Healthy Syrian Hamsters Research Articles

Results of selected ophthalmic diagnostic tests for clinically normal Syrian hamsters (Mesocricetus auratus).

To determine values for tear production, horizontal palpebral fissure length (HPFL), eye blink frequency, and intraocular pressure (IOP) in healthy Syrian hamsters (Mesocricetus auratus). 40 healthy adult Syrian hamsters (80 eyes). Tear production was measured with the phenol red thread test (PRTT), modified Schirmer tear test (mSTT), and endodontic absorbent paper points tear test (EAPPTT). The IOP was measured by use of rebound tonometry. Correlations between test results and body weight were evaluated. Mean ± SD values for the IOP, PRTT, EAPPTT, mSTT, HPFL, and blink frequency for all 80 eyes were 4.55 ± 1.33 mm Hg, 5.57 ± 1.51 mm/15 s, 4.52 ± 1.55 mm/min, 2.07 ± 0.97 mm/min, 5.84 ± 0.45 mm, and 1.68 ± 0.43 blinks/min, respectively. For all variables, values did not differ significantly between the right and left eyes or between males and females. There was no correlation between measured variables and body weight. Results for this study provided information on values for the IOP, PRTT, mSTT, EAPPTT, HPFL, and eye blink frequency in healthy Syrian hamsters. It was important to determine reference intervals for this species because they commonly are kept as pets or used as research animals.

Prevalence of intestinal parasites in hamsters and rabbits in some pet shops of Turkey.

In this study, we aimed to determine the parasite species carried by hamsters and rabbits purchased from some commercial pet shops in Turkey. For this purpose, the fecal samples of clinically healthy Syrian hamsters, dwarf hamsters, and crossbred rabbits were collected from 22 pet shops randomly selected in Ankara and Kirikkale provinces, located in Central Anatolia Region of Turkey. The fecal samples were examined with centrifuge flotation technique using saturated salt solution. Parasitic infection rate was 57.5% in dwarf hamsters, 54.9% in Syrian hamsters, and 56.3% in crossbreed rabbits. Trichurid eggs were the most prevalent parasite in the feces of Syrians hamsters (28.1%). The other parasites of Syrian hamsters were as follows: Eimeria spp. oocysts (15.4%) and the eggs of H. nana (11.2%), Syphacia spp. (11%). and Aspiculuris spp. (5.6 %). Only trichurid eggs were observed in the fecal samples of dwarf hamsters (51.5%). Oocysts of Eimeria spp. (52.7%) and the eggs of P. ambiguus (3.6%) were detected in the feces of rabbits. Within the scope of this study, the detection of H. nana eggs, a zoonotic parasite, in the feces of Syrian hamster was quite remarkable for public health.

Results of phenol red thread test in clinically normal Syrian hamsters (Mesocricetus auratus)

To determine the normal reference range for phenol red thread test (PRTT) values in clinically normal Syrian hamsters (Mesocricetus auratus). Sixteen healthy adult Syrian hamsters (eight males and eight females) were used in this study. Ophthalmic examinations were performed without chemical restraint. PRTT values were evaluated in both eyes of all Syrian hamsters using a commercial PRTT strip of a single lot number. No statistically significant differences between right and left eyes were found for any of the results. The mean ± SD PRTT values for the study population were 6.8 ± 2.5 mm/15 s with a range from 3 to 11.5 mm/15 s. Mean PRTTs in male animals were 5.1 ± 1.2 mm/15 s, whereas mean PRTTs in female hamsters were 8.5 ± 2.3 mm/15 s. Comparison between mean PRTT values in males and females showed a significant difference (P = 0.004). Mean weights for males and females were 80.9 ± 4.8 and 90.6 ± 8.5 g, respectively. No linear relationship between mean PRTT and body weight was found in female (P = 0.46) and male (P = 0.92) hamsters. This study provides novel data for normal reference ranges of PRTT values in healthy Syrian hamsters. Results of this study may assist veterinarians in the diagnosis of ocular surface disease and syndromes affecting the tear film in these species.

