急性胰腺炎肠道屏障损害机制的研究进展

Dynamic changes in the levels of serum interleukin-2 and interleukin-10 and the expression of Fas in the intestinal mucosa of rats with severe acute pancreatitis

AIM: To investigate the dynamic changes in the levels of serum interleukin (IL)-2 and IL-10 sFas and IL-2/IL-10 in rats with severe acute pancreatitis (SAP), and to explore the expression of Fas in the intestinal mucosa of rats with severe acute pancreatitis.

METHODS: A total of 64 Sprague-Dawley (SD) rats were randomly divided into normal control group and SAP group. A SAP model was induced by injection of 50 g/L sodium taurocholate under the pancreatic membrane. The normal control group received isovolumetric injection of 9 g/L physiological saline solution using the same method. Blood samples from the rats in each group were obtained via the superior mesenteric vein to measure the levels of IL-2, IL-10 and sFas, and to calculate the value of IL-2/IL-10. The levels of IL-2, IL-10 and sFas were determined by ELISA. The severity of pancreas and intestinal mucosal injury was evaluated by pathologic score. The expression of Fas in intestinal mucosal tissue was determined by immunohistochemistry.

RESULTS: The levels of serum IL-2 in the SAP group were significantly higher than those in the normal control group at 0.5 h after injury (3.53 ± 0.62 ng/L vs 2.79 ± 0.51 ng/L, 4.35 ± 1.11 ng/L vs 2.93 ± 0.89 ng/L, 6.94 ± 1.55 ng/L vs 4.81 ± 1.23 ng/L, 4.80 ± 1.10 ng/L vs 3.41 ± 0.72 ng/L, P < 0.01) and peaked at 6 h after injury. The levels of serum IL-10 in the SAP group were significantly higher than those in the normal control group at 6 h after injury (494.98 ± 11.23 ng/L vs 89.18 ± 32.52 ng/L, 93.28 ± 25.81 ng/L vs 77.15 ± 22.60 ng/L, P < 0.01). The IL-2/IL-10 ratio in the SAP group was significantly higher than that in the normal control group at 0.5 h and 2 h after injury, and significantly lower than that in the normal control group at 6 h after injury (P < 0.01), after which this ratio returned to the control level (P > 0.05). The pathological changes were significantly aggravated in the SAP group compared with the normal group. Immunohistochemistry staining showed. Fas from normal intestinal tissue. Fas expression in intestinal tissue gradually increased 0.5 h after the induction of pancreatitis, and its a peak at 12 h after induction.

CONCLUSION: Fas is involved in the pathogenesis of pancreatitis-associated intestinal injury. The mechanisms underlying this involvement of Fas may be related to Fas-mediated T helper cell apoptosis.

Effects of propofol on apoptosis of intestinal epithelial cells in rats with gut ischemia-reperfusion injury

AIM: To investigate the effects of propofol on apoptosis of intestinal epithelial cells in rats with gut ischemia-reperfusion (I/R) injury.

METHODS: Ninety-six Wistar rats were randomly divided into three groups: sham operation, control (I/R + saline) and propofol (I/R + propofol) groups. Propofol (0.1 mg/kg) was injected into the guts of rats in the I/R + propofol group immediately after the superiormesentericartery (SMA) was clipped. The rate of apoptosis of intestinal epithelial cells was determined using the TdT-mediated d-UTP-biotin nick end-labeling (TUNEL) method. The expression of Caspase-3 and bcl-2 proteins in intestinal epithelial cells was examined by immunohistochemistry. Pathological changes in gut epithelial cells were assessed by Chiu's scores. Measurements were taken at 0, 30, 60, 120 and 240 min after reperfusion.

RESULTS: The rate of apoptosis of intestinal epithelial cells (P < 0.01) and the levels of Caspase-3 protein were significantly lower in the I/R + propofol group than that in the control group at 0, 30, 60, 120 and 240 min after reperfusion (104.4 ± 5.3 vs 146.4 ± 7.6; 97.4 ± 6.2 vs 130.4 ± 7.4; 134.4 ± 5.1 vs 170.4 ± 8.1; 125.4 ± 6.2 vs 160.4 ± 9.5; and 101 ± 5.8 vs 120.4 ± 8.2, respectively, all P < 0.01), whereas the levels of bcl-2 protein increased dramatically (13.34 ± 4.12 vs 6.72 ± 2.59; 14.96 ± 4.85 vs 8.24 ± 3.13; 15.29 ± 5.28 vs 9.63 ± 2.89; 10.39 ± 3.61 vs 9.63 ± 2.89; 10.39 ± 3.61 vs 5.96 ± 1.93; 11.08 ± 4.83 vs 6.87 ± 2.43, respectively, all P < 0.01). Pathological injures were seen to have been alleviated.

CONCLUSION: Enteral administration of propofol reduces apoptosis of intestinal epithelial cells in rats with gut ischemia-reperfusion injury.

Protective effects of carbachol on intestinal epithelial cells against oxidative injury

AIM: To study the effects of carbachol on the H₂O₂-oxidative injury of intestinal epithelial cells (IEC).

METHODS: IEC were cultured with the presence of H₂O₂in vitro to induce the oxidative injury. IEC were divided into 3 groups: control group, H₂O₂ (2.5 mmol/L) group and carbachol (100 μmol/L) group. The viability of IEC was measured by MTT assay. The level of lactate dehydrogenase (LDH) in culture media and the malondialdehyde (MDA) content in IEC were measured.

