Antioxidant, Antidiabetic and Lipid Profiling of Spermadicyton Suaveolens in Streptozotocin (STZ) Induced Diabetic Rats

ABSTRACT Diabetes is a life-threatening disease, and currently available synthetic medicines for treating diabetes are associated with various side effects. Therefore, there is an unmet need to develop herbal remedies against diabetes as an alternative to synthetic medicines. Although local healers use the roots of Spermadicyton suaveolens (SS) to manage diabetes, there is negligible research to validate its antidiabetic properties. The present investigation aims to the assess the antioxidant, antidiabetic, and antihyperlipidemic potential of the ethanolic extract of S. Suaveolen's roots (EESS) on streptozotocin (STZ) induced diabetic rats. The extract was screened for in vitro antioxidant and antidiabetic activity. The in vivo antidiabetic potential of EESS (at 200 and 400 mg/kg) was studied on STZ-induced diabetic rats for 20 days. The EESS displayed significant (p<0.05) antidiabetic and antioxidant properties. The administration of 200 mg/kg and 400 mg/kg EESS in STZ-induced diabetic rats significantly reduced hyperglycemia, and restored antioxidant enzymes and lipid profile-a high density lipoprotein (HDL) increased by the administration of a single dose of streptozotocin. Thus, EESS could be a promising herbal medicine in the treatment of diabetes and hyperlipidemia

Phytochemicals of Periploca aphylla Dcne. ameliorated streptozotocin-induced diabetes in rat

BACKGROUND@#Periploca aphylla is used by local population and indigenous medicine practitioners as stomachic, tonic, antitumor, antiulcer, and for treatment of inflammatory disorders. The aim of this study was to evaluate antidiabetic effect of the extract of P. aphylla and to investigate antioxidant and hypolipidemic activity in streptozotocin (STZ)-induced diabetic rats.@*METHODS@#The present research was conducted to evaluate the antihyperglycemic potential of methanol extract of P. aphylla (PAM) and subfractions n-hexane (PAH), chloroform (PAC), ethyl acetate (PAE), n-butanol (PAB), and aqueous (PAA) in glucose-overloaded hyperglycemic Sprague-Dawley rats. Based on the efficacy, PAB (200 mg/kg and 400 mg/kg) was tested for its antidiabetic activity in STZ-induced diabetic rats. Diabetes was induced via intraperitoneal injection of STZ (55 mg/kg) in rat. Blood glucose values were taken weekly. HPLC-DAD analysis of PAB was carried out for the presence of various polyphenols.@*RESULTS@#HPLC-DAD analysis of PAB recorded the presence of rutin, catechin, caffeic acid, and myricetin. Oral administration of PAB at doses of 200 and 400 mg/kg for 21 days significantly restored (P < 0.01) body weight (%) and relative liver and relative kidney weight of diabetic rats. Diabetic control rats showed significant elevation (P < 0.01) of AST, ALT, ALP, LDH, total cholesterol, triglycerides, LDL, creatinine, total bilirubin, and BUN while reduced (P < 0.01) level of glucose, total protein, albumin, insulin, and HDL in serum. Count of blood cells and hematological parameters were altered in diabetic rats. Further, glutathione peroxidase, catalase, superoxide dismutase, glutathione reductase, and total soluble protein concentration decreased while concentration of thiobarbituric acid reactive substances and percent DNA damages increased (P < 0.01) in liver and renal tissues of diabetic rats. Histopathological damage scores increased in liver and kidney tissues of diabetic rats. Intake of PAB (400 mg/kg) resulted in significant improvement (P < 0.01) of above parameters, and results were comparable to that of standard drug glibenclamide.@*CONCLUSION@#The result suggests the antihyperglycemic, antioxidant, and anti-inflammatory activities of PAB treatment in STZ-compelled diabetic rat. PAB might be used as new therapeutic agent in diabetic patients to manage diabetes and decrease the complications.

