A study by the University of São Paulo (USP) that has just been published in the journal ACS Pharmacology & Translational Science it could be an important step towards discovering a Covid-19 treatment. Through lung epithelial cells infected with the new coronavirus, the researchers were able to unravel the biochemical mechanism by which hypertonic saline solution inhibits the replication of SARS-CoV-2. If the effectiveness is proven in clinical trials, the discovery may contribute to new prevention strategies and even the development of treatments for the disease. “We believe that it would be important to advance in this study and carry out tests in humans to verify the effectiveness of the use of spray and nebulization with hypertonic sodium chloride solution [NaCl] as a form of prophylaxis, helping to reduce the spread of the virus in the infected organism and to reduce the chances of more severe inflammation”, says Cristiane Guzzo, a researcher at the Institute of Biomedical Sciences at the University of São Paulo, author of the work.
By comparing different concentrations of the product, the scientists found that the use of the 1.5% NaCl solution inhibited, in vitro, the replication of SARS-CoV-2 by 100% in guinea pig cells. In tests with human lung epithelial cells, the 1.1% solution was sufficient to prevent the virus from replicating in 88%. “Once we were able to explain this intracellular response mechanism to the hypertonic solution, we carried out a study with clear applications in health and in the understanding of different respiratory diseases”, explains Henning Ulrich, from the Institute of Chemistry (IQ-USP), also author of the research.
According to Ulrich, this result observed in the case of SARS-CoV-2 is likely to be repeated with other viruses, as it is a host cell mechanism, from which the microorganism takes proteins and energy sources to replicate itself. . In the study, researchers suggest testing two types of use of hypertonic NaCl solution. As a nasal spray for airway prophylaxis, entry point for SARS-CoV-2 into the body and through nebulization to deliver the serum to the lung. In this case, it is essential to apply the right concentrations of NaCl for the effectiveness of the method, which can only be evaluated through clinical tests in patients with Covid-19 – it is noteworthy that nebulization with hypertonic solution is already used to treat children with bronchiolitis , for example. “It would be a treatment used in the first days of infection. Reducing virus replication means reducing the severity of the disease and the inflammatory aggravation because Covid-19 is complex”, emphasizes Guzzo. “There is the viral replication part – that the saline solution would have an effect – and also the systemic inflammation part, which goes beyond. This second phase, when started, can be intense and generate a series of other complications in different organs”, he warns.
With the participation of researcher Edison Durigon and support from FAPESP, the research highlights that, although the evidence suggests that the use of a sodium chloride solution inhibits virus replication, it does not represent total protection against infection. “It’s a very simple and inexpensive measure that could minimize the severity of Covid-19 by reducing the viral load. It could be added to safety protocols, without replacing the use of masks, social distance or the need for vaccination”, concludes the researcher.