Plasma antioxidants and lipid peroxidation products in Duchenne muscular dystrophy.

Lipid peroxidation (LPX) products in plasma were elevated in Duchenne muscular dystrophy (DMD) patients (n = 9) compared with an age- and sex-matched group of controls (n = 10). Trichloroacetic acid-precipitable thiobarbituric acid-reactive substances (TBARS) were increased by 35% (p less than 0.01), conjugated dienes by 77% (p less than 0.02) and fluorescent pigments (FP) by 70% (p less than 0.001). Plasma alpha-tocopherol was significantly decreased, by 50%, in DMD compared with healthy subjects (p less than 0.002). In conjunction with the finding of others of a deficiency in DMD of the plasma lipoproteins which normally transport vitamin E to the tissues, this may contribute to the increased LPX seen in the disease especially if muscle damage also liberates free Fe2+. The major circulating antioxidant protein, caeruloplasmin (CP), was significantly increased (p less than 0.001) by 25-30% in DMD patients compared with both adult and young male controls. In DMD patients only, this increase is correlated with the concentration of TBARS and FP suggesting that increased LPX may be a trigger for CP synthesis.

The effects of propranolol on skeletal muscle contraction, lipid peroxidation products and antioxidant activity in experimental hyperthyroidism.

1. The mean levels of lipid peroxidation products, namely conjugated diene and malonaldehyde, were increased in the soleus muscles of hyperthyroid cats, while the mean glutathione peroxidase activity was decreased. No corresponding similar changes were noted in the fast extensor digitorum longus muscles and serum. 2. Propranolol administration prevented the increase in conjugated diene level in the soleus muscles of hyperthyroid cat but not the malonaldehyde level. It also prevented the reduction in glutathione peroxidase activity in the slow oxidative soleus muscles of hyperthyroid cats. 3. Maximal twitch tension, subtetanic tension and maximum tetanic tension of soleus and EDL muscles were reduced in hyperthyroid cats. Propranolol administration for 5 weeks to hyperthyroid cats did not prevent the reduction in tension of contractions of these muscles. 4. It is suggested that lipid peroxidation might not be responsible for the myopathy in hyperthyroidism and propranolol administration does not improve skeletal muscle function in hyperthyroid animals.

Palm olein oil produces less lipid peroxidation products than soya bean oil.

The soleus muscles of hyperthyroid rats were used to investigate the effect of palm olein oil and soya bean oil on the production of lipid peroxidation products. It was found that palm olein oil but not soya bean oil significantly decreased malonaldehyde and conjugated diene levels of the soleus muscles of hyperthyroid rats. These findings suggest that palm olein per se produces less lipid peroxidation products than soya bean oil. Such an assay method gives a composite net picture of the propensity of an oil to produce lipid peroxidation products.