Evaluation of in vitro Activation of Bovine Endometrial and Vaginal Epithelial and Blood Mononuclear Cells to Produce Nitric Oxide in Response to Mycoplasma bovis, Mycoplasma bovigenitalium and Ureaplasma diversum

Regiani Nascimento Gagno Pôrto,Marco Antonio de Oliveira Viu,Maria Lucia Gambarini,Ana Paula Junqueira-Kipnis,Rafaela Cavalcanti Teixeira

doi:10.2478/acve-2021-0012

Regiani Nascimento Gagno Pôrto, Marco Antonio de Oliveira Viu + Show 3 more

Open Access

https://doi.org/10.2478/acve-2021-0012

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Abstract

Abstract Genital mycoplasmosis is a condition present in bovine production systems, and the most important agents involved are Mycoplasma bovis, Mycoplasma bovigenitalium and Ureaplasma diversum. Some aspects of their pathogenesis remain unclear. This study was designed in order to evaluate their ability to stimulate mononuclear cells from the endometrium, vagina and peripheral blood of cycling and healthy cows to produce nitric oxide (NO). Cellular cultures of endometrial, vaginal and peripheral blood cells from 33 healthy cows were cultivated with Mycoplasma bovis, Mycoplasma bovigenitalium and Ureaplasma diversum originated from the 4th passage in culture broth and the NO production was measured by the Greiss reaction. Confirmation of the presence of mononuclear cells and of the agents during and after the NO assay was done by Giemsa stained smears and further cultivation and detection by PCR reaction. Mononuclear cells from all samples produced NO. Mycoplasma bovigenitalium stimulated higher NO production than the others (p<0.05). Endometrial cells produced less NO than vaginal or blood cultured cells. In conclusion, it seems that Mycoplasma bovis, Mycoplasma bovigenitalium, and Ureaplasma diversum are able to activate mononuclear cells and induce the production of NO, thus suggesting that this pathway is elicited in response to the primary infection by these agents. More studies are necessary to verify why these agents remain in the bovine reproductive tract for long periods and how they reassume deleterious effects.

Highlights

Mycoplasmas and ureaplasmas are opportunistic pathogens for humans and animals, considered as causal agents of Granular Vulvovaginitis Syndrome in bovines [1]
nitric oxide (NO) production was verified in all cultures, but regardless to the agents, higher NO production was present in cell cultures exposed to Mycoplasma bovigenitalium when compared to Mycoplasma bovis and Ureaplasma diversum
It was suggested that only the bovine macrophages, but not the monocytes, are able to express high levels of iNOS by exposure to bacterial constituents [16], which would explain the lower concentrations of NO found in peripheral blood samples

Summary

Introduction

Mycoplasmas and ureaplasmas are opportunistic pathogens for humans and animals, considered as causal agents of Granular Vulvovaginitis Syndrome in bovines [1]. The occurrence of Mycoplasma bovis, Mycoplasma bovigenitalium and Ureaplasma diversum is linked to infertility and increased numbers of services per conception, early embryo death, and losses during the perinatal period [2]. Because of their capacity to colonize mucosal surfaces of the nose, eye, middle ear, vagina, and mammary gland [3] the dissemination between animals can occur via aerosolization of nasal secretions [4] or ingestion of contaminated colostrum or milk [5]. Due to the limited capacity of biosynthesis, most of the mycoplasmas have a specific form of parasitism in the host and its tissues, and developed mechanisms that allow the interaction with the host’s immune response and colonization of other hosts, and an efficient mechanism of adhesion is requirement for their survival and pathogenicity, avoiding elimination through mucous secretions [9]

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