensated diabetic metabolic state with a highly significant (P < 0.001) or significant (P < 0.01) decrease of all fluorochrome-based parameters of mineralization, apposition, formation and timing of mineralization, as well as significantly decreased values of biomechanical properties (P < 0.05) in comparison to the spontaneously diabetic rats with a well-compensated metabolic state and to the control rats. Bone-defect healing in spontaneously diabetic BB/ OK rats is retarded exclusively in a poorly compensated diabetic metabolic state. This study suggests that strictly controlled insulin treatment resulting in a well-compensated diabetic metabolic state will ameliorate the impaired early and late parameters of IDDM bone-defect healing.
Asunto(s)
Fenómenos Biomecánicos , Glucemia/metabolismo , Diabetes Mellitus Tipo 1 , Fracturas del Fémur/tratamiento farmacológico , Curación de Fractura/efectos de los fármacos , Insulina/uso terapéutico , Animales , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 1/metabolismo , Modelos Animales de Enfermedad , Fracturas del Fémur/complicaciones , Fracturas del Fémur/metabolismo , Fémur/lesiones , Fémur/patología , Fémur/fisiopatología , Insulina/metabolismo , Ratas , Ratas Endogámicas BB , Ratas Endogámicas Lew/sangreRESUMEN
Lymphocytes play an important role in many lung diseases and are routinely accessible by bronchoalveolar lavage (BAL). Lymphocytes from the BAL (BAL pool) have a different subset composition to those from peripheral blood, consisting mainly of activated T-cells. The aim of this study was to examine whether preferential migration of activated T-cells to the bronchoalveolar space or factors of the specific microenvironment mediate this phenomenon. The expression of adhesion molecules and cellular activation markers (intercellular adhesion molecule-1, leukocyte function-associated antigen-1, CD2, CD44, interleukin-2 receptor and L-selectin) was studied on T- and B-cells not only in the BAL and peripheral blood (blood pool), but also in the compartments in between, such as the lung vascular perfusate (marginal pool) and the lung interstitium (interstitial pool), with the experiments being performed simultaneously in the same animals. Low levels of adhesion molecule expression were observed on T-cells in the blood and marginal pool, medium levels in the lung interstitium and the highest levels in the BAL. "Memory" (CD45R(low)) and "naive" (CD45R(high)) T-cells in the lung compartments showed a higher expression of adhesion molecules compared with blood. However, the predominating CD45R(low) T-cells showed a significantly higher expression than the CD45R(high) cells, indicating that CD4+ CD45R(high) T-cells had changed their phenotype to CD45R(low). In conclusion, a high level of expression of leukocyte function associated antigen-1 and intracellular adhesion molecule-1 on the bronchoalveolar lavage and interstitial T-cells is more likely to be the result of local, lung-specific induction than a prerequisite for migration into the bronchoalveolar space.
Asunto(s)
Moléculas de Adhesión Celular/biosíntesis , Linfocitos T/inmunología , Animales , Biomarcadores/análisis , Moléculas de Adhesión Celular/análisis , Pulmón/citología , Activación de Linfocitos , Masculino , Ratas , Ratas Endogámicas Lew/sangre , Linfocitos T/químicaRESUMEN
Indwelling catheters were implanted into the inferior vena cava of adult male and female Lewis/N and Fischer 344 rats. Each animal was exposed to ACTH, novelty stimulation, nicotine, lipopolysaccharide (LPS), and saline on 5 consecutive days. Blood was withdrawn before (baseline) and at several time points after the stimulus on each day. There were no differences in baseline corticosterone levels nor in responses to saline in any group. In general, responses to stimulation peaked at 15-30 min and returned to baseline by 60-90 min. Corticosterone responses to LPS showed a different time course; maximal responses occur at 1-2 h and return to baseline by 24 h. Fischer animals showed higher corticosterone levels than Lewis rats during the response to stimulation, but returned to baseline at the same times. Females of each strain showed higher corticosterone responses than males at 15, 30, and 45 min after ACTH, but the sexes did not differ in response to the other stimuli. For individual rats, the maximum response to ACTH was slightly correlated with the maximum response to novelty stimulation, nicotine, and saline but was not correlated with the response to LPS.
