Atherosclerosis Elsevier Publishing Company, Amsterdam - Printed in The Netherlands 301 Short Communications EXPERIMENTAL ATHEROSCLEROSIS INDUCED BY MECHANICAL TRAUMA IN RATS G. BOND JERS AND T. BJORNHEDEN Department of Histology, University of Gdteborg, GBteborg (Sweden) (Revised, received February 12th, 1970) SUMMARY To investigate if mechanical trauma might induce atherosclerosis in the rat, defects in the aorta were created. After weak trauma, transient intimal thickenings developed. The arterial wall structure was restored after 8 weeks. After strong trauma, non-regressive lipid-rich intimal thickenings developed, very similar to early human atherosclerotic lesions. Key words: Atherosclerosis-like lesions - Experimental atherosclerosis - Mechanical trauma - Rats INTRODUCTION Recently it has been shown that atherosclerosis develops in the rabbit after a specific type of mechanical trauma a. The present study was undertaken to elucidateif this type of mechanical trauma might also induce atherosclerosis in the rat, which is very resistant to dietary induced experimental atherosclerosislJ. MATERIALS AND METHODS Twenty-two Sprague-Dawley rats were obtained from the same source. They were fed ad libittim on a standard rat diet (AB Teknosan, Malmii, Sweden). Mechanical damage was induced by an instrument constructed as described by BJ~RKERUD*. The size of the instrument was adjusted to fit the rat. An 0.63 mm This work has been supported by the Swedish National Association against Heart and Chest Diseases. Atherosclerosis, 1970, 12: 301-306