ObjectiveTo explore the effect of the serum high mobility group box-1 (HMGB1) on oncosis of pancreatic acinar cells in the rat with severe acute pancreatitis (SAP). MethodsThirty-two healthy SD rats were randomly divided into 2 groups:sham operation group (SO group, n=8) and SAP group (n=24). Rats of SO group were only flipped the intestinal canal after laparotomy, but rats of SAP group were induced by retrograde injection of 3% sodium taurocholate into bilio-pancreatic duct in addition. Rats of SO group were sacrificed at 6 hours after operation, and rats of SAP group were sacrificed at 6 (SAP-6 hour group, n=8), 12 (SAP-12 hour group, n=8), and 24 hours (SAP-24 hour group, n=8) after operation respectively. Pancreatic tissues were stained by HE to observe pathological changes. Serum HMGB1 was measured by ELISA, and the oncosis percentage of pancreatic acinar cells was examined by flowcytometry. ResultsPathological results showed that structural integrity was observed in pancreatic acinar, and occasionally a single inflammatory cell infiltration was observed in rats of SO group. Swelling, interstitial edema, and inflammatory cell infiltration were observed in rats of SAP-6 hour group. Some necrosis of pancreatic acinar cell, stromal vascular congestion, and focal necrosis were observed in rats of SAP-12 hour group and SAP-24 hour group, which the pathological damage were worse over time. Levels of serum HMGB1 and oncosis percentages of pancreatic acinar cells in rats of 3 SAP subgroups were all higher than those of SO group (P < 0.01), and the 2 kinds of indexes both increased over time (P < 0.05). There was positive correlation between concentration of serum HMGB1 and oncosis percentages of pancreatic acinar cells in SAP rat during 24 hours after operation (r=0.846, P < 0.01). ConclusionsHMGB1 seems to play an important role in SAP by inducing oncosis of pancreatic acinar cells when inducing inflammatory reaction in rat with SAP.