Syrian Golden hamster - A model forExamining Metabolic Effects of Volitional Training.

1747 The Syrian Golden hamster is commonly used as a model of dietary induced insulin resistance. Fat metabolism in hamsters closely resembles that in humans and this animal is known to exercise voluntarily. PURPOSE: To explore the metabolic effects of volitional training on young, healthy Syrian hamsters. METHODS: Male, 24- day old, hamsters with initial weight of 46.6 ± 0.83g (mean ± SEM), were randomly divided into sedentary (n = 8) and trained (n = 8) groups. The training group had 24-hour access to running wheels over 4 weeks of study. Food consumption, body weight and running distance were recorded daily and blood glucose was measured once per week. Non-fasted animals were euthanized by decapitation under CO2 anaesthesia and blood and tissues were collected for analysis. Plasma leptin, insulin, GLP-1, glucagon and amylin concentrations were measured in 10ul of serum using a Rat/Mouse Endocrine Panel (Linco Research, Inc.). RESULTS: The distance ran increased during the training period from 12.8 ± 1.11km/day at week 1 to 20.3 ± 0.82km/day at week 4. By the second week, food consumption was significantly higher (p<0.01) in trained (9.6 ± 0.2g/day) than in sedentary (6.48 ± 0.13g/day) animals. Although both groups gained weight, there was no difference in body mass between groups at any time point. Right visceral fat pad was larger (p<0.001) in sedentary (0.72 ± 0.04g) than in trained (0.24 ± 0.02g) animals. There was no difference in the blood glucose over the duration of the study between the trained and sedentary controls (4.6 ± 0.08mM/L vs 4.8 ± 0.1mM/L respectively). Leptin levels in sedentary hamsters were higher (p<0.05) than in trained hamsters (92.2 ± 15.7pM vs 35.5 ± 6.17pM, respectively). No significant difference was seen between the trained and sedentary animals in plasma insulin (284 ± 50.6pM vs 291.6 ± 49.7pM) nor GLP-1 (14.57 ± 3.9pM vs 10.93 ± 1.4pM) levels. Plasma glucagon and amylin were not detectible in sufficient animals to allow for comparison between groups. CONCLUSION: Our observations reveal that the extremely high volume of exercise exhibited by the animals, as well as their metabolic profile, may make this animal model particularly useful for the study of physiological effects of heavy endurance type training on metabolism.

Syrian Golden hamster - A model forExamining Metabolic Effects of Volitional Training.

1747 The Syrian Golden hamster is commonly used as a model of dietary induced insulin resistance. Fat metabolism in hamsters closely resembles that in humans and this animal is known to exercise voluntarily. PURPOSE: To explore the metabolic effects of volitional training on young, healthy Syrian hamsters. METHODS: Male, 24- day old, hamsters with initial weight of 46.6 ± 0.83g (mean ± SEM), were randomly divided into sedentary (n = 8) and trained (n = 8) groups. The training group had 24-hour access to running wheels over 4 weeks of study. Food consumption, body weight and running distance were recorded daily and blood glucose was measured once per week. Non-fasted animals were euthanized by decapitation under CO2 anaesthesia and blood and tissues were collected for analysis. Plasma leptin, insulin, GLP-1, glucagon and amylin concentrations were measured in 10ul of serum using a Rat/Mouse Endocrine Panel (Linco Research, Inc.). RESULTS: The distance ran increased during the training period from 12.8 ± 1.11km/day at week 1 to 20.3 ± 0.82km/day at week 4. By the second week, food consumption was significantly higher (p<0.01) in trained (9.6 ± 0.2g/day) than in sedentary (6.48 ± 0.13g/day) animals. Although both groups gained weight, there was no difference in body mass between groups at any time point. Right visceral fat pad was larger (p<0.001) in sedentary (0.72 ± 0.04g) than in trained (0.24 ± 0.02g) animals. There was no difference in the blood glucose over the duration of the study between the trained and sedentary controls (4.6 ± 0.08mM/L vs 4.8 ± 0.1mM/L respectively). Leptin levels in sedentary hamsters were higher (p<0.05) than in trained hamsters (92.2 ± 15.7pM vs 35.5 ± 6.17pM, respectively). No significant difference was seen between the trained and sedentary animals in plasma insulin (284 ± 50.6pM vs 291.6 ± 49.7pM) nor GLP-1 (14.57 ± 3.9pM vs 10.93 ± 1.4pM) levels. Plasma glucagon and amylin were not detectible in sufficient animals to allow for comparison between groups. CONCLUSION: Our observations reveal that the extremely high volume of exercise exhibited by the animals, as well as their metabolic profile, may make this animal model particularly useful for the study of physiological effects of heavy endurance type training on metabolism.

