Effect of defunctionalization on colon carcinogenesis in the rat.

Abstract

OBJECTIVE:

to examine the effect of fecal absence on experimental colon carcinogenesis in both male and female rats.

MATERIAL AND METHODS:

a total of 138 10-week-old Sprague-Dawley, male and female rats were divided into five groups: A) 20 rats, no treatment; B) 26 rats, colonic defunctionalization; C) 30 rats, 18 weekly doses of dimethylhydrazine (DMH), 21 mg/kg body weight each, from the beginning of the study; D) 20 rats, ethylen-diamine-tetraacetic acid for 18 weeks; and E) 42 rats, same surgical procedure as rats in group B plus DMH injections at the same doses as rats in group C. Animals were sacrificed after 25-27 weeks. Number of tumors, their location, and pathological findings were all compared between groups.

RESULTS:

no tumors developed in the dimethylhydrazine-free groups. No differences were obtained either in number of tumors or tumors per rat for group C as compared to group E. Fecal absence was associated with smaller-sized tumors (p = 0.007), greater numbers of non-mucinous tumors (p = 0.00009), better differentiation (p = 0.0054), and lesser penetration into the wall (p = 0.015) for group E as compared to group C. In the dimethylhydrazine group, fecal absence altered the number of tumors developing in males as compared to female rats (p = 0.025). Moreover, this fecal absence showed no inhibitory effect on right colonic tumors (p = 0.0065).

CONCLUSIONS:

fecal absence alters the DMH-carcinogenic pattern in the defunctionalized colon when using an experimental model in both male and female rats.

• Authors: S Pérez-Holanda, L Rodrigo, J Viñas-Salas, C Piñol-Felis, C Ildefonso
• Journal: Revista espanola de enfermedades digestivas (Rev Esp Enferm Dig) Vol. 98 Issue 9 Pg. 644-54 (Sep 2006) ISSN: 1130-0108 [Print] Spain
• PMID: 17092196 (Publication Type: Journal Article)

Chemical References

• Dimethylhydrazines

Topics

• Animals
• Colorectal Neoplasms (etiology, pathology)
• Dimethylhydrazines (administration & dosage)
• Feces
• Female
• Male
• Rats
• Rats, Sprague-Dawley