Spatial and temporal differences of HMGB1 expression in the pancreas of rats with acute pancreatitis.

We aimed to investigate the spatial and temporal differences in expression between HMGB1 and early-stage inflammatory cytokines (IL-1, IL-6 and TNF-α) in pancreas tissue in rats with acute pancreatitis. SD rats (BW 350 ± 30 g, n = 48) were randomly divided into the experimental group (n = 36) which were injected with 5% sodium taurocholate into the bilipancreatic duct retrogradely to produce acute necrotic pancreatitis (ANP) rat models, and the sham-operated (SO) group (n = 12) injected with equal dose of saline. The rats were sacrificed at different time points at 0 h, 3 h, 6 h, 12 h, and 24 h post modeling, respectively. The peripheral blood amylase and different inflammatory factors in ANP rats at different time points were detected by ELISA, and the expression of HMGB1 in the pancreatic tissue was detected by immunohistochemistry, Western blot and Q-PCR methods. Results showed that the serum amylase in the ANP model rats was significantly higher than the sham-operated group (P < 0.05). The early inflammatory factors (IL-1, TNF-α and IL-6) increased quickly at 3 h after the model induction, reached the peak level at 6 h (higher than SO group, P < 0.05), then decreased at 12 h, and at 24 h the levels were lower than those at 12 h (P < 0.05). The HMGB1 level in the pancreatitis tissue did not change significantly at 3 h and 6 h (P > 0.05), however, it increased remarkably at 12 h, and maintained up to 24 h (P > 0.05). As a late inflammatory factor, the expression of HMGB1 in acute pancreatitis was obviously later than the early inflammatory factors IL-1, TNF-α and IL-6. HMGB1 may play a key role in maintaining the development of the acute pancreatitis.