Characteristics of the Germfree Rat

Gordon, Helmut A.; Bruckner-Kardoss, Edith; Staley, T. E.; Wagner, M.; Wostmann, Bernard S.

doi:10.1159/000142843

Cited by 63 publications

(35 citation statements)

References 2 publications

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“…Furthermore, in adrenalelectromiced rats, Bastl et al (1992) have demonstrated that aldosterone and glucocorticoid had an antagonistic effect on sodium transport in the rat colon. Further indications of an increased plasma-aldosterone concentration in GF rats are a reduced urine flow, a high urine concentration (Lev et al, 1970) and heavier adrenals (Gordon et al, 1966).…”

Section: Electrical Measurementsmentioning

confidence: 99%

Sodium transport across the caecal and colonic epithelium of germfree and specific-pathogen free rats

Rösel¹,

Engelhardt²

1996

Reprod. Nutr. Dev.

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Summary ― It was assumed that the enlarged caecum and the accumulation of semiliquid contents in germfree rats is accompanied by changes in sodium absorption. Transepithelial sodium fluxes were studied under Ussing chamber conditions across epithelial sheets of the caecum and colon of germfree (GF) and specific-pathogen free (SPF) rats. Net sodium transport was highest in the proximal colon and in the proximal segment of the distal colon; it was considerably lower in the caecum and in the distal segment of the distal colon. In the caecum and proximal colon of the GF rats, the electroneutral sodium absorption was increased as compared to the SPF rats. In the proximal segments of the distal colon, no differences were seen. In the distal segment of the distal colon, the mainly electroneutral sodium transport in the SPF rats was changed into electrogenic transport in the GF rats. These differences may be due to the increased aldosterone levels of the GF rats.germfree / specific-pathogen free / rat / caecum / colon / sodium transport / in vitro Résumé -Transport du sodium à travers l'épithélium caecal et colique chez des rats axéniques ou sans germes pathogènes. L'hypothèse initiale du présent travail était que des modifications de l'absorption du sodium accompagnent l'élargissement du caecum et l'accumulation de contenus semiliquides chez des rats axéniques. Les flux transépithéliaux de sodium ont été étudiés, dans les conditions de chambre d'Ussing, à travers des parois épithéliales de caecum et de côlon de rats axéniques (GF) ou sans germes pathogènes (SPF). Le transport net du sodium était le plus élevé dans le côlon proximal et dans le segment proximal du côlon distal ; il était considérablement plus faible dans le caecum et dans le segment distal du côlon distal. L'absorption électroneutre du sodium dans le caecum et le côlon proximal était augmentée chez les rats GF par rapport aux rats SFP. Aucune différence n'a été observée dans les segments proximaux du côlon distal. Dans le segment distal du côlon distal, le transport du sodium, surtout électroneutre chez les rats SFP, devenait électrogénique chez les rats GF. Ces différences pourraient être dues aux niveaux accrus d'aldostérone chez les rats GF.

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Section: Electrical Measurementsmentioning

confidence: 99%

Sodium transport across the caecal and colonic epithelium of germfree and specific-pathogen free rats

Rösel¹,

Engelhardt²

1996

Reprod. Nutr. Dev.

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“…However, a number of experiments in the germ-free animal have shown that it cannot be considered simply as a conventional animal, deprived of gastrointestinal microflora, since certain characteristics of its digestive physiology distinguish it from the conventional animal (see reviews by Gordon et al,1966 ;Combe et al, 1976). A knowledge of these characteristics is essential when determining the part due to bacteria in the digestion of an ingested diet.…”

Section: Discussionmentioning

confidence: 99%

“…The large intestine contains the largest bacterial population (1 to 3.10 10 bacteria/g fresh contents) and the greatest number of microbial species in the gut (Ducluzeau and Raibaud, 1975 ;Schaedler, 1973). In some cases, bacteria may efficiently intervene in the digestive utilization of the diet ingested by the animal (R6rat, 1978).However, a number of experiments in the germ-free animal have shown that it cannot be considered simply as a conventional animal, deprived of gastrointestinal microflora, since certain characteristics of its digestive physiology distinguish it from the conventional animal (see reviews by Gordon et al,1966 ;Combe et al, 1976). A knowledge of these characteristics is essential when determining the part due to bacteria in the digestion of an ingested diet.…”

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confidence: 99%

Digestive enzymes in the germ-free animal

Corring¹,

Juste²,

Simoes-Nunes³

1981

Reprod. Nutr. Dévelop.

