Depth of invasion of oral squamous cell carcinoma in Nos2-knockout mice correlated to alterations in systemic inflammatory markers following 4NQO treatment

BACKGROUND

Peripheral blood analysis is a non-invasive and low-cost technique of prognostic value for several diseases, including oral cancer. Considering the role of inducible nitric oxide synthase in tumor-associated inflammation, this study purposed to evaluate the influence of this enzyme on peripheral blood parameters and systemic inflammatory biomarkers during murine oral carcinogenesis.

METHODS

A 50 μg/mL solution of 4-nitroquinoleine-N-oxide was provided to 15 C57BL/6J (Nos2+/+ ) and 16 B6.129P2-Nos2tm1Lau /J (Nos2-/- ) for 16 weeks. Animals were followed for 8 weeks after treatment. Blood samples and tongues were collected for hematological and histopathological analyses. Red blood cells, white blood cells, and platelet cell parameters were analyzed. The neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and the systemic immune-inflammation index were also calculated. The depth of invasion of all carcinomas was measured.

RESULTS

Differences were found in several blood parameters. The depth of invasion in Nos2-/- was lower than in Nos2+/+ (p = 0.009), and strong correlations were found between depth of invasion and neutrophil count (ρ = -0.68, p = 0.017), lymphocyte count (ρ = 0.72, p = 0.011), neutrophil-to-lymphocyte ratio (ρ = -0.65, p = 0.025), platelet-to-lymphocyte ratio (ρ = -0.73, p = 0.013), and systemic immune-inflammation index (ρ = -0.67, p = 0.037) in Nos2-/- mice.

CONCLUSION

Inducible nitric oxide synthase seems to have an important role in OSCC invasion and progression, which might be associated to alterations in immune-inflammatory cell dynamics evidenced by peripheral blood and systemic inflammatory biomarkers.

In vitro evaluation of the antibacterial and cytotoxic activities of the Euclea natalensis crude extract and fractions against oral infection agents

OBJECTIVE

This study aimed (i) to evaluate the antibacterial and cytotoxic activities of the crude extract and fractions obtained from Euclea natalensis A.D.C. roots against bacteria that cause periodontal disease and caries and (ii) to identify the isolated compounds.

DESIGN

The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the extract and fractions were determined by the microplate dilution assay. The cytotoxicity of the extract and fractions was evaluated by using the XTT colorimetric assay and normal human fibroblast cells (GM07492A, lung fibroblasts). The compounds present in the most promising fraction were determined by qualitative analysis through liquid chromatography coupled to mass spectrometry (HPLC-MS-ESI).

RESULTS

The MIC results ranged from 25 to > 400 μg/mL for the extract and from 1.56 to > 400 μg/mL for the fractions. To evaluate cytotoxicity, the tested concentrations of the extract and fractions ranged from 19.5 to 2500 μg/mL; IC₅₀ values between 625 and 1250 μg/mL were obtained. Analysis of the main bioactive fraction by HPLC-MS-ESI identified phenolic acids, coumarins, naphthoquinones, lignans, and fatty acids.

CONCLUSIONS

The E. natalensis root extract and fractions displayed good antibacterial activity against periodontal pathogenic and cariogenic bacteria. The antibacterial activity may be due to compounds present in the extract and fractions, which also showed low cytotoxicity to normal human cells. These data are relevant and encourage further research into this plant species, which may contribute to the discovery of new herbal medicines that will help to mitigate the problems caused by oral pathogenic bacteria.