Effect of genistein on the pancreas of streptozotocin-induced diabetic male rats: light and electron microscopic study

Diabetes mellitus is a worldwide serious health problem. The critical need for novel therapeutic approaches to treat diabetes mellitus is clear. Genistein, a natural soy isoflavone, have numerous health benefits attributed to multiple biological functions. To investigate the effect of genistein on the structure of pancreatic beta cells and acinar cells in streptozotocin-induced diabetic rats. Thirty adult male albino rats were classified into: group I [control], group II in which diabetes was induced by a single intraperitoneal injection of streptozotocin [STZ] [80 mg/kg] and group 111 in which the diabetic rats were injected subcutaneously with genistein [0.25 mg/kg/day] Alter 3 months, blood glucose concentrations were assessed and pancreas specimens were processed lor light and electron microscopic study. Immunohistochemical insulin reactivity and morphometric analysis of the islet diameter were also studied. STZ, in group II rats, caused shrinkage of the pancreatic islet and induced beta cell damage in addition to weak insulin immunoreactivity and elevated blood glucose level. Many Icinar cells of this group showed accumulated zymogen granules, pleomorphic mitochondria and small lipid droplets. Genistein, in group III rats, preserved beta cell mass as evidenced by the large islets with strong insulin immunoreactivity and the significant reduction in blood glucose level. Ultrastructurally, beta cells of group III rats had numerous secretory granules and well developed Golgi bodies. Iknvever, the acinar cells of genistein treated rats exhibited more structural changes than group II with loss of the normal polarity and marked damage of mitochondria. Zymogen granules exhibited low electron density with frequent docking to the lateral plasma membrane and granule-granule fusion. Genistein protected the beta cells against STZ-induced damage. However its deleterious effect on the pancreatic acinar cells might limit its benefit as a promising therapy for diabetes mellitus

Caracterización de un modelo de diabetes tipo 2 en ratas y evaluación del papel de la angiotensina II y las especies reactivas de oxígeno en la resistencia neuronal a la insulina / Characterization of a type 2 diabetes model in rats and evaluation of the role of angiotensin II and reactive oxygen species in neuronal insulin resistance

La regulación ejercida por la insulina central en individuos diabéticos ha sido muy poco estudiada. La angiotensina II promueve el estrés oxidativo y la resistencia a la insulina. Dada la co-localización del receptor AT1 de la angiotensina II y el RI a nivel hipotalámico, en este trabajo, decidimos evaluar el efecto de la angiotensina II sobre las acciones centrales de la insulina en condiciones diabéticas, a través de un modelo animal de DM2 en ratas Sprague-Dawley, así como el posible efecto protector del tratamiento crónico con Valsartán. El modelo fue caracterizado y validado a través de la medición de diversos parámetros metabólicos, usando técnicas enzimáticas e inmunoenzimáticas. Los efectos de la angiotensina II sobre la señalización y acciones biológicas de la insulina a nivel hipotalámico fueron evaluadas in vivo e in vitro, mediante western blot, así como los cambios en los niveles de glicemia en las ratas tratadas ICV con ANG II y/o insulina. Fue evaluado además, el estado oxidativo a nivel hipotalámico, mediante la determinación de enzimas antioxidantes, así como el estado inflamatorio sistémico, mediante la determinación fluorométrica de citoquinas plasmáticas. El modelo experimental desarrollado mimetizó las características fenotípicas de la DM2. El valsartán previno parcialmente la resistencia a la insulina. En condiciones normales, se demostró que la angiotensina es capaz de inhibir la señalización de la insulina a nivel hipotalámico por un mecanismo dependiente de ERO. En condiciones diabéticas, hay una disminución basal de la activación de las proteínas de señalización de la insulina, la cual fue prevenida por el tratamiento con valsartán. El efecto hipoglicemiante inducido por la insulina central fue significativamente reducido en condiciones diabéticas. El tratamiento ICV con angiotensina II antagonizó los efectos hipoglicemiantes de la insulina central y este efecto fue potenciado en condiciones diabéticas. El valsartán bloquea la acción inducida por la ANG II ICV en todos los grupos. Los resultados demuestran que existe un estado de resistencia a la insulina en nuestro modelo de DM2, evidente tanto a nivel molecular como fisiológico, el cual es potenciado por la angiotensina y prevenido parcialmente por el tratamiento crónico con valsartán.

