The aim of this research was to compare the efficiency of different murine lines for genotoxicity assays. Rats and mice of different murine lines were used. The spontaneous and induced indexes were evaluated according to alkaline comet assay of peripheral blood leukocytes, micronucleus and chromosomic aberration assay of bone marrow cell, and sperm head morphology assay. In most of the evaluated assays the line of Balb/c mice turned out to be the ideal biomodel, with less spontaneous indexes and high induced indexes to the mutagen used; allowing to detect in a narrow error margin those substances that are classified of very low genotoxicity. These results demonstrate that genetically the line of Balb/c mice in both sexes is more stable than the other ones evaluated. This suggests the use of the Balb/c line on in vivo genotoxicity assay will increase sensibility and robustness.

Objective: The seed oil extract of Carapa guianensis has various biomedical applications. Recently this extract was evaluated for expressing great potential as antioxidant on in vivo assays. Besides its safety has been evaluated in several genotoxicity assays, not being toxic in different models of DNA damage. The aim of this research was to evaluate the genotoxic potential of seed oil extract of C.guianensis on peripheral blood leukocytes of Sprague-Dawley rats using the comet assay. Methods: Five experimental groups were formed consisting of five male and five female Sprague-Dawley rats in each group. A placebo group (2% Tween 65), three dose levels of the extract (400, 1000 and 2000 mg/kg) administered orally for 14 days, and a positive control group treated with cyclophosphamide (CP) at a dose of 50 mg/kg intraperitoneally 48 and 24 h before euthanasia were established. After the experimental period the animals were anesthetized and a blood drop was extracted for performing the comet assay of peripheral blood leukocytes; then the rats were euthanized under ether atmosphere. Results: The results presented no differences between controls and extract-treated animals of both sexes in the percentage of nucleoids at different levels, arbitrary units and length of DNA migration. However, validating our result, the CP-treated animals showed significant DNA damage. Conclusion: The seeds oil extract of C.guianensis did not exert genotoxic effect as measured through the comet assay on peripheral blood leukocytes of male as well as female Sprague-Dawley rats. [J Exp Integr Med 2013; 3(3.000): 231-236

The discovery of new drugs with antigenotoxic effect constitutes in our days a prioritized line of research. In this work was evaluated the response of Sprague Dawley rats (both sexes) against cyclophosphamide and bleomycin by means of alkaline comet assay of peripheral blood leukocytes and micronuclei in bone marrow cells assay as antigenotoxicy biomodel. Higher induction of the strand breaks (SB) and alkali-labile sites formation on DNA damage were obtained with the use of the cyclophosphamide and bleomycin, both in the design of 48 and 24 hr administration before the euthanasia. In the mironucleis assay was obtained high results of induction the micronucleus formation in bone marrow cells with cyclophosphamide was administered 48 and 24 hr before euthanasia in both sexes. These results are useful in studies of drugs evaluation that they have not been explored in to the in vivo antigenotoxicity environment.

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The aim of this paper is to compare the spontaneous and induced with cyclophosphamide micronucleus indexes in bone marrow cells of the Sprague Dawley, Lewis and Wistar rat lines. Five experimental groups were formed (10 animals of each sex and of each line, in every group). The first group was used as the negative control (intact animals), the second one was exposed to oral administration of drugs; other conditions were the same as for the other groups. The third group was treated with 2 % Tween 65 and the fourth group was treated with 0.9 % NaCl. Both substances were administered by oral way to 2 ml/kg during 14 days. The fifth group was treated intraperitoneally with strong mutagen cyclophosphamide in the dose of 50 mg/kg (10 ml/kg in solution), on 48 th and 24 th hours before euthanasia. The Sprague Dawley line (both sexes) was significantly different from the other lines. Rats of this line had lower index of spontaneous formation of micronuclei, higher index of cyclophosphamide-induced micronucle formation, percent of micronucleated erythrocytes in bone marrow and the index of cytotoxicity. The results obtained make it possible to identify the most appropriate line of rats as model animals for studies of genotoxicity. It will allow also to obtain more accurate estimates of genotoxicity of various substances.