[Acute pancreatitis in the rat following experimental microembolism with cholesterol crystals]

Several case reports exist which demonstrate cholesterol crystals to be the cause of acute pancreatitis in humans. The crystals have been found intravascularly in the pancreas and at least in one case the origin of the crystals was known. We have undertaken to experimentally reproduce this pathogenetic mechanism in the rat. 30 rats were subjected to the following procedures: under anaesthesia the splenic artery was distally ligated and proximally cannulated; 16 control animals were injected via the cannula with saline (8 rats), particle free cholesterol saturated physiologic saline (3 rats) or nothing (5 rats). 14 rats were injected with ca. 400 microliters of a dilute suspension of cholesterol crystals of 5-40 microns diameter in cholesterol saturated physiologic saline. The abdomen was closed and after 24 h all animals were killed. Acute pancreatitis was diagnosed in all animals that received cholesterol microcrystals and in none of the controls. The diagnosis was based on macroscopic and histological findings. Acute pancreatitis was of focal, disseminated, necrotic type with oedema and moderate haemorrhage and fat necrosis. Only those parts of the pancreas were affected which were supplied by branches of the distal splenic artery used for retrograde injections of cholesterol crystals. This model supports the notion that microembolic or microthrombotic events play a pivotal role in the pathogenesis of spontaneous acute pancreatitis.