Insulin deficiency and reduced expression of lipogenic enzymes in cardiomyopathic hamster

Evidence is given that the heart of the cardiomyopathic UM-X7.1 hamster has a lipid composition different from that of the same tissue isolated from animals of the Syrian hamster parent strain. Also, noncardiac tissues from cardiomyopathic and healthy hamsters exhibit significant compositional differences. On the basis of these preliminary observations, a comparative study of the hepatic biosynthesis of lipids in cardiomyopathic and healthy Syrian hamsters was undertaken. The results obtained indicate that the cardiomyopathic hamster is characterized by a generalized disturbance of lipid metabolism. In particular, the fatty acid synthase and stearoyl-CoA desaturase activities were significantly lower in the liver of UM-X7.1 hamsters than in age-matched healthy controls fed the same diet. Northern blot analysis of the mRNAs encoding the two enzymatic proteins and the “lipogenic” S14 nuclear protein indicated that the transcription of the respective genes was impaired in UM-X7.1. Short-term dietary manipulations modulated the expression of the above-mentioned genes both in cardiomyopathic and healthy animals. However, dietary carbohydrates were less effective in inducing the expression of lipogenic enzymes in UM-X7.1 liver than healthy controls. The main determinant of the metabolic defect pointed out in the present work appears to be represented by the low insulin level detectable in the plasma of the cardiomyopathic hamster.—Vecchini, A., L. Binaglia, M. Bibeau, M. Minieri, F. Carotenuto, and P. Di Nardo. Insulin deficiency and reduced expression of lipogenic enzymes in cardiomyopathic hamster. J. Lipid Res. 2001. 42: 96–105.

Efficiency of β-adrenoceptor subtype coupling to cardiac adenylyl cyclase in cardiomyopathic and control hamsters

Densities of β-adrenoceptor subtypes and their contributions to stimulation of adenylyl cyclase were studied in heart ventricles from cardiomyopathic (BIO 8262) and control Syrian hamsters (CLAC) at 4 different ages: 30, 100, 200 and 300 days. In BIO ventricles neither total β-adrenoceptor density nor that of the β 1-adrenoceptor subtype differed from the controls, whereas the density of β 2-adrenoceptors was significantly higher in myocardium from 200- and 300-day-old BIO compared to that from age-matched CLAC hamsters. Stimulation of adenylyl cyclase by the non-selective β-adrenoceptor agonist isoprenaline did not differ between strains, but the β 1-adrenoceptor mediated component was significantly reduced in cardiomyopathic hamsters of all age groups. In 300-day-old animals β 1-adrenoceptors accounted for 83% (CLAC) and 68% (BIO) of total β-adrenoceptor binding sites, whereas only 26% (CLAC) and 6% (BIO) of the isoprenaline effect on cAMP formation were mediated via β 1-adrenoceptors. Thus, the present study shows a lower coupling efficiency of β 1-adrenoceptors compared to the β 2-adrenoceptor subtype in ventricles from healthy Syrian hamsters and a progressive, further reduction in β 1-adrenergic function in cardiomyopathic animals.

Isolation of a Campylobacter-like organism from healthy Syrian hamsters (Mesocricetus auratus).

