Table 1.
Scoring criteria for histologic damage in colon sections.
Figure 1.
Effects of different grades of nitrogen pneumoperitoneum on heart rate (HR) and noninvasive hemodynamic parameters.
A: HR; 90-min exposure to intra-abdominal hypertension caused a significant reduction in HR. Compared with the 0-mmHg group, the HR in the 12-, 16-, and 20-mmHg groups were significantly lower. B: Noninvasive hemodynamic parameters; the 90-min exposure to intra-abdominal pressures (IAPs) ≥8 mmHg caused significant reductions in the systolic blood pressure (SBP) and abdominal perfusion pressure (APP). The SBP and APP in the 8-, 12-, 16-, and 20-mmHg groups were significantly lower than those in the 0-mmHg group. As the IAPs increased, the noninvasive hemodynamic parameters deteriorated. All data are shown as means ± SD *P<0.05, **P<0.01, vs. 0 mmHg; ▴P<0.05, ▴▴P<0.01, vs. 4 mmHg; ★P<0.05, ★★P<0.01, vs. 8 mmHg; ▪P<0.05, ▪▪P<0.01, vs. 12 mmHg.
Table 2.
Effects of the different grades of nitrogen pneumoperitoneum on arterial blood gas parameters.
Figure 2.
The effects of the different grades of nitrogen pneumoperitoneum on colonic pro-oxidant-antioxidant balance.
A: Malondialdehyde (MDA), the product of lipid peroxidation. B–D: The antioxidant enzymes of glutathione peroxidase (GSH-Px), catalase (CAT), and superoxide dismutase (SOD). At 4 mmHg, the pro-oxidant-antioxidant balance was stable, and no significant differences in related parameters were detected between the 0- and 4-mmHg groups. Intra-abdominal pressures of ≥8 mmHg showed adverse effects on colonic pro-oxidant-antioxidant balance. Compared with that in the 0-mmHg group, the MDA concentrations in the 8, 12, 16, and 20-mmHg groups were significantly higher, whereas the CAT and GSH-Px concentrations tended to decline. No obvious changes in the SOD levels were detected. All data are shown as means ± SD. *P<0.05, **P<0.01, vs. 0 mmHg; ▴P<0.05, ▴▴P<0.01, vs. 4 mmHg; ★P<0.05, ★★P<0.01, vs. 8 mmHg. ▪P<0.05, ▪▪P<0.01, vs. 12 mmHg, ⧫P<0.05, vs. 16 mmHg.
Figure 3.
The effects of different grades of nitrogen pneumoperitoneum on intestinal permeability to FD-4.
Intra-abdominal hypertension significantly stimulated the intestinal permeability to FD-4.Compared with that in the 0-mmHg group, the FD-4 concentration in the 12-, 16-, and 20-mmHg groups were increased 5.2-,12.4- and 26.7-fold, respectively. Slightly elevated intra-abdominal pressures of 4 and 8 mmHg did not affect the FD-4 concentrations. No significant differences were observed between the 0-mmHg group and the 4- and 8-mmHg groups. All data are shown as means ± SD. **P<0.01, vs. 0 mmHg; ▴▴P<0.01, vs. 4 mmHg; ★★P<0.01, vs. 8 mmHg; ▪P<0.05, vs. 12 mmHg; ⧫P<0.05, vs. 16 mmHg.
Figure 4.
The effects of the different grades of nitrogen pneumoperitoneum on intestinal histologic damage.
A–F (0–20 mmHg, ×100): Morphological changes under the different grades of nitrogen pneumoperitoneum. The parts in the black box are magnified and listed from A1 to F1 (0–20 mmHg, ×200). As the intra-abdominal pressure (IAP) increased, the severity of the histologic changes increased. At 8 mmHg, nitrogen pneumoperitoneum induced slight inflammatory cell infiltration. When the IAP reached 20 mmHg, almost no intact intestinal mucosa was observed. G: Histological scores in the different groups. Compared with the 0-mmHg group, the 8-, 12-, 16-, and 20-mmHg groups had significantly higher histological scores. All data are shown as means ± SD. **P<0.01, vs. 0 mmHg; ▴▴P<0.01, vs. 4 mmHg; ★P<0.05, ★★P<0.01, vs. 8 mmHg; ▪P<0.05, ▪▪P<0.01, vs. 12 mmHg.
Figure 5.
The effects of different grades of nitrogen pneumoperitoneum on the expression levels of TJ proteins.
i: Immunohistochemical localization of claudin 5 and occludin (×200). Increased intra-abdominal pressures tended to reduce the expression levels of claudin 5 and occludin. A–D: Claudin 5. The black arrow indicates the positive signals for claudin 5 in the lateral membrane of the epithelia. E–H: Occludin. The white arrows indicate the positive signals for occludin in the apical cell borders of the colonic epithelia. ii: Western blotting results for claudin 5 and occludin. The expression levels of the proteins were normalized relative to actin. Compared with the 0-mmHg group, the 8-, 12-, 16-, and 20-mmHg groups had significantly reduced densities of claudin 5 and occludin. All data are shown as means ± SD. *P<0.05, **P<0.01, vs. 0 mmHg; ▴P<0.05, ▴▴P<0.01, vs. 4 mmHg;★★P<0.01, vs. 8 mmHg; ▪P<0.05, ▪▪P<0.01, vs. 12 mmHg.
Table 3.
Literature overview of the currently published animal experiments related to the present study.