The effect of silymarin (SMN) in reducing metabolic risk factors and amelioration of cardiac apoptosis in an experimental model of diabetes was investigated. Streptozotocin (STZ) was injected into male rats (50 mg/kg, ip), and after diabetic induction SMN (80mg/kg) was orally administered for 21 days. Diabetic rats showed a significant decrease in insulin level, hyperglycemia, elevated HOMA-IR, glycosylated hemoglobin (HBA1c), and lipid profile. A significant increase in the lipid peroxidation product malondialdehyde (MDA) and a decrease in the glutathione (GSH) concentration were demonstrated in the heart of the diabetic rats. A significant increase in the activities of creatin kinase-MB (CK-MB) and lactate dehydrogenase (LDH), aspartate amino transferase (GOT), alanine amino transferase (GPT) in the serum of the diabetic rats were demonstrated. Increased numbers of apoptotic cells with down-regulation of Bcl-2 and activation of Bax as well as the caspases-9 and 3 were demonstrated in the diabetic rats. SMN treatment of the diabetic rats ameliorated hyperglycemia, HBA1c, increased insulin secretion, improved HOMA-IR and lipid profile. SMN significantly increased serum HDL. SMN also blunted the increase in MDA and stimulated the GSH production in the heart of STZ-treated rats and improvedredox state. SMN enhanced Bcl-2 expression, blocked the increase of Baxand the caspases 9 and 3. This study demonstrates the effectiveness of SMN in ameliorating myocardial injury in experimental diabetes. This may be related to its antioxidative and anti-apoptotic properties and can be used as antidiabetic complement in case of diabetes mellitus to avoid cardiac complications.

antioxidants, apoptosis, oxidative stress, glutathione