[The effect of carotenoids on rat stomach carcinogenesis, induced by N-methyl-N'-nitro-N-nitrosoguanidine]. / Deistvie karotinoidov na kantserogenexz zheludka u krys, indutsirovannykh N-metil-N'-nitro-N-nitrozoguanidinom.

The effect of natural carotenoids on gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitroguanidine (MNNG) was studied in 4 groups containing 105 rats. Highly carotenoid complex from wild rose fruits was added to drinking water of Group 1 (30 rats) at a dose of 15 mg/kg (as calculated per beta-carotene) 3 times weekly; as well as MNNG was present in water (0.01%). The carotenoid complex was supplemented to the ration 2 months before MNNG treatment and was continued within 15 months; MNNG treatment occurred within 6 months. Group 2 (30 rats) and Group 3 (30 rats) were treated with MNNG and the carotinoid complex, respectively; the 4 group (15 rats) was used as an intact control. Tumors were detected in 16 rats of 28 animals studied in Group 1 (57.1%) and in 11 rats of 25 animals in Group 2 (44%) (P < 0.05); malignization was found in the stomach and small intestine. The rate of involvement with gastric tumor in Group 1 was 3-fold higher as compared with those in the only MNNG treated animals--50% and 16%, respectively (P < 0.01). Tumors of the small intestine were detected in 5 rats of Group 1 (17.8%) and in 9 rats of Group 2 (36.6%); differences were statistically insignificant. However, carcinogenesis tended to accelerate. The mean time of stomach and small intestine tumor detection in Group 1 was equal to 286 and 276 +/- 46 days, respectively, and in Group 2--339.7 +/- 25.4 and 350.7 +/- 25.4 days, respectively (differences are insignificant.(ABSTRACT TRUNCATED AT 250 WORDS)

[The modified effect of carotenoids on rat forestomach carcinogenesis, induced by N-methyl-N'-nitro-N-nitrosoguanidine]. / Modifitsiruiushchii éffekt karotinoidov na kantserogenez predzheludka u krys, indutsirovannykh N-metil-N'-nitro-N-nitrozoguanidinom.

A modifying effect of carotenoids on carcinogenesis induced by N-methyl-H'-nitro-N-nitrosoguanidine (MNNG) in the rumen was studied in four groups of rats weighing 100-120 g. A diet of the first group contained a highly carotenoid complex from wild rose fruits at a dose of 30 mg/kg 3 times weekly; MNNG was administered at a dose of 5 mg per animal by means of a gastric tube for two days. Administration of the drug was repeated within 5 days. Treatment with the carotenoid complex was carried out 2 months before the MNNG administration. Group 2 and 3 received only MNNG or the carotenoid complex, respectively; Group 4 served as intact control. Tumors were detected in 33 rats of 81 animals studied (40.7%) in Group 1 and in 53 rats of 74 animals (71.6%) of Group 2 (P < 0.01). The mean time of the tumors detection constituted 40.7 +/- 9.5 days in Group I and 68.7 +/- 0.3 days (P < 0.05) in Group 2. All the tumors detected were localized in the rumen and consisted of papillomas appeared mainly as multiple forms. The data obtained suggest that carotenoids exhibited the modifying effect on MNNG-induced carcinogenesis of the rat rumen.