Influence of haemoxygenase 1 (HO-1) gene expression on intestinal mucosa injury induced by intra-abdominal hypertension in rats / 中华烧伤杂志

<p><b>OBJECTIVE</b>To observe the effects of up- or down-regulation of haemoxygenase 1 (HO-1) gene expression on intestinal mucosa injury induced by intra-abdominal hypertension (IAH).</p><p><b>METHODS</b>(1) Reproduction of rat model of up- or down-regulation of HO-1 gene expression. Twenty-four healthy adult Wistar rats were divided into Co-PP (HO-1 specific revulsive) 2.5 mg, Co-PP 5.0 mg, Sn-PP (HO-1 specific inhibitor) 2.5 mg, and control groups according to the random number table, with six rats in each group. Rats in groups Co-PP 2.5 mg and Sn-PP 2.5 mg were respectively given Co-PP 2.5 mg/kg and Sn-PP 2.5 mg/kg by intraperitoneal injection, once every 12 hours for 3 days. The rats in group Co-PP 5.0 mg were intraperitoneally injected with Co-PP 5.0 mg/kg, once a day for 3 days. The rats in control group were treated with equal volume of normal saline by intraperitoneal injection. All rats were sacrificed on post injection day (PID) 4, and intestinal mucosa tissues were collected for determination of HO-1 mRNA expression. Optimal dose of Co-PP was chosen for the following experiment. (2) The influence of up- or down-regulation of HO-1 gene expression on intestinal mucosa injury under IAH condition. Another 24 healthy adult Wistar rats were divided into control, IAH, Co-PP+IAH, and Sn-PP+IAH groups according to the random number table, with six rats in each group. The rats in groups Co-PP+IAH and Sn-PP+IAH were intraperitoneally injected with 2.5 mg/kg Co-PP and 2.5 mg/kg Sn-PP, once every 12 hours for 3 days. Equal volume of normal saline was intraperitoneally injected into the rats in control group, once every 12 hours for 3 days. Then, nitrogen gas pneumoperitoneum was used to establish the model of IAH in rats of the latter three groups on PID 4, with IAP at 20 mm Hg (1 mm Hg = 0.133 kPa) , and it was maintained for 2 hours. Puncture and intubation were performed in rats of control group without inflating nitrogen gas. Jejunal segment in the length of 10-15 cm was harvested for collecting intestinal mucosa tissues to determine the HO-1 mRNA expression and diamine oxidase (DAO) content. Serum obtained from portal vein blood was collected to determine the D-lactate, TNF-α, and IL-6 contents. Another jejunal segment in the length of 1-2 cm was harvested for histopathological examination. Data were processed with one-way analysis of variance and t test.</p><p><b>RESULTS</b>(1) The HO-1 mRNA expression in group Co-PP 2.5 mg was significantly higher than that in control and Co-PP 5.0 mg groups (with t values respectively 4.756, 3.175, P < 0.05 or P < 0.01). The HO-1 mRNA expression in group Sn-PP 2.5 mg was significantly lower than that in control group (t = 4.880, P < 0.01). The optimal dose of Co-PP for the following experiment was 2.5 mg/kg. (2) HO-1 mRNA expression in group Co-PP+IAH was 60 ± 5, and it was obviously higher than that of group IAH (49 ± 5, t = 3.811, P < 0.01) and control group (39 ± 4, t = 8.034, P < .001) . HO-1 mRNA expression was higher in group IAH than in control group (t = 3.826, P < 0.01). HO-1 mRNA expression in group Sn-PP+IAH was 29 ± 4, which was obviously lower than that of control group (t = 4.330, P < 0.01). The contents of DAO and D-lactate in group Co-PP+IAH were (0.52 ± 0.05) U/mL and (1.9 ± 0.6) mg/L, which were significantly lower than those in group IAH [(0.88 ± 0.06) U/mL and (4.3 ± 0.7) mg/L, with t values respectively 11.291, 6.376, P values all below 0.01], but still higher than those in control group [(0.34 ± 0.04) U/mL, (1.2 ± 0.5) mg/L, with t values respectively 6.886, 2.295, P < 0.05 or P < 0.01]. The contents of TNF-α and IL-6 were much lower in group Co-PP+IAH than in group IAH, but still higher than in control group (with t values from 3.781 to 18.557, P values all below 0.01). The contents of DAO, D-lactate, TNF-α, and IL-6 in group Sn-PP+IAH were all higher than those in the other 3 groups (with t values from 4.181 to 32.938, P values all below 0.01). Structure of epithelial cells from intestinal mucosa was intact and regularly arranged in rats of control group. Intestinal mucosal tissue was edematous, and the top of villi was anabrotic and necrotic in rats of group IAH. Compared with that of group IAH, the degree of intestinal mucosa injury was alleviated in rats of group Co-PP+IAH, while the pathology was aggravated in rats of group Sn-PP+IAH.</p><p><b>CONCLUSIONS</b>Up-regulation of HO-1 gene expression can ameliorate intestinal mucosa injury caused by IAH, thus protecting intestinal mucosa tissues.</p>

