[Islet of Langerhans transplantation. A comparative study of two different methods for isolating islet cells from rat pancreas]. / Transplante de ilhotas de Langerhans. Estudo comparativo entre dois métodos diferentes de isolamento de ilhotas do pâncreas do rato.

Two different methods for isolation of islet of Langerhans on control of metabolic abnormalities of alloxan-induced diabetic rat were tested. Sixty rats were randomly assigned to four experimental groups: GI included 10 non-diabetic control rats, GII included 10 diabetic control rats, without treatment, GIII included 20 diabetic rats (10 inbred and 10 outbred rats) that received islet of Langerhans transplantation (ILT) using islet cells prepared by collagenase, and GIV included 20 diabetic rats (10 inbred and 10 outbred rats) submitted to ILT using islet cells prepared by nonenzymatic method. Clinical and laboratory parameters at beginning and 4, 7, 14, 21 and 30 days of follow-up were recorded. Outbred rats were immunosuppressed with cyclosporin A, diabetes was induced by e.v. alloxan administration, and islet cells were isolated from normal donor Lewis rats and injected into the portal vein. ILT corrected the body weight gain, polyuria, polydipsia, polyphagia, and the high levels of blood and urine glucose in 73.7% of rats treated by enzymatic method and in 64.7% of those ones treated by nonenzymatic method. However, there was no significantly difference between the two methods (P > 0.50). We did not also observe significantly difference between the two methods when ILT was performed either in inbred or outbred rats. We concluded that ILT performed by nonenzymatic method may be an alternative treatment for diabetes due to be less expensive and to have possible advantages in the isolation process.

Effect of long-term treatment with insulin and/or acarbose on glomerular basement membrane thickening in alloxan-diabetic rats.

Acarbose is a competitive inhibitor of the intestinal alpha-glycosidases, that can delay absorption of intestinal carbohydrates causing their malabsorption. In the present paper we studied the effects of insulin, acarbose and their association on glomerular basement membrane thickening in alloxan-diabetic rats. Twenty-five male and female Wistar rats, approximately 3 months old at the beginning of the experiment, were assigned randomly to each of five experimental groups: normal control rats, alloxan-diabetic control rats, alloxan-diabetic rats treated with acarbose, alloxan-diabetic rats treated with insulin, and alloxan-diabetic rats treated with insulin plus acarbose. Alloxan was administered in a single i.v. dose of 442 mg/kg body weight. Insulin was given subcutaneously at doses of 18 to 30 IU/kg corrected daily on the basis of glycosuria and ketonuria. Acarbose was given mixed with rat chow in a dose of 50 mg/100 g chow. Body weight, water and food intake and diuresis, as well as blood and urine glucose were determined after 1, 3, 6, 9, and 12 months of treatment. Glomerular basement membrane (GBM) thickening was determined by electron microscopy at the same times. Clear clinical and laboratory signs of severe diabetes, with blood glucose levels above 200 mg/dl and urine glucose above 3000 mg/dl, were observed in all alloxan-diabetic control rats, in all periods of follow-up, whereas administration of insulin or acarbose reduced the blood glucose levels of treated groups. The most satisfactory control of blood and urine glucose was observed in animals treated with both insulin and acarbose. However, diarrhea was observed in diabetic rats treated with acarbose associated or not with insulin. GBM thickening was correlated with age in all groups. Beginning at six months after diabetes induction, the GBM of untreated diabetic rats was significantly thicker (mean +/- SEM, 4.446 +/- 0.45 mm) than that of normal rats (2.977 +/- 0.63mm). Both insulin and acarbose prevented GBM thickening and their combination induced thickening similar to the age dependent thickening observed for normal rats of the same age. We conclude that acarbose when combined with insulin may be a good option in the control of diabetes and its renal complications.

Effect of long-term treatment with insulin and/or acarbose on glomerular basement membrane thickening in alloxan-diabetic rats

Acarbose is a competitive inhibitor of the intestinal alpha-glycosidases, that can delay absorption of intestinal carbohydrates causing their malabsorption. In the present paper we studied the effects of insulin, acarbose and their association on glomerular basement membrane thickening in alloxan-diabetic rats. Twenty-five male and female Wistar rats, approximately 3 months old at the beginning of the experiment, were assigned randomly to each of five experimental groups: normal control rats, alloxan-diabetic control rats, alloxan-diabetic rats treated with acarbose, alloxan-diabetic rats treated with insulin, and aloxan-diabetic rats treated with insulin plus acarbose. Alloxan was administered in a single iv dose of 42 mg/kg body weight. Insulin was given subcutaneously at doses of 18 to 30 IU/kg corrected daily on the basis of glycosuria and ketonuria. Acarbose was given mixed with rat chow in a dose of 50 mg/100 g chow. Body weight, water and food intake and diuresis, as well as blood and urine glucose were determined after 1, 3, 6, 9, and 12 months of treatment. Glomerular basement membrane (GBM) thickening was determined by electron microscopy at the same times. Clear clinical and laboratory signs of severe diabetes, with blood glucose levels above 200 mg/dl and urine glucose above 3000 mg/dl, were observed in all alloxan-diabetic control rats, in all periods of follow-up, whereas administration of insulin or acarbose reduced the blood glucose levels of treated groups. The most satisfactory control of blood and urine glucose was observed in animals treated with both insulin and acarbose. However, diarrhea was observed in diabetic rats treated with acarbose associated or not with insulin, GBM thickening was correlated with age in all groups. Beginning at six months after diabetes induction, the GBM of untreated diabetic rats was significantly thicker (mean + 4.446 + 0.45 mm) than that of normal rats (2.977 + 0.63 mm). Both insulin and acarbose prevented GBM thickening and their combination induced thickening similar to the age-dependent thickening observed for normal rats of the same age. We conclude that acarbose when combined with insulin may be a good option in the control of diabetes and its renal complications.