Asunto(s)
Corticosterona/sangre , Conducta Exploratoria/fisiología , Ratas Endogámicas F344/sangre , Ratas Endogámicas Lew/sangre , Hormona Adrenocorticotrópica/farmacología , Animales , Femenino , Lipopolisacáridos/farmacología , Masculino , Nicotina/farmacología , Ratas , Caracteres Sexuales , Cloruro de Sodio/farmacología , Factores de TiempoRESUMEN
Radiolabeled Borrelia burgdorferi, the etiologic agent of Lyme disease, injected intravenously into rats are cleared from the vasculature within 1 h of injection. One low passage isolate showed trafficking between the circulation and possibly the vessel walls for the first 2 h after injection. All strains used were resistant to the effects of normal and heat-inactivated rat serum. During the first 2 h after injection, B. burgdorferi can be visualized in, and recovered from, the platelet-rich plasma. B. burgdorferi can adhere to both human and rat platelets in in vitro assays, but an in vivo association with these cells was not apparent. Similarly, none of the strains of B. burgdorferi used induced platelet aggregation. Removal from the circulation into the organs was measured in perfused rats by polymerase chain reaction and autoradiography and in non-perfused rats by organ cultures. These organisms invade organs (heart, kidneys, bladder, liver, spleen, brain) within 1-6 h after injection. Invasion of organs occurred in an apparent random manner; a large amount of radiolabel but no live organisms was excreted in the urine during the first 24 h, suggesting degradation of the inoculum.
Asunto(s)
Sangre/microbiología , Grupo Borrelia Burgdorferi/aislamiento & purificación , Ratas/microbiología , Animales , Secuencia de Bases , Actividad Bactericida de la Sangre , Fenómenos Fisiológicos Sanguíneos , Plaquetas/microbiología , Encéfalo/microbiología , Femenino , Inyecciones Intravenosas , Masculino , Tasa de Depuración Metabólica , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Ratas/sangre , Ratas Endogámicas Lew/sangre , Ratas Endogámicas Lew/microbiología , Orina/microbiología , Vísceras/microbiologíaRESUMEN
The transfusion of blood is associated with long-term immunosuppression, which has been postulated to influence immunosurveillance and cancer cell killing. The mononuclear phagocyte synthesises large quantities of PGE2, and PGE2 has been shown to inhibit the activity of a range of immunocompetent cell types. The role of mononuclear phagocyte PGE2 synthesis in transfusion-associated immunosuppression, and the elements of transfused blood which control this immunosuppression, were investigated using a transfused rat model. A significant increase in macrophage PGE2 synthesis was detected 7 days after transfusion with blood and serum. The storage of blood for 24 h increased the stimulatory activity of transfused blood. The effects of storage and serum on macrophage PGE2 synthesis were greater than effects due to genetic differences between blood donor and recipient, and the serum effects indicated that a major factor activating PGE2-mediated immunosuppression in transfused subjects may be humoral in nature.
Asunto(s)
Transfusión Sanguínea , Dinoprostona/biosíntesis , Tolerancia Inmunológica/inmunología , Macrófagos/metabolismo , Animales , Formación de Anticuerpos , Conservación de la Sangre , Inmunidad Celular , Masculino , Cavidad Peritoneal/citología , Fagocitosis , Distribución Aleatoria , Ratas , Ratas Endogámicas Lew/sangre , Ratas Endogámicas Lew/inmunologíaRESUMEN
Four groups of inbred male LEW rats were examined: A, germfree athymic; B, specified pathogen free (SPF) athymic; C, germfree euthymic; D, SPF euthymic. All animals were killed at 18 weeks and compared with respect to body weight, histological appearance and cell density of the lymphoid organs, haematological values and differential counts of bone marrow, peripheral blood and lymph. Athymic rats had a lower body weight, less densely populated lymphoid organs, and fewer lymphocytes in the blood and lymph compared with euthymic animals. No difference was seen between athymic rats under germfree and SPF conditions, and in general the differences between athymic and euthymic animals were less pronounced under germfree conditions.
