Endogenic non-enzymatic antioxidative system of polyester grafts during their healing.
OBJECTIVE: Non-enzymatic low-molecular antioxidants are one of the important mechanisms which protect cells against the toxic effect of oxygen. The aim of the present study was to determine the content of glutathione, glutathione reductase, and ascorbic acid in the principal layers of polyester grafts. INTERVENTIONS AND MEASURES: The experiments were carried out on 24 mongrel dogs, in which polyester double velour DALLON grafts were implanted. Seven days, 1, 4, and 12 months after the operation the grafts were excised. The following were determined: glutathione content by use of a GSH-400 system, glutathione reductase activity by the method of Langdon and Mize, and ascorbic acid content by the Kyaw method. RESULTS: It was found that the glutathione content in the graft neointima was 33% lower, in the graft neomedia higher during the first 4 months, in the neoadventitia 50% lower after 4 months than in the corresponding layers of the aorta (p < 0.01). The activity of glutathione reductase was significantly higher in all the graft layers during 12 months' observation than in the normal aorta layers. The ascorbic acid content of the graft layers was lowest 7 days after the implantation, and then in time increased so that 12 months after the operation it reaches its highest values. CONCLUSIONS: Our study shows that low non-enzymatic antioxidative potential is not capable of proteoting the newly forming graft layers, particularly the neointima, against oxygen toxicity. Thus, it would be beneficial to administer antioxidants (vitamin C, vitamin E, and N-acetylcysteine).