Effects of continuous administration of dietary theobromine on rat testicular weight and morphology

Abstract

Previous studies have shown that high dietary theobromine levels fed to rats results in testicular atrophy with changes in testicular cytology. An experiment was performed to determine whether these changes in rat testes are reversible. Proven breeder male rats were fed Purina lab chow containing 0, 0.2, 0.6, or 0.8% theobromine for 49 days. At that time, unilateral orchiectomy was performed on all rats. Testicular weights in the rats fed 0.6 and 0.8% theobromine-containing diets were significantly less than those from control rats and from rats fed 0.2% dietary theobromine ( p < 0.01). The seminiferous tubules from rats fed the 0.6 or 0.8% theobromine diets showed extensive severe cellular degeneration and necrosis and contained many multinucleated cells. The interstitial tissue was edematous and there was evidence of apparent proliferation of arterioles. The rats were allowed to recover and were fed the diet without theobromine for an additional 49 days. Testicular weights of the rats given 0.6 and 0.8% dietary theobromine in the first 49-day period remained significantly below those of control rats and of rats fed 0.2% dietary theobromine ( p < 0.01). Histologically, 70 to 90% of the seminiferous tubules from the rats given the two highest dietary levels of theobromine appeared almost deplete of well-formed spermatozoa. These results indicate that the theobromine-induced testicular injury appears to be irreversible over time in the affected seminiferous tubules.