Morphological effects of rapeseed oil in rats. I. Short-term studies.

Light microscopy of paraffin embedded and frozen sections, supplemented with electron microscopy, was performed on the heart muscle of young rats fed rapeseed oil in short-term experiments. It was confirmed that high levels of rapeseed oil, which contains erucic acid, produce severe lipoidosis of the heart muscle fibres within 10 days. An attempt was made to find out the lowest level of erucic acid in the rat diet to give rise to pathological fatty accumulation. Several frozen sections from each heart or serial sections in combination with electron microscopy were used for this evaluation. The level found to give rise to pathological fatty accumulation was about 2% by weight (w/w), while rats fed 1% erucic acid showed normal myocardium. No direct proof that erucic acid is of importance in human pathophysiology has hitherto been presented. It is concluded, however, that the similarity in reaction among the many species of experimental animals tested by different workers, as well as the basic metabolic disturbances demonstrated, are in strong favour of a similar effect in man.