Diabetes-induced prefrontal nissl substance deficit and the effects of neem-bitter leaf extract treatment / Diabetes inducida por déficit prefrontal de sustancia de nissl y el efecto del tratamiento con extracto de hoja de neem amargo

Cognitive dysfunction is reportedly associated with poorly-managed diabetes mellitus. In this study, we report the effect of oral treatment with combined leaf extract (CLE) of neem and bitter leaf on the prefrontal cortex of diabetic Wistar rats. Adult male Wistar rats were randomized to one of the following groups: control, diabetic (STZ-induced), STZ + CLE, STZ + metformin and CLE only. At euthanasia, paraffin sections of the prefrontal cortex were stained with cresyl fast violet; while malondialdehyde (MDA) and glutathione peroxidase (GPx) were assayed in prefrontal homogenates. Oral CLE produced normoglycemia in the treated hyperglycaemic rats. Besides, Nissl-stained prefrontal sections showed no morphologic deficits in all the groups except the untreated diabetic rats. In the latter, there was weak Nissl staining, while prefrontal MDA was significantly high at euthanasia, compared with the control and CLE-treated rats (P<0.05). This study showed that untreated diabetes mellitus is associated with prefrontal Nissl body deficit and oxidative stress in Wistar rats. The absence of these deficits in CLE-treated rats suggests a neuroprotective effect of the extract in streptozotocin-induced diabetic rats. This may improve the cognitive function of the prefrontal cortex in diabetes mellitus.

La disfunción cognitiva es presuntamente asociada con un mal manejo de la diabetes mellitus. En este estudio, se presenta el efecto del tratamiento oral combinado con extracto de hoja (CLE) de hoja de neem amarga sobre la corteza prefrontal de ratas Wistar con diabetes. Las ratas Wistar adultas fueron asignadas al azar a uno de los siguientes grupos: control, diabetes (STZ inducida), STZ + CLE, STZ + metformina y CLE. Después de la eutanasia, los cortes de parafina de la corteza prefrontal se tiñeron con violeta de cresil rápido, mientras que el malondialdehído (MDA) y la glutatión peroxidasa (GPx) fueron analizadas en homogenizados prefrontales. El CLE produce normoglucemia en las ratas hiperglucémicas tratadas. Además, las secciones prefrontales teñidas para Nissl no muestran ningún déficit morfológico en todos los grupos excepto en las ratas diabéticas sin tratamiento. En este último caso, hubo una tinción de Nissl débil, mientras que la MDA prefrontal fue significativamente más alta en comparación con los grupos de ratas control y las tratadas con CLE (p <0,05). Este estudio mostró que la diabetes mellitus no tratada se asocia con déficit prefrontal de cuerpos de Nissl y estrés oxidativo en ratas Wistar. La ausencia de estos déficits en las ratas tratadas CLE, sugiere un efecto neuroprotector del extracto en ratas diabéticas inducidas por estreptozotocina. Esto puede mejorar la función cognitiva de la corteza prefrontal en la diabetes mellitus.

Dietary restriction prevents diabetogenic effect of streptozotocin in mice.

The beneficial role of dietary restriction (DR) was studied in streptozotocin (STZ)-induced diabetes in mice. The DR mice exhibited the lower blood glucose (mg/dl) level as compared to ad libitum (AL) fed ones. After 3 months’ DR, STZ treatment to both AL and DR mice showed significant (p<0.001) elevation of the blood glucose level in AL-fed mice, while a lower level of glucose was maintained in DR-fed mice. The ability of maintaining a low blood glucose level in STZ-treated DR mice indicated that STZ might have been ineffective from its action on beta cells of pancreas by long-term DR. Thus, these findings suggested that DR may be an important tool for preventing the diabetic conditions. However, further studies are required to know the mechanism(s) of DR protection against diabetogenic action of STZ in experimental animals.

