Effect of vasectomy on serum lipids, platelet aggregability and development of ischaemic heart disease in rhesus monkeys.

In this study the long term effects of vasectomy on serum lipid profile, in vitro platelet aggregability and the risk of developing acute myocardial infarction have been elucidated in a monkey model. Four groups were made viz. (I) atherogenic diet fed vasectomised, (II) atherogenic diet fed control, (III) stock diet fed vasectomised and (IV) stock diet fed control. The respective diets were fed for first 6 months and then half of the atherogenic and stock diet fed monkeys were bilaterally vasectomised. The remaining monkeys were sham-vasectomised. At the end of one year, norepinephrine infusion was given to all the monkeys each day for 2 hrs, for 3 consecutive days and animals sacrificed after 96 hrs. Although serum lipids were not altered following vasectomy, platelet aggregation response was significantly enhanced in atherogenic diet fed animals. ECG changes were suggestive of acute myocardial ischaemia in 4 monkeys, 2 each from gp. I and II. Histopathology of heart revealed patchy myocardial necrosis and haemorrhage only in one monkey of gp. I, while others had fuchsinorrhagia indicating ischaemic change. These findings are in contrast to those seen in vasectomised human subjects.