Alcino Lázaro da Silva

Subtotal splenectomy preserving the lower pole in rats: technical, morphological and functional aspects

PURPOSE To assess the possibility of preserving the lower pole of the spleen, supplied by the inferior lobar vessels and segmental vessels, or by vessels of the gastrosplenic ligament, in subtotal splenectomy; to study the viability and function of the lower pole of the spleen. METHODS Thirty-six male Wistar rats were used in this study. Said animals weighed 273-390 g ( 355.2 +/- 30.5 g ), and were randomly distributed into three groups. Group 1 comprised ten animals which were submitted to exploratory laparotomy with spleen manipulation (sham operation). Group 2 comprised 16 animals which were submitted to total splenectomy. Group 3 comprised ten animals which were submitted to subtotal splenectomy, preserving the lower pole of the spleen. Blood was collected from all animals before and 90 days after surgery to measure the levels of cholesterol and triglycerides. The animals were sacrificed 90 days after surgery. Spleens and remaining spleens were removed for macroscopic and microscopic examination. RESULTS Surgery was performed with no complications in all groups. Six animals died in group 2. Spleens of groups 1 and 2, and lower poles of group 3 were macroscopically viable. Apparent white pulp hyperplasia was observed in group 1. In group 3, slight inflammation and capsular fibrosis were observed at the incision site, as well as diffuse hemosiderosis in the red pulp. Average mass of remaining spleen was 35.84% +/- 4.31%. No significant difference was observed between preoperative and late postoperative lipid levels in groups 1 and 3 (p > 0.05). Late postoperative lipid levels significantly increased in group 2. CONCLUSIONS Preservation of the lower pole of the spleen (supplied by gastrosplenic vessels or inferior lobar vessels and segmental vessels) was possible with subtotal splenectomy. The lower pole was macroscopically and microscopically viable in all cases. Subtotal splenectomy preserving the lower pole prevented changes in lipid levels, which were observed in rats submitted to total splenectomy. Plasma lipid levels in rats submitted to subtotal splenectomy were similar to those observed in sham operated rats.

Lipídios plasmáticos após esplenectomia total e parcial em cães

OBJETIVO: Avaliar o efeito da esplenectomia total e parcial (hemiesplenectomia e esplenectomia subtotal) no lipidograma de caes. METODO: Foram operados 38 animais, adultos, machos, mesticos, com peso entre 13kg e 15kg. No pre-operatorio, depois do exame clinico e jejum de 12 horas de uma dieta-padrao, foram realizados hemograma e lipidograma. Apos anestesia geral com tiopental sodico os caes foram submetidos a laparotomia mediana supra e infra-umbilical. Procedeu-se no grupo 1, de sete caes, apenas a manipulacao do baco (simulado); no grupo 2, de nove caes, a hemiesplenectomia cranial; no grupo 3, de nove caes, a esplenectomia subtotal, com preservacao do polo inferior do baco, apos ligadura e seccao dos troncos principais dos vasos esplenicos proximos ao hilo; e no grupo 4, de 13 caes, a esplenectomia total. RESULTADOS: No grupo 4 (esplenectomia total), quando comparamos os valores do lipidograma dos diferentes periodos pos-operatorios com os do pre-operatorio, os nossos resultados mostraram que houve aumento significante do colesterol total em todos os periodos pos-operatorios (p 0,05) no 56o PO. O LDL aumentou significantemente no 56o PO (p < 0,01) em relacao tambem aos demais periodos do pos-operatorio. Os triglicerideos e VLDL nao apresentaram alteracoes significantes. Nos animais dos grupos 1 e 3 nao houve alteracoes significantes. Nos do grupo 2, houve aumento significante do colesterol no 7o PO. Nao houve diferenca estatisticamente significante de peso entre os remanescentes das esplenectomias parciais. CONCLUSOES: A analise dos resultados nos permitiu concluir que a esplenectomia total induz aumento significante do colesterol total, das fracoes HDL e LDL, enquanto os niveis de trigliceridios e a fracao VLDL nao sofrem alteracoes; a conservacao da metade inferior do baco ou a esplenectomia subtotal, com preservacao do polo inferior, protege o animal de alteracoes lipidicas significantes.