Altered liver morphology and enzymes in streptozotocin induced diabetic rats / Morfología y enzimas del hígado alteradas en ratas con diabetes inducida por estreptozotocina

This study was undertaken to evaluate the relationship and effects of diabetes on liver morphology, architecture and function. The hepatic effects of diabetes were evaluated in vivo using streptozotocin (STZ)-induced diabetic rats as an experimental model. The degree of hepatic dysfunction was measured by using biochemical parameters like serum transaminases (ALT and AST), alkaline phosphatase (ALP)and pseudocholinesterase (PChE) while the histopathological studies were carried out to support the enzymic Parameters. The aim of the study was to investigate the association between diabetic hepatic complications and liver enzyme alterations. This study was performed in the Department of Anatomy; Institute of Pharmaceutical Sciences and Institute of Diabetology and endocrinology of Baqai Medical University, Karachi. Diabetes was induced by a single dose of STZ (45 mg/kg, b.w.) given intraperitoneally in sodium citrate buffer at pH 4.5. Eighty albino rats were divided into five groups: control (A) and STZ treated (B, C, D, and E) which were sacrificed 2, 4, 6 and 8 weeks post treatment respectively. Histopathological examination of liver showed accumulation of lipid droplets, lymphocytic infiltration, increased fibrous content, dilatation and congestion of portal vessels and proliferation of bile ducts. Increased levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), ALP and PChE were observed in the liver. It seems that the diabetic complications in the liver like hepatocyte destruction etc. are likely to be due to alterations in enzyme levels.

Este estudio se realizó para evaluar la relación y los efectos de la diabetes sobre la morfología, arquitectura y la función del hígado. Los efectos hepáticos de la diabetes se evaluaron in vivo utilizando estreptozotocina (STZ) para inducir diabetes en ratas como un modelo experimental. El grado de disfunción hepática se midió mediante el uso de parámetros bioquímicos, como las transaminasas séricas (ALT y AST), fosfatasa alcalina (ALP) y pseudocolinesterasa (PChE), mientras que los estudios histopatológicos se llevaron a cabo para apoyar los parámetros enzimáticos. El objetivo del estudio fue investigar la asociación entre las complicaciones hepáticas diabéticas y la alteración de enzimas hepáticas. Este estudio se realizó en el Departamento de Anatomía, Instituto de Ciencias Farmacéuticas y el Instituto de Diabetología y Endocrinología de la Baqai Medical University, Karachi. La diabetes fue inducida por una dosis única de STZ (45 mg/kg de peso corporal) administrada por vía intraperitoneal en tampón citrato de sodio a pH 4,5. Ochenta ratas albinas se dividieron en cinco grupos: control (A) y tratados con STZ (B, C, D y E), las que se sacrificaron a las 2, 4, 6 y 8 semanas después del tratamiento. El examen histopatológico de hígado mostró acumulación de gotitas de lípidos, infiltración linfocítica, aumento del contenido de fibras, dilatación y congestión de los vasos portales, y la proliferación de conductos biliares. Aumento de los niveles de aspartato aminotransferasa (AST), alanina aminotransferasa (ALT), ALP y PChE fueron observados en el hígado. Parece que las complicaciones de la diabetes en el hígado como la destrucción de los hepatocitos etc., son probablemente debido a alteraciones en los niveles de las enzimas.

Altered kidney morphology and enzymes in streptozotocin induced diabetic rats / Morfología y enzimas renales alteradas en ratas con diabetes inducida por estreptozotocin