A Campylobacter-like organism was isolated from the ilea of normal hamsters. The organism was isolated from an ileal homogenate which was passed through a filter (0.65-micron pore size) and cultured on blood-agar plates in a microaerophilic atmosphere at 37 degrees C. Pinpoint translucent colonies were first observed after 120 h of incubation. The isolated organism measured 2.0 to 3.5 microns in length (excluding flagella) by 0.17 to 0.25 micron in width and typically had a single terminal sheathed flagellum. The organism was oxidase, catalase, and urease positive, reduced nitrates, and was susceptible to nalidixic acid (30-micrograms disk) and resistant to cephalothin (30-micrograms disk). Unlike Campylobacter pylori subsp. mustelae, this organism did not hydrolyze indoxylacetate. Immunofluorescence studies with a Campylobacter species-specific monoclonal antibody (8322-2E6) revealed the presence of numerous positively stained organisms within the crypt epithelial cells of the hamsters from which this organism was isolated. The role of this organism in the pathogenesis of proliferative ileitis in hamsters is uncertain, as is the taxonomic relationship of this organism to other members of the genus Campylobacter.

Increases responsiveness to stimulation of α- but not β-adrenoceptors in the hereditary cardiomyopathy of the Syrian hamster. Intact adenosine- and cholinoceptor-mediated isoprenaline antagonistic effect

The effects of phenylephrine (in the presence of propranolol) or isoprenaline and of adenosine or carbachol (alone and in the presence of isoprenaline) were studied on the force of contraction in electrically driven papillary muscles isolated from the hearts of cardiomyopathic (strain BIO 8262) and age-matched, healthy Syrian hamsters. All experiments were performed in the so-called prenecrotic stage of the disorder within the first 30 days of life. Phenylephrine exerted a positive inotropic effect in all preparations from the cardiomyopathic hamsters. In contrast, in thirteen preparations from healthy Syrian hamsters, phenylephrine increased force of contraction in only four preparations. The positive inotropic effect of isoprenaline was similar in both cardiomyopathic and healthy Syrian hamsters. Adenosine and carbachol apparently reduced the isoprenaline-induced increase in force of contraction in both cardiomyopathic and healthy Syrian hamsters. We conclude that an increased responsiveness to α-adrenergic stimulation occurs in the hearts of cardiomyopathic Syrian hamsters and may be related to the myocardial injury occuring in this syndrome. An increased responsiveness to β-adrenoceptor stimulation or an impaired adenosine-mediated or cholinoceptor-mediated feedback inhibition is unlikely to play a role in the aetiology of this syndrome.

Shapes and sizes of synaptic vesicles in the cerebellum of the Syrian hamster‐cortex and deep nuclei

AbstractMaterial was obtained from eight adult apparently healthy Syrian hamsters perfused with 3.2% glutaraldehyde in phosphate buffer. Cortex and deep nuclei were prepared for electron microscopy by osmication and Epon embedding. Measurement of size and shape of vesicles was from printx × 50,000. Vesicle profiles whose least diameter was 75% or more of the maximum diameter were classified as round (spherical). If the greatest dimension was more than twice the least, the vesicle was termed flattened, all others oval. So defined, the synaptic sacs in the deep nuclei, large sacs of the granular layer and small sacs of the molecular layer contained more round vesicles than oval and flat combined and differences between these three locations were slight. In large sacs of the molecular layer, oval and flattened vesicles slightly outnumbered round ones. Average sizes were deep nuclei 468 Å, large sacs of granular layer 494 Å, small sacs of molecular layer 452 Å and large sacs of molecular layer 414 Å. Statistical analysis indicated that the mean size of vesicles was significantly different when each of the four locations was compared with the others. These differences are too small to be apparent by inspection. Since the vesicles in the deep nuclei are intermediate in size between those in mossy terminals and the axospinous ones of the molecular layer it was concluded that size and shape of vesicles did not distinguish between excitatory and inhibitory synapses in Syrian hamster cerebellum.