[A comparative study of pancreatic-duodenal transplantation, islets of Langerhans transplantation, and insulin treatment, in the control of experimental diabetes in the rat]. / Estudo comparativo entre o transplante pancreato-duodenal, transplante de ilhotas de Langerhans e o tratamento com insulina, no controle do diabetes experimental no rato.

Sixty outbred Wistar rats were randomly assigned to five experimental groups: GI-10 non-diabetic control rats; GII-10 untreated diabetic control rats; GIII-10 diabetic rats treated with retard porcine insulin; GIV-20 diabetic rats that received pancreaticoduodenal transplantation (PDT) from normal donor rats; GV-10 diabetic rats submitted to islet of Langerhans transplantation (ILT) into the portal vein. The animals were housed in metabolic cages for six periods of 24 hours during 30 days and body weight, water and food intake, urine output, blood and urinary glucose were recorded. Diabetes was induced by I.V. administration of Alloxan (42 mg/kg of body weight); PDT was performed by microsurgical techniques and islets were prepared without enzymes. To prevent rejection. Cyclosporin A (10 mg/kg of body weight) was utilized in transplanted rats. PDT consistently and significantly (p < 0.05) improved the metabolic abnormalities of the diabetic rats, by restoring the body weight gain, and immediate relief of polydipsia, polyphagia, polyuria, hyperglycemia and glucosuria observed in pre-treatment period. PDT was more effective than ILT and this over insulin therapy on control of the diabetic state. However, the observed complications in GIV and GV, due to surgery and immunosuppression, should be analysed for the real benefits of the alternative therapy can be superior to eventual fails to the conventional therapy with insulin.

Effects of cyclosporin A immunosuppression on pancreaticoduodenal transplantation in alloxan-diabetic rats.

1. Forty-five outbred Wistar rats were randomly assigned to three experimental groups: GI, 10 non-diabetic control rats; GII, 10 alloxan-diabetic control rats; GIII, 25 alloxan-diabetic rats which received pancreaticoduodenal transplantation (PDT) from normal Wistar donor rats and were immunosuppressed with cyclosporin A (Cy-A), 10 mg kg body weight-1 day-1, administered intraperitoneally for 30 days. 2. In parallel, 15 alloxan-diabetic inbred Wistar rats received isogeneic PDT from normal Wistar donor rats. 3. Cy-A prevented graft rejection in the 15 surviving animals in group III. These observations were confirmed by clinical and biochemical parameters (body weight, urine output, water and food intake, blood and urinary glucose and plasma insulin) and by histology and immunohistochemistry of the pancreas. 4. However, Cy-A was associated with 60% of the infectious complications in transplanted rats leading to 40% mortality. Pulmonary infections were the main cause of death. There were no side effects of immunosuppression on the pancreas. Infections were not significant in inbred rats submitted to PDT.

Metabolic effect of pancreaticoduodenal transplantation in diabetic rats.

Outbred Wistar rats were randomly assigned to three experimental groups: GI, 10 nondiabetic control rats; GII, 10 alloxan-diabetic control rats; GIII, 25 alloxan-diabetic rats that received pancreaticoduodenal transplantation (PDT) from normal donor Wistar rats and were immunosuppressed with cyclosporin A. For 7 prior and 4, 7, 14, 21, and 30 days posttransplantation (during which the animals were housed in metabolic cages for periods of 24 hours) body weight, water and food intake, urine output, blood and urinary glucose, plasma insulin, and glucagon were recorded. These parameters were also concurrently recorded for diabetic and nondiabetic control rats. Animals were sacrificed after 30 days and histological and immunohistochemical studies of the pancreas were performed. Pancreatic transplants consistently and significantly improved the metabolic abnormalities of the diabetic rat (P less than 0.01) by restoring body weight gain, and by immediate relief of hyperglycemia, glucosuria, polyuria, polydipsia, and also the low levels of plasma insulin. The plasma glucagon, elevated in diabetic control rats, did not change after transplant.

Effects of cyclosporin A immunosuppression on pancreaticoduodenal transplantation in alloxan-diabetic rats

1. Forty-five outbred Wistar rats were randomly assigned to three experimental groups: GI, 10 non-diabetic control rats; GII, 10 alloxan-diabetic control rats; GIII, 25 alloxan-diabetic rats which received pancreaticoduodenal transplantation (PDT) from normal Wistar donor rats and were immunosuppressed with cyclosporin A (Cy-A), 10 mg kg body weight-1 day-1, administered intraperitoneally for 30 days. 2. In parallel, 15 alloxan-diabetic inbred Wistar rats received isogeneic PDT from normal Wistar donor rats. 3. Cy-A prevented graft rejection in the 15 surviving animals in group III. These observations were confirmed by clinical and biochemical parameters (body weight, urine output, water and food intake, blood and urinary glucose and plasma insulin) and by histology and immunohistochemistry of the pancreas. 4. However, Cy-A was associated with 60% of the infectious complications in transplanted rats leading to 40% mortality. Pulmonary infections were the main cause of death. There were no side effects of immunosuppression on the pancreas. Infections were not significant in inbred rats submitted to PDT