We studied the effects of streptozotocin (STZ)-induced diabetes on kidney morphology, anatomy, architecture and on the activities of aminotransferases (AST and ALT), alkaline phosphatase (ALP) and pseudocholinesterase (PChE) in albino rats. The aim of the study was to investigate the association between diabetic kidney complications and kidney enzyme alterations. This study was performed in the Department of Anatomy and Institute of Pharmaceutical Sciences, Baqai Medical University, Karachi and Pathology department of College of Physicians & Surgeons (CPSP) Pakistan in 2007-08. Diabetes was induced by a single dose of STZ (45 mg/kg, b.w.) given intraperitoneally in sodium citrate buffer at pH 4.5. Eighty (80) albino rats were divided into five groups: control (A) and STZ treated (B, C, D, and E) which were sacrificed 2, 4, 6 and 8 weeks post treatment respectively. Histopathology of kidney showed lesions similar to human glomerulosclerosis, glomerular membrane thickening, arteriolar hyalinization and tubular necrosis. Increased levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and pseudocholinesterase (PChE) were observed in the kidney. It seems that the diabetic complications in the kidney are likely to be associated with alterations in enzyme levels.

Se estudiaron los efectos de la diabetes inducida por estreptozotocin (STZ) sobre la morfología, anatomía, arquitectura y sobre las actividades de aminotransferasas (ALT y AST), fosfatasa alcalina (ALP) y pseudocolinesterasa (PChE) en los riñones de ratas albinas. El objetivo del estudio fue investigar la asociación entre las complicaciones renales diabéticas y la alteración de las enzimas renales. Este estudio se realizó en el Departamento de Anatomía y el Instituto de Ciencias Farmacéuticas, Universidad de Medicina Baqai, Karachi y el departamento de Patología de Colegio de Médicos y Cirujanos (CPSP) Pakistán entre el 2007-2008. La diabetes fue inducida por una dosis única de STZ (45 mg / kg de peso corporal) administrada por vía intraperitoneal en tampón de citrato de sodio a pH 4.5. Ochenta (80) ratas albinas fueron divididas en cinco grupos: control (A) y STZ tratados (B, C, D y E), que se sacrificaron a las 2, 4, 6 y 8 semanas después del tratamiento, respectivamente. La histopatología del riñón mostró lesiones similares a la glomeruloesclerosis en humanos, engrosamiento de la membrana glomerular, hialinización arteriolar y necrosis tubular. Aumento de los niveles de aspartato aminotransferasa (AST), alanina aminotransferasa (ALT), fosfatasa alcalina (ALP) y pseudocolinesterasa (PChE) fueron observados en el riñón. Parece que las complicaciones de la diabetes en el riñón están directamente asociadas con alteraciones en los niveles de las enzimas.

Analysis of myenteric neurons of the cecum of diabetic rats after supplementation with ascorbic acid / Análisis de neuronas mientéricas del ciego de ratas diabéticas después de suplementación con ácido ascórbico

The objective of this work was to investigate the neuroprotective action of the ascorbic acid over the myenteric neurons in the cecum of Wistar rats, four months after induction of the diabetes mellitus experimental with streptozotocin. Three groups with five rats each were used: C- controls, D- diabetic, DA- diabetic treated with ascorbic acid. For evidentiation of the myenteric neurons was carried out to Giemsa's technique. Were evaluated the areas of cell bodies of 500 neurons in each group studied. The quantitative analysis was carried out in an area of 16.6 mm2 in each cecum studied. In the animals diabetic observed elevation of the glycemia and glycated hemoglobin. The supplementation with ascorbic acid was effective under the myenteric neurons of the cecum of diabetics rays, since was presented the effect neuroprotective and neurotrofic.

El objetivo de este trabajo fue verificar el efecto neuroprotector del ácido ascórbico sobre las neuronas mientéricas en el ciego de Rattus Wistar, cuatro meses después de la inducción de diabetes mellitus experimental con estreptozotocina. Utilizamos tres grupos de animales: C- control, D- diabético, DA- diabético tratado con ácido ascórbico. Para la observación de las neuronas mientéricas fue llevado a cabo la técnica de Giemsa. Fueron evaluadas las áreas del soma de 500 neuronas, en cada grupo estudiado. El análisis cuantitativo fue llevado a cabo, en cada ciego, en un área de 16,6 mm². En los animales diabéticos, se observó la elevación de la glicemia y de la hemoglobina glicosilada. La suplementación con ácido ascórbico fue efectiva en las neuronas mientéricas del ciego de animales diabéticos, ya que se produjeron los efectos neuroprotetor y neurotrófico.

