Preventive effect of gelatinizedly-modified chitosan film on peritoneal adhesion of different types

AIM To comparatively study the preventive effect of gelatinizedly-modified chitosan film on peritoneal adhesions induced by four different factors in rats. METHODS Chitosan was chemically modified by gelatinization, and made into films of 60 microm in thickness, and sterilized. Two hundred Sprague-Dawley rats were randomly divided into five groups, Sham-operation group (group A), wound-induced adhesion group (group B), purified talc-induced adhesion group (group C), vascular ligation-induced adhesion group (group D), and infection-induced adhesion group (group E), respectively. In each group, the rats were treated with different adhesion-inducing methods at the cecum of vermiform processes and then were divided into control and experimental subgroups. Serous membrane surface of vermiform processes were covered with the films in the experimental subgroups, and no films were used in the control subgroups. After 2 and 4 wk of treatments, the abdominal cavities were reopened and the adhesive severity was graded blindly according to Bhatia's method. The cecum of vermiform processes were resected for hydroxyproline (OHP) measurement and pathological examination. RESULTS Adhesion severity and OHP level: After 2 and 4 wk of the treatments, in the experimental subgroups, the adhesions were significantly lighter and the OHP levels were significantly lower than those of the control subgroups in group B (2 wk: 0.199 +/- 0.026 vs 0.285 +/- 0.041 microg/mg pr, P < 0.001; 4 wk: 0.183 +/- 0.034 vs 0.276 +/- 0.03 microg/mg pr, P < 0.001), D (2 wk: 0.216 +/- 0.036 vs 0.274 +/- 0.040 microg/mg pr, P = 0.004; 4 wk: 0.211 +/- 0.044 vs 0.281 +/- 0.047 microg/mg pr, P = 0.003) and E (2 wk: 0.259 +/- 0.039 vs 0.371 +/- 0.040 microg/mg pr, P < 0.001; 4 wk: 0.242 +/- 0.045 vs 0.355 +/- 0.029 microg/mg pr, P < 0.001), but there were no significant differences in groups A (2 wk: 0.141 +/- 0.028 vs 0.137 +/- 0.026 microg/mg pr, P = 0.737; 4 wk: 0.132 +/- 0.031 vs 0.150 +/- 0.035 microg/mg pr, P = 0.225) and C (2 wk: 0.395 +/- 0.044 vs 0.378 +/- 0.043 microg/mg pr, P = 0.387; 4 wk: 0.370 +/- 0.032 vs 0.367 +/- 0.041 microg/mg pr, P = 0.853); Pathological changes: In group B, the main pathological changes were fibroplasias in the treated serous membrane surface and in group D, the fibroplasia was shown in the whole layer of the vermiform processes. In group E, the main pathological changes were acute and chronic suppurative inflammatory reactions. These changes were lighter in the experimental subgroups than those in the control subgroups in the three groups. In group C, the main changes were foreign body giant cell and granuloma reactions and fibroplasias in different degrees, with no apparent differences between the experimental and control subgroups. CONCLUSION The gelatinizedly-modified chitosan film is effective on preventing peritoneal adhesions induced by wound, ischemia and infection, but the effect is not apparent in foreign body-induced adhesion.