Frontiers in Physiology (Jun 2022)

SARS-CoV-2 Nucleocapsid Protein is Associated With Lower Testosterone Levels: An Experimental Study

  • Caio Henrique Lucio Carrasco,
  • Caio Henrique Lucio Carrasco,
  • Paloma Noda,
  • Ana Paula Barbosa,
  • Everidiene Kinverlly Vieira Borges da Silva,
  • Camila Gasque Bomfim,
  • Bianca Helena Ventura Fernandes,
  • Thiago Afonso Teixeira,
  • Thiago Afonso Teixeira,
  • Amaro Nunes Duarte Neto,
  • Paulo Hilario Nascimento Saldiva,
  • Paulo Hilario Nascimento Saldiva,
  • Kamal Achoa Filho,
  • Cristiane Rodrigues Guzzo,
  • Edison Luiz Durigon,
  • Fernando Luiz Affonso Fonseca,
  • Roseli Corazzini,
  • Camilla Fanelli,
  • Irene Lourdes Noronha,
  • Jorge Hallak,
  • Jorge Hallak,
  • Jorge Hallak,
  • Jorge Hallak

DOI
https://doi.org/10.3389/fphys.2022.867444
Journal volume & issue
Vol. 13

Abstract

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The ongoing COVID-19 pandemic represents an extra burden in the majority of public and private health systems worldwide beyond the most pessimistic expectations, driving an urgent rush to develop effective vaccines and effective medical treatments against the SARS-CoV-2 pandemic. The Nucleocapsid structural viral protein is remarkably immunogenic and hugely expressed during infection. High IgG antibodies against Nucleocapsid protein (N protein) levels were detected in the serum of COVID-19 patients, confirming its pivotal antigen role for a T lymphocyte response in a vaccine microenvironment. Currently, adverse events associated with immunizations have raised some degree of concern, irrespective of its huge benefits in dealing with disease severity and decreasing mortality and morbidity. This hitherto study evaluates histological changes in rats’ testes, epididymis, prostate, and seminal vesicles and analyzes hormone levels after solely N protein inoculation. Therefore, we exposed a group of Lewis rats to weekly injections of the recombinant N protein for 28 days, while a control group was inoculated with a buffer solution. The N group revealed a more significant number of spermatozoa. Spermatozoa in the seminiferous tubules were counted in twenty 400 × microscopy fields (mean of 9.2 vs. 4.6 in the control group; p < 0,01), but significantly lower testosterone levels (mean of 125.70 ng/dl vs. 309,00 ng/dl in the control group; p < 0,05) were found. No other histological and biochemical changes were displayed. Conclusively, these data suggest testicular hormonal imbalance mediated by the SARS-CoV-2 N protein that could be linked to reported post-COVID-19 syndrome hypogonadism. More relevant research might be performed to confirm this viral antigen’s deleterious mechanism in the human testicular microenvironment, particular in Leydig cell function.

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