Pathogenesis of cardiovascular disorders in streptozotocin-induced diabetes in rat. II. Correlation between lipid peroxides, thromboxane A2/prostacyclin, and platelet aggregation in different stages of diabetes.

An attempt was undertaken to assess the relationship between the imbalance of lipid peroxides, thromboxane A2/prostacyclin and increased platelet aggregability during early (2 months) and late (6 months) stage of streptozotocin diabetes in rat. Thromboxane A2 and prostacyclin (PGI2) were estimated by their stable metabolic products TXB2 and 6-keto-PGF1 alpha respectively. The results showed: 1. There is a significant imbalance in TXA2 (a potent promoter of platelet aggregation) and PGI2 (a potent vasodilator and inhibitor of platelet aggregation). The ratio TXA2/PGI2 was increased by 38% in the early and by 69% in the late stage of diabetes. 2. Serum lipid peroxides increased significantly during early (four times) and late (five times) stage of diabetes. 3. There is a very good correlation between increased lipid peroxides and increased TXA2/PGI2 ratio (r = 0.71) in diabetic rats. 4. A pronounced increase in thrombin-induced platelet aggregation is consistent with the increased levels of lipid peroxides (r = 0.65) and TXA2/PGI2 ratio (r = 0.60). 5. All described changes correlate with the duration of the disease.