Renal microvascular changes in streptozotocin-induced, long-termed diabetic rat.

OBJECTIVE: To investigate the renal microvascular changes in streptozotocin (STZ)-induced, long-termed diabetic rat. MATERIAL AND METHOD: Twelve male Sprague-Dawley rats were used. Each diabetic rat (n = 8) was induced by an intraperitoneal injection of STZ (60 mg/kg) in citrate buffer (pH 4.5). Control rats (n = 4) were injected intraperitoneally with the same amount of the buffer. The animals were sacrificed at 20 weeks after the injections. The kidneys were processed for conventional light microscopy (LM) and vascular corrosion cast technique with scanning electron microscopy (SEM). RESULTS: Under LM, it was found that the glomerular sizes intensively decreased in the long-termed diabetic rat. The thickening of Bowman's basement membrane was demonstrated. Additionally, there were macrophages and capsular drop lesions in renal corpuscles of long-termed diabetes. The sizes of proximal and distal tubules were markedly destroyed, when compared to the control. Moreover, the epithelial necrosis of vacuolated renal tubules was observed. By using vascular corrosion cast with SEM, the glomerular microvascular sizes in the long-termed diabetes were significantly decreased that corresponded to the result under LM. Furthermore, the size of peritubular capillaries decreased. Concerning to vasa recta in the long-termed diabetes, these vessels ran tortuously and decreased in size. CONCLUSION: Renal microvascular changes, observed in STZ-induced diabetic rats, mimic human diabetic nephropathy (DN). Additionally, the pathological changes of the renal tubules were investigated. Therefore, the present study provides an important basic knowledge for understanding the processes in developing DN, as well as for further study of the therapeutic treatment.

Acute hypoglycemic, hypocholesterolemic and hypotriglyceridemic effects of continuous intravenous infusion of a lyophilised aqueous extract of Ajuga iva l. Schreber whole plant in streptozotocin-induced diabetic rats

The hypoglycemic and hypolipidemic effect of continuous intravenous infusion of a lyophilised aqueous extract of the whole plant Ajuga iva [L.] Schreber [Labiatae] [Al-extract] was investigated in anesthetized normal and streptozotocin [STZ]-induced diabetic rats. The Al-extract was administered to a group of rats by continuous intravenous infusion for 4 h at a dose of 4.2 microg/min/l00g body weight; another group was infused with taurine, the reference compound, at the same dose. In normal rats, Al-extract infusion had no effect on plasma glucose or triglycerides, but plasma cholesterol levels were significantly decreased [22%; P<0.05]. However, taurine infusion produced significant hypoglycemic, hypocholesterolemic and hypotriglyceridemic effects [all changes, P<0.05]. In STZ-diabetic rats, Al-extract infusion reduced plasma levels of glucose by 24% [P<0.05], cholesterol by 35% [P<0.01] and triglycerides by 13% [P<0.05]. Infusion with taurine produced a greater fall in plasma glucose [72%, P<0.01], cholesterol [54%; P < 0.001] and triglyceride [24%; P < 0.001] levels. Our results indicate that intravenously administered Al-extract exerts hypoglycemic and hypolipidemic effects in diabetic rats by mechanism [s] which appear to be similar to that of taurine, which involve insulin sensitization or an insulin-like effect. The identity and the exact mechanism [s] of action of the active component [s] of the Al-extract are not known. Ajuga iva appears to be a useful plant in the therapy of diabetes, a condition in which hyperglycemia and dyslipidemia coexist quite often

effect of oral administration of chard on contractile reactivity of isolated aorta in diabetic rats

