Effects of chronic treatment with lisinopril on cardiovascular complications in streptozotocin diabetic and DOCA hypertensive rats.

The present study was undertaken to study the effects of chronic treatment with lisinopril on the cardiovascular complications in streptozotocin (STZ) diabetic and deoxycorticosteroneacetate (DOCA) hypertensive rats. Injection of STZ produced severe glycosuria (> 2%), hyperglycemia, hypoinsulnaemia, polydypsia, polyphagia and loss of body weight. It also produced hypothyroidism, hypercholesterolaemia, hypertriglyceridaemia, hypertension, bradycardia and decreased left ventricular developed pressure (LVDP). Elevation in serum creatinine level and increased activity of liver enzymes were also found in STZ treated animals. DOCA by itself did not produce any change in blood glucose but reduced serum insulin levels in non-diabetic animals. However, in the diabetic group, DOCA reduced blood sugar levels. Treatment of STZ-diabetic rats with DOCA did not aggravate cardiac depression or hyperglycaemia. Treatment of rats with lisinopril (1 mg kg-1, p.o. daily for six weeks), in diabetic and diabetic hypertensive animals prevented STZ induced loss of body weight and hypertension, bradycardia and hypothyroidism. It also prevented STZ induced hyperglycemia and hypoinsulinaemia in both diabetic and diabetic hypertensive animals. There was a reduction in cholesterol, triglyceride, and LDL levels; the ratio between total cholesterol to HDL and LDL to HDL and an improvement in LVDP at higher filling pressure in diabetic as well as diabetic hypertensive animals. Treatment with lisinopril also prevented hypertrophy and elevated levels of serum creatinine, SGOT and SGPT in diabetic animals. In conclusion, the present data suggests that STZ-DOCA model may not be considered as the ideal model for the study of cardiovascular complications of combined treatment hypertension and diabetes. However, the present investigation presents a number of beneficial effects of lisinopril treatment in diabetic with or without hypertensive rats and it may be considered as one of the drugs of choice in treatment of hypertension when it is associated with diabetes mellitus.