Marina Rachel Araújo

Rat's age versus human's age: what is the relationship?

BACKGROUND Millions of mice are used annually in research and teaching. The exact relationship between age of the animals compared with the age of humans is still subject to discussion and controversy. OBJECTIVE Literature review analyzing the age of rats in comparison with men age. METHODS Were reviewed the existing publications on the subject contained in Medline / PUBMED, SciELO, The Cochrane Database of Systematic Reviews and Lilacs crossing the headings rats, experimental surgery and physiology. RESULTS Rats rapidly develop during childhood and become sexually mature at about six weeks old, but reach social maturity five to six months later. In adulthood, every month of the animal is approximately equivalent to 2.5 human years. Several authors performed experimental studies in rats and estimated 30 days of human life for every day life of the animal. CONCLUSION The differences in anatomy, physiology, development and biological phenomena must be taken into consideration when analyzing the results of any research in rats when age is a crucial factor. Special care is necessary to be taken when the intention is to produce correlation with human life. For this, special attention is needed to verify the phase in days of the animal and its correlation with age in years of humans.BACKGROUND: Millions of mice are used annually in research and teaching. The exact relationship between age of the animals compared with the age of humans is still subject to discussion and controversy. OBJECTIVE: Literature review analyzing the age of rats in comparison with men age. METHODS: Were reviewed the existing publications on the subject contained in Medline / Pubmed, Scielo, The Cochrane Database of Systematic Reviews and Lilacs crossing the headings rats, experimental surgery and physiology. RESULTS: Rats rapidly develop during childhood and become sexually mature at about six weeks old, but reach social maturity five to six months later. In adulthood, every month of the animal is approximately equivalent to 2.5 human years. Several authors performed experimental studies in rats and estimated 30 days of human life for every day life of the animal. CONCLUSION: The differences in anatomy, physiology, development and biological phenomena must be taken into consideration when analyzing the results of any research in rats when age is a crucial factor. Special care is necessary to be taken when the intention is to produce correlation with human life. For this, special attention is needed to verify the phase in days of the animal and its correlation with age in years of humans

Dietary polydextrose increases calcium absorption in normal rats

BACKGROUND: Gastric surgery is known to cause bone disorders, possibly related to an impaired capacity for the absorption of dietary calcium. AIM: To verify if polydextrose (PDX) could stimulate calcium absorption in partially gastrectomized and sham operated rats. METHODS: The rats were laparotomized (sham-operated control) or partially gastrectomized (Billroth II), in groups of 20 each. Half in each operated group were fed a control diet (AIN-93M) without PDX or the same diet containing (PDX 50g/Kg of diet) for eight weeks. The rats were divided into four subgroups: sham-operated and gastrectomized without PDX; sham-operated and gastrectomized with PDX. On the final day of the study, total blood was collected for determination of serum calcium concentration. RESULTS: In the diet with PDX, excretion of calcium in the feces was significantly lower than in the groups not receiving PDX, irrespective of the operation. Apparent calcium absorption and serum calcium was higher in the sham operated PDX fed group than in the control group. In sham operated rats, the calcium concentration in bone was higher in the PDX fed group. CONCLUSION: The polydextrose feeding increased calcium absorption and bone calcium concentration in normal rats, which may be relevant for decreasing the risk of osteoporosis. Partially gastrectomy did not affect the bone calcium concentration in 56 days of experimental period.

Ingestion of polydextrose increase the iron absorption in rats submitted to partial gastrectomy

