Enzyme histochemical studies on microarterial grafts in rats

In order to evaluate the duration and localization of the metabolic changes elicited by the procedure of transplantation, the sequential changes in enzymatic activity of carotid artery grafts in rats were evaluated by histochemical demonstration of the activity of two oxidoreductases, lactate dehydrogenase (LD) and succinate dehydrogenase (SD), and two hydrolytic enzymes, adenosine triphosphatase (ATPase) and alkaline phosphatase (AFOS). The most intense staining for ATPase, LD and SD was seen in the media, both in the grafts and in the adjacent carotid artery. The activity of AFOS was concentrated to the inner parts of the adventitia. The medial layer of the microarterial graft showed no obvious changes in enzyme activity during the observation period of four weeks. At the anastomoses, LD and SD showed decreased activity from day one onwards. No intimal thickening or other clear structural changes were seen in the grafts.