Superoxide dismutase functional regulation in neonatal hypoxia: Effect of glucose, oxygen and epinephrine.

Hypoxia is one of the major causes of damage to the fetal and neonatal brain and cardiac functions. In earlier studies, we have reported the brain damage caused by hypoxia and resuscitation with oxygen and epinephrine and have found that glucose treatment to hypoxic rats and hypoxic rats treated with oxygen shows a reversal of brain damage. The neonatal rats are shown to be deficient in free radical scavenging system, which offers a high risk of oxidative stress. In the present study, we induced hypoxia in neonatal Wistar rats and resuscitated with glucose, oxygen and epinephrine. Heart tissue and cerebral cortex were used to study the kinetics of superoxide dismutase activity in experimental groups of rats to assess the free radical status. Results showed that glucose supplementation in hypoxia (Hx + G) and hypoxic + oxygen (Hx + O) had an efficient free radical scavenging capability, compared to all other experimental groups. The observation was ascertained by studying the activity of catalase, another antioxidant enzyme in the body. Our results suggested that in neonatal rats during hypoxic condition, damage to heart and brain was more prominent in all groups, except when supplemented with glucose. These findings may have clinical significance in the proper management of heart and brain function.

Polyunsaturated fatty acids (PUFA) regulate neurotransmitter contents in rat brain.

The effects of feeding of 6-propylthiouracil (6-PTU) and polyunsaturated fatty acids (PUFA) independently and in combination and administration (ip) of a single dose of triiodothyronine (T3) (2.5 microg/100 g body wt) along with feeding of 6-PTU and PUFA were studied in rat brain. Dopamine (DA), 5-hydroxytryptophan (5-HTP), serotonin (5-HT), 5-hydroxy indole acetic acid (5-HIAA), norepinephrine (NE) and epinephrine (EPI) contents were assayed in the hypothalamus and cerebral cortex regions. It was found that 6-PTU feeding resulted in decrease in dopamine, 5-HT, 5-HTP and 5-HIAA in both regions. In animals fed with PUFA followed by administration of T3, the DA level was found normal.

Kinetic studies of purified malate dehydrogenase in liver of streptozotocin-diabetic rats and the effect of leaf extract of Aegle marmelose (L.) Correa ex Roxb.

The functional basis of diabetes-mellitus to a certain extent, can be elucidated by studying diabetes-induced changes in metabolic enzymes. Malate dehydrogenase (MDH), is an enzyme directly involved in glucose metabolism. The kinetic parameters of MDH and its purified cytosolic isozyme, S-MDH, have been studied in the liver of streptozotocin-diabetic rats; also the potential of the leaf extract of A. marmelose as an anti-diabetic agent was investigated. The Km of the liver enzyme increased significantly, in both crude and purified preparations in the diabetic state when compared to the respective controls. Insulin as well as leaf-extract treatment of the diabetic rats brought about a reversal of Km values to near normal. Vmax of purified S-MDH was significantly higher in the diabetic state when compared to the control. Insulin and leaf extract treatment did not reverse this change. Since MDH is an important enzyme in glucose metabolism, the variation in its quantitative and qualitative nature may contribute to the pathological status of diabetes. The fact that leaf extract of A. marmelose was found to be as effective as insulin in restoration of blood glucose and body weight to normal levels, the use of A. marmelose as potential hypoglycemic agent is suggested.

Effect of leaf extract of Aegle marmelose (L.) Correa ex Roxb. on histological and ultrastructural changes in tissues of streptozotocin induced diabetic rats.

Light and electron microscopic examination of tissues of rats rendered diabetic with a smaller dose of 45 mg/kg of body weight of streptozotocin were carried out in the present study. The dose of the drug given altered the function of pancreatic beta-cells and the acinar cells. The changes in the acinar cells were coarsening of endoplasmic reticulation (ER) and alterations in their secretory function. The changes in the liver were (1) dialation of veins, (2) loss of usual concentric arrangement of hepatocytes, (3) liver fibrosis and (4) decrease in glycogen content. The kidney tubules were thickened and the glomerulus was expanded. The leaf extract of Aegle marmelose reversed the altered parameters to near normal. The treatment of leaf extract on diabetic pancreas showed improved functional state of pancreatic beta-cells. The results indicate the potential hypoglycemic nature of the leaf extract, helping in regeneration of damaged pancreas.

Effect of leaf extract of Aegle marmelose in diabetic rats.

Alloxan induced animal model was used to evaluate the potential antidiabetic effect of A. marmelose leaf extract. The diabetic animals were given insulin injection and another group A. marmelose leaf extract orally. It maintained the weight of the animals near to the control rats but a significant decrease in weight was noted in diabetic animals without any treatment. The blood glucose level in treated animals were near to that of control ones. Also a significantly increased glucose tolerance was observed in animals orally given the leaf extract prior to the experiment. A significant decrease in liver glycogen (1.24 +/- .07 g/100 g of wet tissue) was observed in diabetic rats which was brought to almost the normal level (1.84 +/- .14 g/100 g) with leaf extract treatment. Blood urea and serum cholesterol increased (62.66 +/- 3.50 and 192.67 +/- 13.64 mg/dl) significantly in alloxan diabetic rats. The leaf extract treatment decreased the blood urea and serum cholesterol (37.83 +/- 3.97 and 99.20 +/- 8.43 mg/dl) to that of control ones. A similar effect was seen with insulin treatment. The results indicate that the active principle in A. marmelose leaf extract has similar hypoglycaemic activity to insulin treatment.