Ética e experimentação animal

Medical ethics that becomes more and more consolidated and important underwent modifications because of experiences with animals. This humanitarian movement initiated some time ago is now picking the best results, with permanent attention an care regarding this aspect at the Brazilian Medical Universities. The animal involuntarily involved, contribute with medical and surgical research and should be respected. The results should benefit both

Heat shock response reduces mortality after severe experimental burns.

The heat shock response has imparted protective effects in animal models of septic shock and endotoxemia. This study has tested the hypothesis that it could be protective in experimental burns. One hundred and fifteen adult male Fischer rats were randomly divided into four groups. Rats in the first group (n = 12) were anesthetized and shaved. In the second group (n = 15) rats were anesthetized and heated in a 45 degrees C water bath. In the third group (n = 44), rats were anesthetized, shaved and submitted to 26-30% body surface third-degree burns using a brass bar. In the fourth group (n = 44), rats were anesthetized, heated and, 1 day after, they were burnt. Mortality rates were measured at 3, 7, 15 and 25 days. Liver and lung samples were collected from all groups for heat-shock protein 70 detection. Heat-shock protein 70 was positive in heated animals. No animals died in the first or second group. Heated and burnt animals showed significantly decreased mortality at days 3 (p < 0.05, Fischers exact test) and at days 7, 15 and 25 (p < 0.01) after burns, when compared to unheated burnt animals. In conclusion, eliciting the heat-shock response significantly reduced mortality rates in this model of experimental burns.

A standard burn model using rats

Experimental burn models are always needed, being essential for burn research. In the present study, we describe a standard Fischer F-344 rat burn model, in which burns are produced with a heated brass bar. The animals were anesthetized with ketamine (90 mg/kg). After the burns, they were resuscitated with saline. Burns ranging from 26% to 30% of total body surface area resulted in a 62.5 % mortality rate after 25 days. This model is an additional option for those interested in burn research.

Esplenectomia subtotal, em cães, com preservação do pólo inferior(PI) suprido por vasos do ligamento gastroesplênico

O objetivo desse trabalho foi estudar a viabilidade do polo inferior (PI) do baco de caes, apos a ligadura e seccao da arteria e veia esplenicas. Foram operados 24 caes, mesticos, machos, com peso variando entre 12kg e 14kg. Os animais anestesiados foram submetidos a laparotomia mediana supra e infra-umbilical, com 12cm de comprimento. Nos do grupo 1 fez-se a ligadura e seccao da porcao superior do ligamento gastroesplenico, ligadura e seccao da arteria e veia esplenicas. Apos a ligadura do ramo descendente dos vasos esplenicos, o baco foi seccionado transversalmente, a superficie de corte do PI foi suturada e a peca enviada para estudo microscopico. A parede abdominal foi suturada por planos. Os caes foram mantidos vivos e sacrificados no setimo (subgrupo I A - quatro caes), 15° (subgrupo 18 - cinco caes), trigesimo (subgrupo I C - quatro caes) e septuagesimo dia (subgrupo I D - tres caes). Nessa ocasiao, o Pl foi retirado para estudo. No grupo 2, tres caes foram submetidos a laparotomia e manipulacao do baco (controle 2 - simulacao), para controle morfologico. Esse procedimento foi feito no 15° dia (subgrupo 2A - dois caes) e no sexagesimo dia (subgrupo 28 - um cao). Dos 24 caes operados, cinco foram a obito. A causa foi evisceracao (dois caes), hemorragia intraperitoneal (um cao), hemorragia digestiva baixa de causa nao esclarecida (um cao) e indeterminada (um caso). O exame macroscopico do PI comparado aquele dos controles I e 2 mostrou aspecto duvidoso em apenas dois casos, onde o PI apresentava-se aderido firmemente a parede abdominal e alcas intestinais. Nao houve, no entanto, diferenca estatisticamente significante (p>O.O5 - teste exato de Fisher) no numero de casos viaveis entre os grupos controles e grupo I. O exame microscopico do PI, comparado aqueles do restante do baco (controle I) e ao controle 2 (simulacao), mostrou que a referida porcao apresentou alteracoes morfologicas discretas, na maioria dos casos, e sinais de regressao em dois casos. Esse numero nao induziu, tambem, resultados estatisticamente significante (p>O.O5). A analise dos nossos resultados nos permitiu concluir que o PI do baco de caes manteve-se viavel em 86,6% dos casos, mesmo com a ligadura da arteria e veia esplenicas.

