Genotoxicity of carbon tetrachloride and the protective role of essential oil of Salvia officinalis L. in mice using chromosomal aberration, micronuclei formation, and comet assay

The present work was conducted to evaluate the genotoxic effect of carbon tetrachloride (CCl₄) in mouse bone marrow and male germ cells. The safety and the modulating activity of sage (Salvia officinalis L.) essential oil (SEO) against the possible genotoxic effect of CCl₄ were also evaluated. A combination of in vivo mutagenic endpoints was included: micronucleus (MN), apoptosis using dual acridine orange/ethidium bromide (AO/EB) staining, comet assay, chromosomal aberrations (CAs), and sperm abnormalities. Histological examination of testis tissues was also studied. The extracted SEO was subjected to gas chromatography-mass spectrometry (GC-MS) for identifying its chemical constituents. Safety/genotoxicity of SEO was determined after two consecutive weeks (5 days/week) from oral treatment with different concentrations (0.1, 0.2, and 0.4 mL/kg). For assessing genotoxicity of CCl₄, both acute (once) and subacute i.p. treatment for 2 weeks (3 days/week) with the concentrations 1.2 mL/kg (for acute) and 0.8 mL/kg (for subacute) were performed. For evaluating the protective role of SEO, simultaneous treatment with SEO plus CCl₄ was examined. In sperm abnormalities, mice were treated with the subject materials for five successive days and the samples were collected after 35 days from the beginning of treatment. Based on GC-MS findings, 22 components were identified in the chromatogram of SEO. The results demonstrated that the three concentrations of SEO were safe and non-genotoxic in all the tested endpoints. Negative results were also observed in bone marrow after acute and subacute treatment with CCl₄. In contrast, CCl₄ induced testicular DNA damage as evidenced by a significant increase of CAs in primary spermatocytes, sperm abnormalities, and histological distortion of testis. A remarkable reduction in these cells was observed in groups treated with SEO plus CCl₄ especially with the two higher concentrations of SEO. In conclusion, SEO is safe and non-genotoxic under the tested conditions and can modulate genetic damage and histological alteration induced by CCl₄ in the testes.