Chard [Beta vulgaris L. var. Cicla] administration could improve the activity of antioxidant systems such as gluthatione and has a hypoglycemic and hypolipidemic property. To evaluate the effect of oral administration of chard on the contractile reactivity of isolated aorta in diabetic rats. This experimental study was conducted at the School of Medicine, Shahed University in 2003. Male Wistar rats were divided into control, chard-treated control, diabetic, and chard-treated diabetic groups. For induction of diabetes, streptozotcin [STZ] was intraperitoneally administered [60 mg/Kg]. Chard-treated groups received chard mixed with standard pelleted food at a weight ratio of 1/15. After one month, contractile reactivity of aortic rings to KC1 and noradrenaline was determined using isolated tissue setup. Serum glucose level showed a significant increase [409/4 and 401/3 mg/dl] in diabetic group at 2[nd] and 4[th] weeks [P<0.001], while this increase was less obvious in chard-treated diabetic group [274/5 and 161/2 mg/dl] [P<0.01 and P<0.001 for 2[nd] and 4[th] weeks, respectively]. In addition, the latter group showed a lower contraction to KC1 [P<0.05] and noradrenaline [P<0.01] as compared to diabetic group [0/76 and 1.41 g/mm [2] of the aortic ring]. Meanwhile, there was no significant difference between control and chard-treated control groups regarding contractile reactivity. Oral administration of chard for one month could attenuate the contractile responsiveness of the vascular system and may prevent the development of hypertension in diabetic rats

Effects of exercise training on autonomic and myocardial dysfunction in streptozotocin-diabetic rats

Several investigators have demonstrated that diabetes is associated with autonomic and myocardial dysfunction. Exercise training is an efficient non-pharmacological treatment for cardiac and metabolic diseases. The aim of the present study was to investigate the effects of exercise training on hemodynamic and autonomic diabetic dysfunction. After 1 week of diabetes induction (streptozotocin, 50 mg/kg, iv), male Wistar rats (222 +/- 5 g, N = 18) were submitted to exercise training for 10 weeks on a treadmill. Arterial pressure signals were obtained and processed with a data acquisition system. Autonomic function and intrinsic heart rate were studied by injecting methylatropine and propranolol. Left ventricular function was assessed in hearts perfused in vitro by the Langendorff technique. Diabetes (D) bradycardia and hypotension (D: 279 +/- 9 bpm and 91 +/- 4 mmHg vs 315 +/- 11 bpm and 111 +/- 4 mmHg in controls, C) were attenuated by training (TD: 305 +/- 7 bpm and 100 +/- 4 mmHg). Vagal tonus was decreased in the diabetic groups and sympathetic tonus was similar in all animals. Intrinsic heart rate was lower in D (284 +/- 11 bpm) compared to C and TD (390 +/- 8 and 342 +/- 14 bpm, respectively). Peak systolic pressure developed at different pressures was similar for all groups, but +dP/dt max was decreased and -dP/dt max was increased in D. In conclusion, exercise training reversed hypotension and bradycardia and improved myocardial function in diabetic rats. These changes represent an adaptive response to the demands of training, supporting a positive role of physical activity in the management of diabetes.

Effects of some antioxidants on induction and course of streptoztocin-induced diabetes mellitus in albino rats

Blood glucose, serum insulin and C-peptide levels were determined as parameters of diabetic status and pancreatic beta cell functions. The antioxidants were administered daily orally to sixty-five male rats with weight ranging 170-200 g for ten days prior to induction of diabetes mellitus. Most of the studied antioxidants produced a highly significant low blood glucose compared with thirteen control diabetic rats. Blood glucose level [mean +/- SD] was 469.5 +/- 37.8 mg/dl in the control group compared with 365 +/- 36.1 mg/dl in vitamin C group, 379.9 +/- 42.0 mg/dl in vitamin E group, 179.3 +/- 28.7 mg/dl in combination group and 184.5 +/- 19.1 mg/dl in the melatonin group. The serum insulin and C-peptide levels were significantly higher in the antioxidants groups than the control group. The study also investigated the effects of the antioxidants on attenuation of the diabetic status. For this aim, another five groups of rats [ten each] with established induced diabetes mellitus were given the above- mentioned antioxidants for four weeks and compared with ten control diabetic rats. The study observed favorable significant effects on the blood glucose, serum insulin and C-peptide levels in the groups receiving the antioxidants. The results also demonstrated preventive and potential therapeutic effects of antioxidants on the streptozotocin-induced diabetes mellitus in albino rats

