ALDH2 deficiency in pancreatic acinar cells aggravates acute pancreatitis by promoting NLRP3 inflammasome activation through autophagy

Figure 2 Acute pancreatitis induction promoted aldehyde dehydrogenase 2 enhancement with reduced enzymatic activity, nod-like receptor family pyrin domain-containing 3 inflammasome activation, and autophagic substrate accumulation in porcine models. Porcine acute pancreatitis (AP) was induced by endoscopic cannulation of the pancreatic duct followed by injection of contrast material (10 mL, Omnipaque). Pancreatic tissues were harvested at 24 hours after model induction. A: Representative hematoxylin and eosin staining images of porcine pancreas and corresponding pathological scores in the AP and control groups (n = 3 per group). Orange arrows denote inflammatory cells. Black arrows indicate vacuolization. Scale bar: 50 μm, magnification, 20 μm; B and C: Serum amylase, lipase, interleukin (IL)-1β, IL-6 and IL-18 levels before modeling and 24 hours after modeling in the porcine AP group (n = 3); D: Aldehyde dehydrogenase 2 (ALDH2) enzyme activity (biochemical assay) and protein expression (immunoblotting) in pancreatic tissues of AP group and control group (n = 3 per group); E: Immunofluorescence analysis of ALDH2 in pancreatic tissues of AP group and control group (n = 3 per group). Scale bar: 20 μm; F: The expression of nod-like receptor family pyrin domain-containing 3 (NLRP3), apoptosis associated speck-like protein (ASC) and caspase-1 for AP group and control group in porcine pancreatic tissues by immunoblotting (n = 3 per group); G: Immunofluorescence analysis of NLRP3 (red) - ASC (green) and NLRP3 (red) - caspase-1 (green) in pancreatic tissues of AP group and control group. Scale bar: 20 μm, magnification, 10 μm; H: The expression of P62 and microtubule-associated protein light chain 3B (LC3B) for AP group and control group in porcine pancreatic tissues by immunoblotting (n = 3 per group); I and J: Immunofluorescence analysis of P62 and LC3B in pancreatic tissues of AP group and control group (n = 3 per group). Scale bar: 20 μm; K: Representative transmission electron microscopy images and quantitative analysis in pancreatic tissue of AP group and control group. Arrows denote autophagic vesicles. Scale bar: 5 μm. ^aP < 0.05, ^bP < 0.01, ^cP < 0.001. AMY: Amylase; LPS: Lipase; LC3B: Light chain 3B; ALDH2: Aldehyde dehydrogenase 2; AP: Acute pancreatitis; IL: Interleukin; NLRP3: Nod-like receptor family pyrin domain-containing 3; ASC: Associated speck-like protein.