Objective  To investigate the expression and significance of big mitogen-activated protein kinase 1 (BMK1 or ERK5) in the pancreatic acinus of diabetic rats.   Methods  Twenty SD rats were randomly divided into normal control group (n=10) and streptozotocin (STZ)-induced diabetic group (n=10). At the end of 14 weeks inducement

all rats were sacrificed and venous blood and pancreatic tissues were collected. The levels of fasting blood glucose

insulin and blood fat were determined to identify the establishment of diabetic rat model. The specimens of pancreas were fixed and embedded. Hematoxylin-eosin staining was performed to observe the morphological changes. Periodic acid-Schiff (PAS) staining was carried out for the vascular changes. The expressions of type Ⅰ and Ⅳ collagen were determined by inmmunohistochemical method. BMK1/ERK5mRNA was detected by in situ hybridization.   Results  Compared with the control

in diabetic group the vascular wall was thickening

inflammatory cells were infiltrated in perivascular area

local acinus was atrophy and the expression of type Ⅳ collagen was mainly expressed in vascular basement membrane

while type Ⅰ collagen was in local atrophy acinus tissue with inflammation (P0.05). ERK5 mRNA was expressed in the vascular endothelial cells

and significantly increased in diabetic rats (P0.01). PAS-positive substances   were deposited in the vascular wall in diabetic group but were not observed in the control group.   Conclusion  ERK5 may contribute to the microcirculation disturbance in the pancreas of diabetic rats with dyslipidemia

moreover

ERK5 may be one reason for pathogenesis of acute pancreatitis due to hyperlipidemia.