PURPOSE To investigate whether polydextrose stimulates iron absorption in rats submitted to partial gastrectomy and sham operated. METHODS The rats were submitted to partial gastrectomy (Billroth II) or laparotomy (sham-operated control), in groups of 20 and 20 each respectively. The animals were fed with a control diet (AIN-93M) without polydextrose or a diet containing polydextrose (50g/Kg of diet) for eight weeks. They were divided into four subgroups: sham-operated and Billroth II gastrectomy and with or without polydextrose. Two animals died during the experiment. All rats submitted to gastrectomy received B-12 vitamin (intramuscular) each two weeks. The hematocrit and hemoglobin concentration were measured at the start and on day 30 and 56 after the beginning of the experimental period. At the end of the study, the blood was collected for determination of serum iron concentration. RESULTS The diet with polydextrose reduced the excretion of iron. Apparent iron absorption was higher in the polydextrose fed groups than in the control group. The haematocrit and haemoglobin concentration were lower after Billroth II gastrectomy rats fed the control diet as compared to the polydextrose diet groups. CONCLUSION Polydextrose increase iron absorption and prevents postgastrectomy anemia.

Late histological aspects of spleen autologous transplantation in rats

PURPOSE To evaluate macro and microscopically the late evolution of autotransplants of fragments of spleen in the greater omentum, mesenterium and peritoneal cavity, after 24 weeks of observation. METHODS Fifty two Wistar rats were used, males and adults, submitted to total splenectomy and divided in four groups. The group I--seventeen animals with implant of spleen fragment in the peritoneal cavity; group II--eighteen animals with implant in the omentum and group III--seventeen animals with implant fixed in mesenterium root. The group control (group IV) was formed by eight animals chosen aleatorily among the three groups. It was analyzed macro and microscopically the evolution of the implant, and in the histological study qualitative and quantitative criteria were adopted, with the counting of no cellular e cellular elements. RESULTS It was observed adherences to the adjacent tissues and vascularization in all of the fragments transplanted. The group I presented white pulp and preserved vascularization. In the group II were observed white pulp with follicular formations and lymphoid tissue preserved, and the red pulp in cordon aspect and hemorrhagic. In the group III were observed with depletion of white and red pulp, while others evidenced better preservation of the pulps. The counting of lymphocytes revealed significant difference between the groups I and IV and the group III and IV (p < 0.05). The counting of active macrophages revealed significant difference between the groups II and III (p < 0.05) and similarity between II and IV (p > 0.05). The other elements: active macrophages phagocyting hemosiderine, plasmocytes, fibroblasts, fibrocytes, giant cells, monocytes, interstitial spaces and fibers of collagen, did not show significant difference among the groups. CONCLUSIONS The splenic autotransplantation is feasible, being the better place the greater omentum. This research demonstrated through qualitative and quantitative histological analysis that the splenic tissue autotransplanted in the omentum of Wistar rats preserves its function of defense of the organisms.

Role of the vitamin C in diethylnitrosamine-induced esophageal cancer in Wistar rats.

PURPOSE To evaluate the inhibitory effect of vitamin C on the experimental esophageal carcinogenesis induced by diethylnitrosamine (NDEA). METHODS Sixty Wistar male rats aged three months, with mean weight of 210 g were employed in the study and were divided into four different groups according to the drinking drugs: group I--controls: only water, seven days a week; group II--only vitamin C, seven days a week; group III--NDEA, three days a week and water during the other four days; group IV--NDEA, three days a week and vitamin C during the other four days; group V--NDEA together with vitamin C three days a week, and only water during the other four days and group VI--NDEA together with vitamin C three days a week and vitamin C during the other four days. The dosages of NDEA were: --10 mg./Kg/day and vitamin C--200 mg/animal/day, dissolved in drinking water. The animals were observed during 180 days and after that each one was sacrificed and its esophagus and the stomach were removed together and macro and microscopically analyzed to identify any tumors. RESULTS The largest number of tumors was observed in the group III: 48 macroscopic lesions (4.8 lesions per animal) and 23 microscopic lesions (2.3 lesions per animal). The groups that received vitamin C (groups IV, V and VI) showed smaller number of tumors: group V--0.5 macroscopic lesions and 0.3 microscopic lesions per animal and group VI--0.1 macroscopic lesions and 0.1 microscopic lesions per animal. The incidence of tumors in the groups V and VI showed statistical significance (p<0.05), when compared to the other groups. CONCLUSION The vitamin C administered together with diethylnitrosamine showed an inhibitory effect on the experimental esophageal carcinogenesis in Wistar rats.

