Hyaluronidase treatment of graft pancreatitis in rats: marked effects on the blood perfusion of the transplanted pancreas.

Hyaluronan is known to accumulate in tissues during inflammatory diseases associated with graft implantation and rejection of organ allografts. The aim was to evaluate whether hyaluronidase treatment affected hyaluronan content and blood perfusion in graft pancreatitis. Syngeneic rat pancreatic-duodenal transplantations were performed. Two days later blood flow measurements were made with a microsphere technique in both grafted and endogenous pancreas in animals treated with daily injections of vehicle or hyaluronidase (20.000 U/kg). Non-transplanted rats served as controls. Also, samples for analysis of hyaluronan and water content were taken. The hyaluronan content of the pancreatic graft was increased after transplantation. Hyaluronidase treatment markedly reduced total pancreatic and islet blood flow in both grafted and endogenous pancreas, whereas duodenum blood flow was unaffected. No blood flow effects were seen in non-transplanted control rats. Hyaluronan content was increased in the grafted pancreas, but hyaluronidase treatment decreased it to levels comparable to those of the endogenous gland. There were no differences in hyaluronan content in the endogenous pancreases of transplanted and non-transplanted rats. Graft pancreatitis after rat pancreas transplantation is associated with an increased hyaluronan content, which can be reduced by treatment with hyaluronidase. Hyaluronidase treatment of the graft recipients effected a 50% reduction in total pancreatic and islet blood flow in the graft, as well as in the endogenous pancreas. The functional importance of this is at present unknown.