Effects of peritoneal lavage with lidocaine on survival of rats with fecal peritonitis.

PURPOSE To study the effects of peritoneal lavage with a 2% lidocaine solution, on the survival of the rats submitted to peritonitis caused by their own feces. METHODS Forty-eight Wistar rats, weighting between 300 g and 330 g (mean, 311,45 +/-9,67 g), were submitted to laparotomy 6 hours following induction of fecal peritonitis. Animals were randomly divided into four groups of 12 each as follows: 1- Control, no therapy; 2- Drying of the abdominal cavity; 3- Peritoneal lavage with saline and drying; 4- Peritoneal lavage with a 2% lidocaine solution and drying. Animals that died were submitted to necropsy and the time of their death recorded; survivors were killed on the post-operation 11th day and necropsied. RESULTS Death occurred within 52 h in all animals of group 1; within 126 h in 100% of those of group 2; within 50 h in 50% of those of group 3. All animals of group 4 survived. Survival on the 11 th day was higher in groups 3 and 4 than in groups 1 and 2 (p<0.001), and higher in group 4 than in group 3 (p<0.01). CONCLUSION Peritoneal lavage with a 2% lidocaine saline solution without adrenaline, prevented the mortality of all animals with fecal peritonitis.

Effect of hyperbaric oxygen therapy in rats with subtotal splenectomy preserving the inferior pole

PURPOSE To evaluate the effect of hyperbaric oxygen therapy on the survival and weight of rats submitted to subtotal splenectomy and on the viability and growth of the inferior pole. METHODS Forty Wistar rats underwent subtotal splenectomy with preservation of the inferior pole and distributed into two groups: Group A (n=20) - not treated with hyperbaric oxygen, Group B (n=20) – treated with hyperbaric oxygen. These groups were divided into two subgroups of 10 animals each, according to the time of euthanasia, 15th and 45th days. The survival and weight of the animals were recorded. The inferior pole was measured, weighed and morphologically analyzed. RESULTS All animals survived. The weight of the animals increased in all subgroups, but decreased on the 10th day in the subgroups treated with hyperbaric oxygen (p<0.001). The viability of the inferior pole was more evident in animals treated on the 15th day, but did not differ on the 45th day. The growth of the inferior pole has not occurred on the 15th day but on the 45th day after surgery in untreated animals (p<0.01) and treated animals (p<0.05). Vascular and cellular increase in treated animals was significantly higher than in untreated ones. CONCLUSION Hyperbaric oxygen therapy did not affect the survival of animals but reduced their weight. It improved the viability of the inferior splenic pole, but did not interfere with their growth.