Diabete e gravidez experimental em ratas: I. Induçäo do diabete, obtençäo e evoluçäo da prenhez / Diabetes and experimental pregnancy in rats: I. Diabetes induction, pregnancy obtention and evolution

O objetivo deste trabalho foi o desenvolvimento do modelo experimental em ratas para estudo do binômio diabete e gravidez. O experimento foi em 4 períodos: de adaptaçao (7 dias), diabetogênico (15 dias), de acasalamento (l5 dias) e de prenhez (21 dias). Utilizou-se 275 ratas da raça "Wistar", fêmeas virgens, pesando entre 180 e 25Og, em idade reprodutiva. O diabete induzido com aloxana, na dosagem de 42 mg/kg de peso, originou dois grupos: moderado (glicemia entre 120 e 2OOmg/dl) e grave (glicemia 200 mg/dl). A induçao com streptozotocin, 40 mg/kg de peso, IV, resultou apenas um grupo com diabete grave. O grupo controle foi constituído por ratas prenhes e nao diabéticas (glicemia 120 mg/dl). Nos períodos diabetogênico e de acasalamento os animais dos grupos diabéticos foram arranjados em dois subgrupos que receberam ou nao insulina diária por via SC, até a confirmaçao da prenhez. Níveis glicêmicos plasmáticos maternos e fetais foram avaliados no 21( dia da prenhez e, a glicemia fetal, obtida por um "pool" da ninhada, colhido logo após a cesárea, sob anestesia com éter, na manha desse dia. Os resultados demonstraram que o modelo experimental é adequado para o estudo proposto. As drogas utilizadas foram eficazes, tendo o streptozotocin a vantagem de ser dose-dependente e menos tóxico. A insulinoterapia diminuiu a mortalidade no período diabetogênico e melhorou o índice de prenhez diabética, que se caracterizou por elevada incidência de abortamento e morte materna. A glicemia fetal correlacionou-se com a materna refletindo os níveis glicêmicos aos quais o feto se submeteu durante a prenhez.

Relación entre las lesiones electrolíticas del núcleo hipotalámico ventromedial y la diabetes mellitus insulino dependiente inducida por streptozotocina

Dada la función reguladora del sistema nervioso sobre el endocrino se busca analizar la correlación entre la lesión del núcleo hipotalámico ventromedial (HVM) y la severidad de la diabetes inducida por estreptozotocina (STZ). Se utilizan 29 ratas divididas en cuatro grupos: Grupo I: lesión del HVM e inyección de SS (murieron por complicaciones respiratorias); Grupo III: lesión del HVM e inyección de STZ; Grupo IV: lesión ficticia del HVM e inyección de STZ. Se observan por un período de 6 a 8 semanas. Se exploran semanalmente valores de química sanguínea como glicemia, colesterol y triglicéridos y se mide el peso corporal; cada dos días se determina el consumo de agua y en el momento del sacrificio se pesa la grasa perirrenal y se fijan los cerebros para determinar tamaño y sitio de la lesión. Los resultados muestran que el grupo III es el más afectado en cuanto a severidad de la diabetes y velocidad de deterioro de los animales; mientras que el grupo I sólo muestra aumento de peso corporal pero sin evidencia de diabetes. Todo parece indicar que el aumento de la ingesta inducido por la lesión del "núcleo de la sacidad" y por la misma diabetes produce efectos aditivos sobre el cuadro patológico

Modelo diabético en ratas / Diabetic model in rats

Durante los meses de junio a noviembro de 1983, se estudian en el Instituto de Endocrinología los efectos del monohidrato de aloxán, la estreptozotocina y la pancreatectomía parcial asociada a estreptozotocina para provocar diabetes en un grupo de ratas Wistar. Se describen los resultados y se revisa la literatura a nuestro alcance