A Comparative Study on Genotoxic and Oxidative DNA Damage in Oral Epithelial Cells of COVID-19 Suspected Patients

TL;DR

This study found that SARS-CoV-2 causes DNA damage and increases oxidative stress in oral cells of infected individuals.

Contribution

The study provides new evidence of SARS-CoV-2-induced genotoxicity and oxidative DNA damage in buccal epithelial cells.

Findings

Micronuclei counts and 8-OHdG levels were significantly higher in RT-PCR positive patients.

Inflammatory cell counts were elevated in the oral smears of infected individuals.

The epithelial-to-inflammatory cell ratio was reduced in positive cases.

Abstract

Introduction

The SARS-CoV-2 virus causes COVID-19 by chiefly infecting the nasal and oral mucosal cavities, where its spike proteins bind to angiotensin-converting enzyme II (ACE2) receptors on epithelial cells. This study aimed to assess SARS-CoV-2-related genotoxicity in buccal mucosal cells through micronuclei counts and 8-Oxo-2'-deoxyguanosine (8-OHdG) expression.

Methods

This cross-sectional study was conducted in 86 COVID-19 suspected patients aged 18-45 years attending an outpatient screening area for reverse transcription polymerase chain reaction (RT-PCR) SARS-CoV-2 testing between December 2023 and February 2024. Salivary swabs were obtained and smeared on glass slides for each patient. These slides were stained to study and compare cellular toxicity by Papanicolaou (Pap) staining and oxidative DNA damage expression by immunohistochemistry. The categorical and continuous variables were assessed using the independent t-test and ANOVA. A p-value of less than 0.05 was considered statistically significant.

Results

The number of micronucleated cells, total micronuclei, neutrophil, lymphocyte and inflammatory cell count in COVID-19 RT-PCR positive patients were 11.32 ± 7.00, 17.32± 12.53, 1.93 ± 1.17, 3.98 ± 2.55 and 5.90 ± 3.15 respectively which is higher than COVID-19 RT-PCR negative individuals 6.09± 3.83, 9.04± 5.82, 0.18± 0.49, 2.13± 0.84 and 2.31±1.01 respectively. Moreover, buccal cells showed increased oxidative DNA damage with intense staining for 8-OHdG in COVID-19-positive patients. The epithelial-to-inflammatory cell ratio was very low in COVID-19-positive buccal smear patients.

Conclusion

This study concludes that SARS-CoV-2 has a genotoxic effect by increasing the micronuclei count and has oxidative DNA damage by increasing the 8-OHdG expression in the exfoliated buccal cells.

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