Níveis de lípides plasmáticos em ratos submetidos à esplenectomia total, ligadura simultânea dos vasos esplênicos e à esplenectomia subtotal com preservação do pólo inferior

BACKGROUND: To verify the effect on plasmatic lipid level of rats feed with control diet and diet added with 2.5% pure cholesterol after total splenectomy, ligature of the splenic vessels and partial splenectomy with preservation of the inferior pole. METHODS: One hundred and eleven male Wistar rats weighting between 273 and 427g aged 12 weeks, were randomly divided into 5 groups. Group 1 (N = 20) control group was not submitted to surgery; Group 2 (N = 20) submitted to manipulation of the spleen; Group 3 (N = 31) total splenectomy; Group 4 (N = 20) simultaneous ligature of the splenic artery and vein; Group 5 (N = 20) partial splenectomy with preservation of the inferior pole. Plasmatic lipids levels were measured and the animals divided in two subgroups according to the type of diet: subgroup A control diet, subgroup B had a 2.5% pure cholesterol added to the control diet. All animals were killed ninety days after the beginning of the experiment, following a new dosage of plasmatic lipids. RESULTS: Animals submitted to total splenectomy, independently of any diet, showed significant increase (p < 0.05) in total cholesterol, LDL, VLDL and triglycerides. The increase of HDL was significant in the rats fed with control diet (p < 0.05) and non significant in the rats submitted to the diet with pure cholesterol (p = 0.29). The animals submitted to simultaneous ligature of vein and artery and to control diet did not show significant alteration of the plasmatic lipids. In the group submitted to diet added with pure cholesterol, we observed a significant increase (p < 0.05) in total cholesterol, VLDL and triglycerides, although the levels of HDL were the same. Animals submitted to partial splenectomy with preservation of the inferior pole and to control diet, did not show significant alterations (p < 0.05) in total cholesterol, LDL, VLDL and triglycerides, but did in HDL (p < 0.05). In those with diet with cholesterol we observed an increase in total cholesterol, LDL, VLDL and triglycerides but not in HDL. CONCLUSIONS: Total splenectomy leads to a significant increase of total cholesterol, LDL, VLDL and triglycerides, independently of the type of diet. The increase is more significant in the animals that received their diet with a 2.5% pure cholesterol. Simultaneous ligature of splenic artery and vein, partial splenectomy with preservation of the inferior pole protect against the alterations in the levels of plasmatic lipids observed in rats submitted to total splenectomy in both types of diet.

O pólo inferior do baço de ratos e a oxigenoterapia hiperbárica

OBJECTIVE: To study the functional and morphological features of the lower pole of the spleen in rats submitted, or not, to postoperative hyperbaric oxygen therapy. METHODS: Seventy-nine Wistar rats, weighing 248.7 ± 27 g, divided into two groups [group A - simulation (n=40), group B - lower pole (n=39)] underwent surgery and were subdivided into two groups: 11 and 70 postoperative days. Each subgroup was subdivided into animals not treated (nt) (A11nt, n=10; B11nt, n=13; A70nt, n=10; B70nt, n=9) and treated with hyperbaric oxygen (t) (A11t, n=10; B11t, n=9; A70t, n=10; B70t, n=8). Blood was collected for measurement of lipids and immunoglobulins, platelet and Howell-Jolly body count before and after surgery. The spleen and lower pole were removed for histology. RESULTS: There was an increase of total cholesterol (p=0.002), VLDL-cholesterol and triglycerides (p=0.003) and of LDL-cholesterol (p=0.013) in subgroup B11nt, and no alterations were observed in the other subgroups. IgM decreased in subgroups B11t (p=0.007), B11nt (p=0.0000), B70nt (p=0.0005), B70t (p=0.02), and no change was observed in the simulation group. The number of platelets increased in subgroups B11nt (p=0.002) and B11t (p=0.01) and remained unchanged in the other subgroups. Howell-Jolly bodies were less numerous in subgroup B70nt than in subgroup B11nt (p=0.019). Lower pole viability was better in subgroup B11t than in B11nt and in subgroup B70 than in B11, and did not differ between subgroups B70t and B70nt. CONCLUSION: Function and viability of the remaining lower pole improved during the late postoperative period. Viability and function of the lower pole were better during the early but not during the late postoperative period, in animals submitted to hyperbaric oxygen therapy.