RESUMEN
The objective of the present study was to investigate the biomechanical changes of the small intestinal wall occurring in fecal peritonitis associated with diclofenac sodium (DS). Wistar rats were divided at random into the following groups: Group 1 (DS), 60 animals that received an intramuscular injection of diclofenac sodium at the dose of 2 mg/kg body weight; Group 2 (Per), 60 animals that received an intraperitoneal injection of a suspension of human feces, with interruption of peritonitis after 6 hours; Group 3 (Per+DS), 60 animals that received an intraperitoneal injection of a suspension of human feces and DS according to the same scheme as used for Groups 1 and 2; Control Group, 12 animals injected intramusculary. The animals in Groups 1, 2 and 3 were successively sacrificed on the 2nd, 7th and 14th days after the interruption of peritonitis and/or the beginning of treatment, when breaking strength was determined and tissue hydroxyproline was measured. No deaths occured among DS animals, two deaths occurred in the Per group and six the Per+DS group between the 2nd and 12th postoperative day. The breaking strength of the DS group returned to normal levels on the 14th day of treatment, whereas in the Per and Per+DS groups the breaking strength continued to be below normal levels. On the basis of the experimental conditions and methods used, we conclude that diclofenac sodium and peritonitis decrease the breaking strenght and the tissue collagen of the small intestine. When peritonitis was associated with diclofenac sodium there was a summation of the deleterious effects observed separately in the Per and DS groups.