Protective effect of ascorbic acid in experimental gastric cancer: reduction of oxidative stress.
OBJECTIVE
Oxidative stress participates in the cell carcinogenesis by inducing DNA mutations. Our aim was to assess whether ascorbic acid, an antioxidant, could have a role in preventing ROS (Reactive Oxygen Species) generation in experimental gastric carcinoma in a rat model.


METHODS
Experimental gastric cancer was induced in twelve Wistar male rats (weighting 250-350 g) by profound duodeno-gastric reflux throught split gastrojenunostomy. The rats were allocated to the following groups: Group I (n=6) was the control; Group II (n=6) which was mantained with daily intake of tape water with Vitamin C (30 mg/Kg). After 6 or 12 months, samples of gastric tumor or non tumor mucosa were taken from the anastomosis of both groups. Oxidative stress was measured by superoxide quantification through lucigenin-amplified chemiluminescence base and by staining with Nitrobluetetrazolium. The histopathologic confirmation of adenocarcinoma was made by eosin-hemathoxilin method.


RESULTS
The intestinal type of gastric adenocarcinoma was microscopically identified in all animals of group I whereas only 3 rats of group II showed an adenocarcinoma without macroscopic evidence of them. The cancers were located in the anastomosis in all cases. Basal luminescence from tumor gastric tissue generated 38.4+/-6.8 count per minute/mg/X10(6) (mean+/-SD) and 14.9+/-4.0 count per minute/mg/X10(6), respectively, in group I and II animals (P<0.05). The Nitrobluetetrazolium method showed intense staining in tumor tissues but not in non neoplasic mucosa.


CONCLUSIONS
Experimental gastric tumors seem to produce more reactive oxygen species than non neoplasic gastric tissue. The reduction of oxidative stress and gastric tumor incidence in rats were induced by the intake of ascorbic acid. Therefore, it may have a role in the prevention of gastric carcinoma.
Oliveira
Claudia P M S
CP
Department of Gastroenterology School of Medicine, University of Sao Paulo, Av Dr Eneas de Carvalho Aguiar no 255, Instituto Central 9th Floor, 9159, 05403000 Sao Paulo, Brazil. mauclaud@uol.com.br
Kassab
Paulo
P
Lopasso
Fabio P
FP
Souza
Heraldo P
HP
Janiszewski
Mariano
M
Laurindo
Francisco R M
FR
Iriya
Kioshi
K
Laudanna
Antonio A
AA
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology*; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000517:prevention & control*
D000975:Antioxidants; D001205:Ascorbic Acid