# Significance of Hemorheological Tests During Mycoplasma Pulmonis Infection in Laboratory Rats

## TL;DR

This study shows that Mycoplasma pulmonis infection in rats causes significant changes in blood-related parameters, which could help monitor the infection.

## Contribution

This is the first study to describe hemorheological changes caused by Mycoplasma pulmonis infection in laboratory rats.

## Key findings

- Mycoplasma-infected rats showed reduced red blood cell count, hemoglobin, hematocrit, and platelet count.
- Erythrocyte aggregation and deformability were significantly reduced in infected animals.
- Hemorheological changes can serve as indicators for monitoring Mycoplasma infection.

## Abstract

Murine respiratory mycoplasmosis caused by the bacteria Mycoplasma pulmonis (M. pulmonis) is a common disease in wild and laboratory rodents. A natural M. pulmonis infection appeared in an experimental animal facility. Because it is currently unknown whether the infection causes changes in the hematological and hemorheological parameters and that these changes may indicate infection, we aimed to investigate those parameters in laboratory rats. We used the base values of similar-age male and female rats from our previous studies as a control. As a result, we observed several changes in hematological and hemorheological parameters and severe deterioration in the tissue and organs of ill animals. To our knowledge, we are the first to describe that M. pulmonis infection causes significant changes in those variables.

Mycoplasma pulmonis (M. pulmonis) is a chronic infection that can appear in laboratory animal facilities. Deviations in hemorheological parameters during many pathological processes were detected, but it is unknown to what extent M. pulmonis infection causes changes in micro-rheological parameters. We performed our study on 25 symptomatic and asymptomatic Wistar rats, randomly selected from the entire population and presumably infected with Mycoplasma. From the blood samples, we determined the hematological parameters, red blood cell deformability under varying shear stress and varying osmolality, and the degree of red blood cell aggregation. We used the data of age- and sex-matched animals from our previous research as a control. Red blood cell count, hemoglobin, hematocrit values, and platelet count were significantly reduced in Mycoplasma-infected animals. Significantly reduced erythrocyte aggregation and deformability were detected. In conclusion, M. pulmonis infection causes significant changes in hemorheological and hematological parameters. Periodic measurement of these parameters can help monitor the infection.