Administration of aqueous extract of Desmodium gangeticum (L) root protects rat heart against ischemic reperfusion injury induced oxidative stress.

Myocardial reperfusion is believed to be associated with free radical injury. The present study evaluates the effect of aqueous extract of D. gangeticum (DG) on lipid peroxides and antioxidants in ischemic reperfused (IR) Wistar albino male rats. Significant elevation in lipid peroxide products (thiobarbituric acid reactive substances) and decreased activity of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase) were observed in the rat hearts during ischemia reperfusion phase. Pre treatment of rats with aqueous extract of DG orally for 30 days showed significantly improved preservation of antioxidant enzymes and subsequent reduction in lipid peroxidation. But 2,3,5 triphenyl tetrazolium chloride (TTC) stained rat heart did not show much significant antioxidant enzyme activities and lipid peroxidation. On the other hand, TTC unstained rat heart showed significant improvement in the antioxidant activities indicating cardio protective effect of aqueous extract of DG in myocardium affected by ischemia reperfusion insult. The administration of DG to normal rats did not have any significant effect on any of the parameter studied. These results indicate that DG improves the antioxidant capacity of heart and attenuate the degree of lipid peroxidation after IR.

Effects of hypothyroidism induced by 6-n-propylthiouracil and its reversal by T3 on rat heart superoxide dismutase, catalase and lipid peroxidation.

The present study critically evaluates the effects of hypothyroid and hyperthyroid states on lipid peroxidation and two enzymes of active oxygen metabolism, namely superoxide dismutase (SOD) and catalase (CAT) in the rat heart mitochondrial and post-mitochondrial fractions. Lipid peroxidation, an index of oxidative stress, was elevated in the heart tissue in hypothyroid state but reduced upon T3 supplementation. Hyperthyroidism registered increased SOD activity in post-mitochondrial fraction. Mitochondrial SOD activity was reduced in hypothyroid state, which was further reduced by T3 administration. In contrast, different thyroid states had no effect on catalase activity in the mitochondrial fraction. The hypothyroid state however, significantly augmented catalase activity in post-mitochondrial fraction. The results suggest that the antioxidant defence status of cardiac tissue is well modulated by thyroid hormone.

Menor oxidación de cuerpos cetónicos por mitocondrias de corazón en la diabetes / Decreased oxidation of ketone bodies in heart mitochondrias in diabetes

Ratas diabéticas por inyección de estreptozotocina presentaron concentraciones de 3-hidroxibutirato y acetoacetato en sangre 4,2 y 1,7 veces superiores a las normales, respectivamente. Al mismo tiempo, en las mitocondrias de corazón disminuyó la actividad de las enzimas iniciadoras del metabolismo oxidativo de esos cuerpos cetónicos, a saber, la 3-hidroxibutirato deshidrogenasa (72%) y la succinil-CoA: acetoacetil-CoA (3 - oxoácido - CoA) transferasa (50%). En cambio, la acetoacetil-CoA tiolasa, no varió. La oxidación del 3-hidroxibutirato y el acetoacetato por las mitocondrias enteras de ratas diabéticas, suplementadas con ADP (en estado metabólico "3") disminuyó 42 y 48%, respectivamente, en relación a los testigos normales, no así la oxidación del piruvato o del L-glutamato más L-malato que no varió significativamente. Estas observaciones implican una modificación selectiva de las enzimas correspondientes a los cuerpos cetónicos. La composición lipídica y la depolarización de la fluorescencia del difenil hexatrieno en las mitocondrias diabéticas no presentaron diferencias respecto a las normales, de manera que las variaciones enzimáticas descriptas se pueden atribuir a una síntesis defectuosa de las proteínas mitocondriales