Asunto(s)
Células de la Médula Ósea , Vida Libre de Gérmenes , Linfa/citología , Tejido Linfoide/anatomía & histología , Ratas Endogámicas Lew/anatomía & histología , Ratas Endogámicas/anatomía & histología , Ratas Mutantes/anatomía & histología , Ratas Desnudas/anatomía & histología , Animales , Peso Corporal , Recuento de Leucocitos , Ganglios Linfáticos/anatomía & histología , Ganglios Linfáticos/citología , Linfocitos , Tejido Linfoide/citología , Masculino , Tamaño de los Órganos , Ratas , Ratas Endogámicas Lew/sangre , Ratas Desnudas/sangre , Organismos Libres de Patógenos Específicos , Bazo/anatomía & histología , Bazo/citología , Timo/anatomía & histología , Timo/citologíaRESUMEN
Platelet aggregation induced by ADP, arachidonic acid, and collagen was monitored in rats from two stocks, WSU-SD and CD, and from three strains, Lewis, Holtzman, and NBR. ADP-induced aggregation did not vary between the WSU-SD, CD, Lewis, Holtzman, and NBR rats. In contrast, the response to AA and collagen depended upon the stock or strain of rat. Platelets from the Holtzman and especially the NBR were much more sensitive to AA than were those from the other strains. At 0.25 mM AA, 7 of 8 NBR rats and 5 of 8 Holtzman rats aggregated irreversibly, while only 1 in 8 WSU-SD, CD, and Lewis rats aggregated irreversibly at that concentration. Collagen-induced aggregation reflected that to AA. The possible relationship between the variation in platelet aggregation and sympathoadrenal activity is discussed.
Asunto(s)
Agregación Plaquetaria/efectos de los fármacos , Ratas/sangre , Adenosina Difosfato/farmacología , Animales , Ácidos Araquidónicos/farmacología , Colágeno/farmacología , Ratas/genética , Ratas Endogámicas Lew/sangre , Ratas Endogámicas Lew/genética , Ratas Endogámicas/sangre , Ratas Endogámicas/genética , Valores de Referencia , Especificidad de la EspecieRESUMEN
Because of the difficulties in drawing blood for clinical chemistry in small laboratory animals there exist many methods for sampling blood and the preparation of serum, none of which is generally accepted or well standardised. It was the aim of this study to investigate the effects of sampling techniques on normal values of enzyme activities in the serum of rat and mouse. The activities of the following enzymes were determined: sorbitol dehydrogenase, lactate dehydrogenase, malate dehydrogenase, glutamate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, pyruvate kinase, creatine kinase, myokinase, alkaline phosphatase and leucine aminopeptidase. In addition plasmaproteins, urea and inorganic phosphorus were measured. In rats blood was obtained from the following sites: retroorbital venous plexus, jugular vein, heart and ventral aorta. In mice blood was sampled from the jugular vein and the ventral aorta. Shifts of water from the interstitial to the intravascular space due to hypovolemia occurring during the experimental procedure were followed up by measuring the hematocrit and the distribution of radioiodide labelled albumin. In rats the activities of lactate dehydrogenase, malate dehydrogenase, aspartate aminotransferase, pyruvate kinase, creatine kinase and myokinase found in blood serum obtained from the retroorbital venous plexus and the ventral aorta were too high compared to the other sampling sites. Activities of alkaline phosphatase and alanine aminotransferase were slightly elevated when blood was sampled from the punctured retroorbital venous plexus. Small differences in plasmaproteins and hematocrit values were found to be due to acute shifts of water within the extracellular space. In mice the activities of lactate dehydrogenase, malate dehydrogenase, aspartate aminotransferase and myokinase were found to be too high in blood serum obtained from the ventral aorta. Efflux of enzymes from damaged cells and the interstitial space ive caused erroneous results too, but only to a minor extent. The most reliable method for blood sampling in rat and mouse is the cannulation of the jugular vein. The heart puncture can be recommended too. Attention should be paid, however, to the possibility of aspirating disrupted muscle cells through the inserted needle.