Partial gastrectomy associated to anterior truncal vagotomy: alterations in metabolism of the calcium. Experimental study in rats

RACIONAL: O calcio nao e absorvido na ausencia de acido cloridrico e a osteomalacia e osteoporose podem ocorrer; este fato e bem reconhecido em pacientes que se submeteram a gastrectomias. OBJETIVO: Avaliar os efeitos da gastrectomia parcial associada a vagotomia troncular anterior na absorcao e metabolismo de calcio. METODOS: Dezoito ratos Wistar machos e adultos foram submetidos a gastrectomia parcial e vagotomia troncular anterior (oito animais) e a laparotomia simples como grupo controle (10 animais). O consumo de dieta e o peso dos animais foram monitorados tres vezes por semana. Os animais receberam dieta oral formulada experimentalmente (AIN-93M), durante 8 semanas. O calcio serico, calcio urinario e fecal, absorcao aparente de calcio, atividade da enzima fosfatase alcalina e calcio osseo foram mensurados apos 60 dias de observacao. RESULTADOS: Os animais controle apresentaram medias estatisticas maiores (P<0.05) para o consumo de dieta, ganho de peso, calcio serico, calcio urinario, excrecao de calcio nas fezes, absorcao aparente de calcio e atividade da enzima fosfatase alcalina comparados aos animais do grupo gastrectomizado. Entretanto, a concentracao de calcio osseo foi superior no grupo de animais gastrectomizados (P<0,05) quando comparado com o grupo controle. CONCLUSAO: A gastrectomia parcial associada a vagotomia troncular anterior mostrou ser um bom modelo experimental para estudo com o metabolismo de calcio, ocasionando diminuicao da absorcao de calcio, calcio serico, calcio urinario e fosfatase alcalina. No entanto, para alteracoes a nivel osseo em ratos, sugere-se um estudo experimental em periodo maior.

Influência da dieta com galactooligossacarídeos sobre a absorção de cálcio em ratos normais e gastrectomizados

OBJECTIVE To determine whether the galactooligosaccharide stimulates calcium absorption in partially gastrectomized rats. METHODS Animals were submitted to laparotomy (sham-operated control) and partial gastrectomy (Billroth II) in groups of 20. They were fed a control diet (AIN-93M) without galacto-oligosaccharide or a diet containing (galacto-oligosaccharide - 50 g/kg diet) for eight weeks. The animals were divided into four groups: sham-operated and non-gastrectomized with galactooligosaccharide, sham-operated and gastrectomized without galactooligosaccharide. On the final day of the study, whole blood was collected for determination of serum calcium concentration. RESULTS In the group with galactooligosaccharides calcium excretion in feces was significantly lower than the group without prebiotics. The apparent absorption of calcium in gastrectomized and normal rats was higher in groups fed with galactooligosaccharide than in the control diet group. CONCLUSION The ingestion of galactooligosaccharides prevents osteopenia in partially gastrectomized rats.

Idade dos ratos versus idade humana: qual é a relação?

