The jejunoileal bypass provokes morphological changes in the large intestine? An experimental study in rats.
OBJECTIVE
To analyse histopathological alterations characterized by the mitotic index in the mucosa of the large intestine in Wistar rats submitted to jejunoileal bypass operation after continued administration of sodium nitrite and vitamin C to different groups.


METHODS
Eighty male Wistar rats were employed and separated into 12 groups. In the control group (20 rats): five animals ingested only water; five animals received vitamin C; five animals received sodium nitrite and five received sodium nitrite + vitamin C. In the sham group (20 rats), the animals were anesthetized and underwent midline laparotomy and only intestinal manipulation was performed: five animals ingested only water; five animals received vitamin C; five animals received sodium nitrite and five received sodium nitrite + vitamin C. In the operated group 40 rats underwent a jejunoileal bypass surgery: ten animals ingested only water; ten animals received vitamin C; ten animals received sodium nitrite and ten received sodium nitrite + vitamin C. The mean weight of the animals was measured weekly. The large intestine was subdivided into cecum (S1), ascending colon (S(2)), transverse colon (S(3)), descending colon (S(4)) and rectum (S(5)) for histopathological analysis and mitotic counts. The statistical analysis was used to compare the mitotic indices. The level of significance was 5%.


RESULTS
The mean of all the segments indicates that the sodium nitrite+vitamin C group obtained the lowest mitotic index compared to the other treatments in the control group. The segments S(1) and S(2) showed a statistical difference with the vitamin C treatment: a higher mitotic index and better preservation of the mucosa in the operated group. In the sham group the main statistical difference occurred only in the sodium nitrite+vitamin C group between the means of the segments.


CONCLUSIONS
The comparison of all the colonic segments of the various groups revealed a lower mitotic index in the animals treated with sodium nitrite+vitamin C. In addition, it was found that vitamin C did not present a statistically significant inhibiting effect on the preservation of the mucosa and the mitotic index.
Anatomy Department, Faculty of Veterinary Medicine, UNIFENAS, Alfenas-MG, Brazil.
Maria Cristina Costa
MC
Resck
Norair Salviano dos
NS
Reis
Denismar Alves
DA
Nogueira
Marina Rachel
MR
Araujo
Luiz Roberto
LR
Lopes
Nelson Adami
NA
Andreollo
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology*; D005520:Food Preservatives / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000187:drug effects / Q000473:pathology; D007420:Intestine, Large / Q000187:drug effects / Q000473:pathology*; D007581:Jejunoileal Bypass / Q000009:adverse effects*; D008297:Male; D008938:Mitosis / Q000187:drug effects* / Q000502:physiology; D008940:Mitotic Index; D051381:Rats; D017208:Rats, Wistar; D012977:Sodium Nitrite / Q000494:pharmacology*
D000975:Antioxidants; D005520:Food Preservatives; D012977:Sodium Nitrite; D001205:Ascorbic Acid