The in Vitro Effects of Captopril on the Levels of Lipid Peroxidation and Glutathione of Erythrocytes in Type ll Diabetics

Authors: Yüksel ALTUNTAŞ, Mehmet GÜVEN, Erdal İNCE, Özer AÇBAY, Metin CANER, Gönül KANIGÜR-SULTUYBEK, Hüsrev HATEMİ

Abstract: The increase in lipid peroxidation (LP) is an indirect marker of free radical activation. The products of LP (malonyldialdhyde: MDA) are increased in diabetic patient, particularly those with angiopathy. In this study, the invitro effect and the mechanism of action captopril, an angiotensin converting enzyme (ACE) inhibitor, on lipid peroxidation in diabetics is investigated. For this purpose, MDA and gulutathione levels are studied in erythrocytes of 9 type ll diabetics (NIDDM) (mean age: 57±10 yrs, duration of diabets: 12±6 yrs) and 10 healthy subjects (mean age: 30±5 yrs). The level of lipid peroxides was expressed as MDA release (MDA%). MDA in erythrocytes of type ll diabetics has been decreased by the effect of increasing concentrations of captobril (before:19.47±2.80, after captopril: (2x10-5M) 14.21±3.20 MDA%; (4x10-5 M)12.14±3.29MDA%; (6x10-5M) 11.53±2.72 MDA%; (10x10-5M) 10.57±2.09 MDA%). In control group, there is a little decrease in LP after preincubation with captopril from 2 to 6x10-5 M captopril (p>0.05), but 10x10-5M concentration reduced the lipd peroxidation (p>0.05), but 10x10^{-5}M concentration reduced the lipid peroxidation (p<0.01). However, after preincubated with captopril, gluttathione level did not change significantly in the diabetic and normal erythrocytes. In our study, the high levels of lipid peroxidation in erythrocytes from diabetic patients was decreased with preincubation with captopril. Decreasing in the level of lipid peroxidation in vitro was independent on the glutathione level. The reason of this decreasing of the lipid peroxadation may suggest that crosling binding between MDA and captopril. As result, captopril may also normalize high levels of lipid peroxidation by a mechanism which is not related to its free radical scavenging capacity in vitro.

Keywords: Lipid peroxidation, Glutathione, Captopril, Type ll diabetes, Erythrocyte