BACKGROUND Millions of mice are used annually in research and teaching. The exact relationship between age of the animals compared with the age of humans is still subject to discussion and controversy. OBJECTIVE Literature review analyzing the age of rats in comparison with men age. METHODS Were reviewed the existing publications on the subject contained in Medline / PUBMED, SciELO, The Cochrane Database of Systematic Reviews and Lilacs crossing the headings rats, experimental surgery and physiology. RESULTS Rats rapidly develop during childhood and become sexually mature at about six weeks old, but reach social maturity five to six months later. In adulthood, every month of the animal is approximately equivalent to 2.5 human years. Several authors performed experimental studies in rats and estimated 30 days of human life for every day life of the animal. CONCLUSION The differences in anatomy, physiology, development and biological phenomena must be taken into consideration when analyzing the results of any research in rats when age is a crucial factor. Special care is necessary to be taken when the intention is to produce correlation with human life. For this, special attention is needed to verify the phase in days of the animal and its correlation with age in years of humans.BACKGROUND: Millions of mice are used annually in research and teaching. The exact relationship between age of the animals compared with the age of humans is still subject to discussion and controversy. OBJECTIVE: Literature review analyzing the age of rats in comparison with men age. METHODS: Were reviewed the existing publications on the subject contained in Medline / Pubmed, Scielo, The Cochrane Database of Systematic Reviews and Lilacs crossing the headings rats, experimental surgery and physiology. RESULTS: Rats rapidly develop during childhood and become sexually mature at about six weeks old, but reach social maturity five to six months later. In adulthood, every month of the animal is approximately equivalent to 2.5 human years. Several authors performed experimental studies in rats and estimated 30 days of human life for every day life of the animal. CONCLUSION: The differences in anatomy, physiology, development and biological phenomena must be taken into consideration when analyzing the results of any research in rats when age is a crucial factor. Special care is necessary to be taken when the intention is to produce correlation with human life. For this, special attention is needed to verify the phase in days of the animal and its correlation with age in years of humans

A ingestão de prébioticos previne a malabsorção de ferro e anemia induzidas pela gastrectomia?: Estudo experimental em ratos

BACKGROUND: The ingestion of two prebiotics, galactooligosaccharide (GOS) and polydextrose (PDX), leads to an increase in iron absorption and promotes recovery from anemia in gastrectomized rats. AIM: To study whether GOS + PDX stimulate iron absorption in gastrectomized and normals rats. METHODS: Rats were laparotomized (sham-operated control) and partially gastrectomized (Billroth II) in groups of 20 each. Animals from both treatments were subsequently fed a control diet (AIN-93M) or the same diet supplemented with GOS and PDX (25 g/Kg of diet each) for eight weeks. They were divided into four subgroups, i.e., sham-operated and gastrectomized without GOS + PDX, sham-operated and gastrectomized with GOS + PDX. Two rats died during the experiment. All gastrectomized rats received an intramuscular injection of vitamin B-12 every two weeks. Hematocrit (HCT) and hemoglobin concentration (HGB) were measured at the start and on day 30 and 56 days after the start of feeding. On the final day of the study, total blood was collected for determination of serum iron concentration. RESULTS: In the diet with GOS + PDX, iron excretion in feces was significantly lower than without the prebiotics. Apparent iron absorption and serum iron was higher in the GOS + PDX fed groups (both sham operated and gastrectomized) than in the non-GOS + PDX fed groups. The HCT and HGB concentrations were significantly lower in gastrectomized rats than in the control group, however, GOS + PDX feeding improved HGB levels in this group. CONCLUSION: The association of the GOS + PDX increase absorption of iron in sham-operated and gastrectomized rats and still prevent postgastrectomy anemia.

Effects of the partial gastrectomy associated to anterior truncal vagotomy in the metabolism of the iron in rats

PURPOSE To evaluate the effects of the partial gastrectomy associated to anterior truncal vagotomy in the absorption and metabolism of iron. METHODS Eighteen adults male Wistar rats were submitted to the partial gastrectomy associated to anterior truncal vagotomy (eight animals) and the sham operation (10 animals, control group). The diet consumption and the weight gains of the animals were monitored three times during the week. The animals received supplements of vitamin B12, for the prevention of the megaloblastic anemia, and a formulated experimental diet orally and denominated AIN-93M by 8 weeks. The fecal iron, apparent absorption of the iron, haematocrit, haemoglobin and serum iron were measured after 60 days. RESULTS The animals undergoing sham operation presented larger statistical averages (p<0.05) for the diet consumption, weight gains, apparent absorption of iron, haematocrit, haemoglobin and serum iron compared to the gastrectomized group. However, the excretion of iron in feces was larger in the gastrectomized group (+14.3%) (p<0.05) when compared to the control group. CONCLUSION Partial gastrectomy associated to anterior truncal vagotomy showed to be a good experimental model the study of iron metabolism, decreasing the haematocrit, the haemoglobin and the iron absorption, consequently causing anemia.