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Summary.The digestive physiology of the germ-free animal has a number of characteristics (cecal hypertrophy, slower small intestine cell renewal, slower gastric emptying and intestinal transit) which distinguish it from that of the conventional animal. If the germ-free model is to be used to determine the role of gastrointestinal microflora in the nutrition of the conventional animal, it is essential to complete the study of these characteristics by data on digestive enzymes in the germ-free. The present paper analyzes these data.There In general, the germ-free animal has some characteristics which should permit better utilization of the diet ingested. Measurements of apparent digestibility do not confirm this hypothesis since results obtained in germ-free and conventional animals of the same species are contradictory.The germ-free animal is certainly a very useful tool for studying the role of gastrointestinal microflora in the nutrition of its host. The large intestine contains the largest bacterial population (1 to 3.10 10 bacteria/g fresh contents) and the greatest number of microbial species in the gut (Ducluzeau and Raibaud, 1975 ;Schaedler, 1973). In some cases, bacteria may efficiently intervene in the digestive utilization of the diet ingested by the animal (R6rat, 1978).However, a number of experiments in the germ-free animal have shown that it cannot be considered simply as a conventional animal, deprived of gastrointestinal microflora, since certain characteristics of its digestive physiology distinguish it from the conventional animal (see reviews by Gordon et al.,1966 ;Combe et al., 1976). A knowledge of these characteristics is essential when determining the part due to bacteria in the digestion of an ingested diet.The germ-free state in rodents and lagormorphs leads to a substantial increase in cecal sac contents and size (Glimstedt, 1936 ;Wostmann and Bruckner-Kardoss, 1959 ;Wostmann, Bruckner-Kardoss and Knight, 1968 ;Pleasants, 1959 (Guenet et al., 1970). In the chicken, the rate of epithelial cell migration is lower in the germ-free than in the conventional state, but the relative differences are greater in the lower than in the upper intestine (Rolls, Turvey and Coates, 1978).Gastric emptying and small intestinal transit of the ingested food were found to be slower in the germ-free than in the conventional state. Six hours after a labelled test-meal, the cecum of the germ-free mouse retained a greater percentage of radioactivity than the cecum of the conventional animal, and the passage of the marker into the feces was slower (Abrams and Bishop, 1967). Gastrointestinal transit was also slower in the germ-free than in the conventional rat (Sacquet, Garnier and Raibaud, 1970 ;Riottot et al., 1980), and tended to be longer in germ-free rats fed irradiated diets than in those fed autoclaved diets (Riottot et al.,1980). The aim of the present review is to complete our knowledge of the characteristics of germ-free animal digestive physiology by analyzing data on digestive enzymes. These enzymes (p...

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“…It has been demonstrated that the cardiovascular systems of animals reared in the germfree state are altered when compared to conventional animals [15,16,18,19]. The cardiac output of germfree rats is 30% lower than that of conventional controls [19]; total blood volume is re-duced in these animals [19], and there is a reduction in blood flow to certain organ regions [15,18].…”

Section: Introductionmentioning

confidence: 99%

“…The enlarged cecum, characteristically found in rats and three other species reared in gnotobiotic environments, was shown to accumulate a number of substances, which can affect the tone of a variety of smooth muscles [14,16,17], including microvascular smooth muscle [12],The tone of cecal muscle strips is reduced to 67% of control in the presence of these cecal substances, and these strips become less responsive to epi nephrine, acetylcholine and serotonin [25]. One of these active substances, present in larger amounts in the germfree cecum, was identified as epi nephrine inhibitory [12].…”

Section: Introductionmentioning

confidence: 99%

Reactivity of Aorta and Portal Vein in Germfree Rats

Altura¹,

Altura²,

Baez³

1975

J Vasc Res

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The responsiveness of conventional and germfree rat aortas and portal veins to vasoactive agents were compared in vitro. The results indicate: (1) aortas and portal veins from germfree rats exhibit an attenuated reactivity to angiotensin, vasopressin and epinephrine but not to KC1; (2) the dose-response curves for epi-nephrine and the peptides were shifted to the right concomitant with a decrease in maximum contractile tension, and (3) CaCl₂ dose-response curves obtained on potassium-depolarized aorta were not different from one another, whereas those obtained on portal veins from germfree animals were shifted to the right with a concomitant decrease in maximum response. In addition, aortas and portal veins from germfree rats were found to exhibit a higher total Ca content (but not Mg or water) when compared to conventional animals.

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Characteristics of the Germfree Rat

Cited by 63 publications

References 2 publications

Sodium transport across the caecal and colonic epithelium of germfree and specific-pathogen free rats

Sodium transport across the caecal and colonic epithelium of germfree and specific-pathogen free rats

Digestive enzymes in the germ-free animal

Reactivity of Aorta and Portal Vein in Germfree Rats

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