Alterações gastrointestinais no diabetes mellitus: estresse oxidativo e fluxo sangüíneo da artéria mesentérica - estudo experimental

The Treatment of Prednisone in Mild Diabetic Rats: Biochemical Parameters and Cell Response

Background:

Limited studies have been carried out with prednisone (PRED) in treatment by glucose intolerant individuals, even in this model the animals presented low blood glucose levels at adulthood, by the high regenerative capacity of β-cell.

Objective:

The aim was to evaluate the effects of the treatment of PRED in mild diabetes on biochemical and immunological biomarkers.

Methods:

Rats were randomly divided into four groups: control (C), treated control C+PRED (treatment of 1.25 mg/Kg/day PRED); diabetic DM (mild diabetes) and treated diabetic DM+PRED (treatment with same dose as C+PRED group). Untreated groups received vehicle, adjusted volume to body weight. The treatment lasted 21 days and measured body weight, food and water intake, and glycemia weekly. In the 3rd week, the Oral Glucose Tolerance Test (OGTT) and the Insulin Tolerance Test (ITT) was performed. On the last day, the rats were killed and the blood was collected for biochemical analyzes, leukogram and immunoglobulin G levels.

Results:

There was a significant decrease in body weight in mild diabetes; however, the treatment in diabetic groups increased food intake, glycemia, and the number of total leukocytes, lymphocytes and neutrophils. On the other hand, it decreased the levels of triglycerides, high-density and very lowdensity lipoproteins. In addition, diabetic groups showed glucose intolerance and mild insulin resistance, confirming that this model induces glucose intolerant in adult life.

Conclusion:

The results showed that the use of prednisone is not recommended for glucose intolerant individuals and should be replaced in order to not to aggravate this condition.

Effect of des-aspartate-angiotensin I on the actions of angiotensin II in the isolated renal and mesenteric vasculature of hypertensive and STZ-induced diabetic rats

The present study investigated the action of des-aspartate-angiotensin I (DAA-I) on the pressor action of angiotensin II in the renal and mesenteric vasculature of WKY, SHR and streptozotocin (STZ)-induced diabetic rats. Angiotensin II-induced a dose-dependent pressor response in the renal vasculature. Compared to the WKY, the pressor response was enhanced in the SHR and reduced in the STZ-induced diabetic rat. DAA-I attenuated the angiotensin II pressor action in renal vasculature of WKY and SHR. The attenuation was observed for DAA-I concentration as low as 10(-18) M and was more prominent in SHR. However, the ability of DAA-I to reduce angiotensin II response was lost in the STZ-induced diabetic kidney. Instead, enhancement of angiotensin II pressor response was seen at the lower doses of the octapeptide. The effect of DAA-I was not inhibited by PD123319, an AT2 receptor antagonist, and indomethacin, a cyclo-oxygenase inhibitor in both WKY and SHR, indicating that its action was not mediated by angiotensin AT2 receptor and prostaglandins. The pressor responses to angiotensin II in mesenteric vascular bed were also dose-dependent but smaller in magnitude compared to the renal vasculature. The responses were significantly smaller in SHR but no significant difference was observed between STZ-induced diabetic and WKY rat. Similarly, PD123319 and indomethacin had no effect on the action of DAA-I. The findings reiterate a regulatory role for DAA-I in vascular bed of the kidney and mesentery. By being active at circulating level, DAA-I subserves a physiological role. This function appears to be present in animals with diseased state of hypertension and diabetes. It is likely that DAA-I functions are modified to accommodate the ongoing vascular remodeling.