RESULTS: In compared with those in control group, LDH level (7.40 ± 2.10 vs 0.81 ± 0.12, P < 0.01) and MDA content in H₂O₂ group were significantly elevated, and the viability of IEC was obviously decreased (37.25% ± 0.80% vs 100% ± 0.13%, P < 0.01). However, in carbachol group, LDH level (4.64 ± 1.31 vs 7.40 ± 2.10, P < 0.01) and MDA content were lower while IEC viability was obviously higher than those in H₂O₂ group (78.70% ± 2.80% vs 37.25% ± 0.80%, P < 0.01).

CONCLUSION: Carbachol can protect rat IEC from the oxidative injury.

Effects of reasonable pre-operative nutrition on recoveries of gastrointestinal cancer patients

AIM: To investigate the effects of pre-operative enteral and parenteral nutrition (EN-PN) on the malnourished gastrointestinal cancer patients.

METHODS: Sixty-nine malnutritional patients with gastrointestinal cancer were randomly divided into 3 groups: EN-PN group (n = 23), parenteral nutrition group (PN, n = 24) and non-nutrition group (NN, n = 22). EN-PN and PN group were received nutritional support of the same nitrogen and calorie 7 d before operation. Each group received the same nutritional support (EN-PN) 24 h after operation. The levels of serum albumin (ALB), pre-albumin (PA), transferrin (TFN), endotoxin (ET), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) were detected 7 d before and after operation. The levels of serum IgA, IgG and IgM, the activity of natural killer (NK) cells and the ratio of CD4 to CD8 (CD4/CD8) were measured to evaluate the immune function of the patients. The incidence rate of complications and mean hospitalized time were compared between the three groups.

RESULTS: After operation, the levels of serum PA (0.27 ± 0.06 g/L), TFN (2.81 ± 0.65 g/L) and IgG (10.43 ± 0.86 g/L), the activity of NK cells (18.04% ± 4.56%) and the value of CD4/CD8 (4.98 ± 1.21) were significantly higher in EN-PN group than those in PN (0.19 ± 0.04, 2.01 ± 0.32, 8.76 ± 0.65 g/L, 11.01% ± 3.01%, 2.11 ± 0.65, respectively, P < 0.05) and NN group (0.15 ± 0.03, 1.32 ± 0.27, 9.05 ± 0.79 g/L, 6.45% ± 2.23%, 1.22 ± 0.79, respectively, P < 0.05), but the levels of serum ET (4.23 ± 2.01 ng/L), IL-6 (40.22 ± 7.43 ng/L) and TNF-α (33.04 ± 4.56 ng/L) markedly lower than those in PN (8.23 ± 3.65, 55.21 ± 9.32, 47.22 ± 8.45 ng/L, respectively, P < 0.01) and NN group (10.66 ± 5.23, 67.01 ± 10.21, 56.43 ± 9.67 ng/L, respectively, P < 0.01). In comparison with those in PN and NN group, the incidence rate of complications (11.3% vs 16.4%, 21.6%) and mean hospitalized time (7.0 ± 1.4 d vs 11.0 ± 2.4, 13.0 ± 2.8 d) were also notably decreased (P < 0.01).

CONCLUSION: Pre-operative EN-PN is safe and effective in the malnutritional patients with gastrointestinal cancer, and it can accelerate the recoveries of post-operative patients.

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Changes of endotoximia, cytokines and nitric oxide and therapeutic effects of sandostatin in rats with severe acute pancreatitis

AIM: To study the roles of endotoximia, cytokines and nitric oxide in the development of severe acute pancreatitis (SAP) and the therapeutic effects of sandostatin (SS) in rats.

METHODS: SAP models were induced by retrograde injection of 15 g/L sodium deoxycholate and then treated by SS. The plasma levels of endotoxin (ET), lipid peroxide (LPO), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and nitric oxide (NO), as well as the expression LPO, TNF-α, IL-6 and NO in pancreatic tissues, were measured. The changes of pancreatic histology were examined under light microscope.

RESULTS: As Compared with those in sham operation group, the plasma levels of ET, LPO, TNF-α, IL-6 and NO were markedly higher in SAP group (P < 0.01), and the changes of ET, LPO, TNF-α and NO at 6 h were higher (898 ± 114 EU/L, 24.58 ± 1.23 μmol/L, 246.3 ± 16.5 ng/L, 162.8 ± 10.9 mmol/L, P < 0.05) than those at 12 and 24 h. The changes of LPO, TNF-α, IL-6 and NO in pancreatic tissues of SAP group were obviously higher in comparison with those of sham group (3.31 ± 0.85 μmol/g vs0.33 ± 0.04 μmol/g, P < 0.01; 2.57 ± 0.14 ng/g vs 0.16 ± 0.04 ng/g, P < 0.01; 85.6 ± 24.6 ng/g vs 32.5 ± 5.7 ng/g, P < 0.01; 15.3 ± 1.2 mmol/g vs 6.6 ± 1.4 mmol/g, P < 0.01); and severe damages of pancreatic tissues were observed under light microscope. In SAP group, the plasma levels of LPO, TNF-α, IL-6 and NO were significantly correlated with ET level (r = 0.858,P < 0.01; r = 0.958, P < 0.01; r = 0.918, P < 0.01; r = 0.875, P < 0.01). The indexes mentioned above in SS group were obviously ameliorated in comparison with those in SAP group (P < 0.01).

CONCLUSION: Endotoximia, cytokines and NO play important roles in the development of severe acute pancreatitis. Sandostatin can block the chain reaction caused by these factors.