Effect of intra-abdominal pressure on respiratory system, circulatory system and renal function in rats and study on the method of determination of intra-abdominal pressure / 中华烧伤杂志

<p><b>UNLABELLED</b>OBJECTIVE To study the effects of intra-abdominal pressure (IAP) on respiratory system, circulatory system and renal function in rats. To investigate the difference between the direct measure and indirect measure methods (via inferior vena cava and bladder) for IAP.</p><p><b>METHODS</b>Sixty Sprague-Drawly (SD) rats were randomly divided into 5 groups with different IAP (IAP value of 1-5 groups was 5, 10, 15, 20, 25 mm Hg,respectively) and healthy control group, 10 rats in each group. The parameters of respiratory system, circulatory system, renal function, and IAP value were recorded. The correlation between direct and indirect measurement methods was also analyzed.</p><p><b>RESULTS</b>There were no significant differences in above parameters between IAPI and healthy control groups. Compared with those in healthy control group, PaO2 significantly decreased (P < 0.05), SCr and BUN increased significantly in IAP2 group (P < 0.05). Other indexes in IAP3, IAP4 groups increased (P < 0.05 or P < 0.01) except for respiratory frequency(RF) and MAP (P > 0.05). PaO2 and MAP decreased (P < 0.01), and other indexes increased (P < 0.05 or P < 0.01) in IAP5 group. The values obtained from the indirect measure method were positively correlated with that from the direct measure method (r = 0.937, 0.955, P < 0.01, respectively).</p><p><b>CONCLUSIONS</b>IAP can affect respiratory system, circulatory system and renal function in different degrees in rats. The indirect measure method can replace the direct measure method for IAP measure with little injuries.</p>

Influence of intra-abdominal hypertension on the intestinal permeability and endotoxin/bacteria translocation in rabbits / 中华烧伤杂志

<p><b>OBJECTIVE</b>To observe different degrees of intra-abdominal pressure and different duration on the intestinal permeability and endotoxin/bacteria translocation in rabbit model, so as to explore the mechanism of the development of abdominal compartment syndrome (ACS) and MODS.</p><p><b>METHODS</b>Rabbit model of intra-abdominal hypertension was established by injection of gaseous nitrogen into the peritoneal cavity. Thirty-nine New Zealand white rabbits were employed in the study. The change in intestinal permeability was determined by fluorescein isothiocyanate dextran (FITC-D) and two kinds of molecular probes of type II horseradish peroxidase (HRP-II). The effects of intra-abdominal hypertension on the endotoxin/bacteria translocation were also detected.</p><p><b>RESULTS</b>The contents of FITC-D and HRP-II in portal veins increased evidently (P < 0.01) when intra-abdominal pressure (IAP) was higher than 20 mmHg. The endotoxin (ET) content in portal vein in rabbits with IAP of 10 mmHg for 1, 2 and 4 hours exhibited no difference compared with that in normal control, while the ET content increased obviously after 1 hour with IAP of 20 mmHg and increased thereafter along with the prolongation of IAP, and increase in pressure. The bacterial translocation rates were 33.3%, 66.7% and 100% when IAP was maintained at 20 mmHg for 1, 2 and 4 hours, respectively, and there was evidence of bacterial translocation to the liver. The rate of bacterial translocation to intestinal mesenteric lymph nodes was 100% when IAP was 30 mmHg for 1 and 2 hours. There was no bacterial translocation to the spleen in all experimental rabbits.</p><p><b>CONCLUSION</b>Intestinal mucosal permeability increased significantly with increased endotoxin content in portal vein when IAP was higher than 20 mmHg. At the sane time, the bacteria could be translocate to intestinal mesenteric lymph nodes and liver, which might be constitute one of the important factors leading to the development of ACS and MODS.</p>