Toxoplasma gondii infection reduces serum progesterone levels and adverse effects at the maternal‐foetal interface

Abstract

Aims Pregnant BALB/c mice infected with a Toxoplasma gondii type II strain were used to determine how pregnancy interferes with the development of maternal immunity to T gondii and how infection disrupts pregnancy and foetal development. Methods Maternal and foetal parasite loads were assessed by amplification of T gondii SAG1 using qPCR. Adverse effects of infection were evaluated on foetal‐placental development by quantification of implantation units undergoing resorption and by histopathological analyses. Serum progesterone levels were quantified by immunoassay. The effect of T gondii infection on maternal immunity was determined by assessing the cellular composition of spleens by flow cytometry. Results Infected pregnant mice exhibited clinical signs of infection, inflammation and necrosis at the maternal‐foetal interface and decreased serum progesterone levels. In infected mice, there was a clear effect of pregnancy and infection on macrophage cell numbers. However, no differences in the parasite load were detected between non‐pregnant and pregnant mice. Conclusions Maternal T gondii infection induced adverse effects at the maternal‐foetal interface. Alterations were found in immune spleen cells, dependent on the day of pregnancy, relative to nonpregnant animals. The results obtained suggest a pregnancy‐dependent mechanism during T gondii infection able to interfere with macrophage numbers.

Establishment of a murine model of congenital toxoplasmosis and validation of a qPCR assay to assess the parasite load in maternal and fetal tissues

“…It is known that the size of the placenta, such as thickness and surface area, reflects its function and efficiency and that a reduction in these measures can lead to abnormal fetal growth (Liu et al, 2021). Therefore, the reduction in placental surface area observed in our model and others can be attributed to vertical T. gondii infection, which could explain the fetal growth abnormalities described here and elsewhere (Brito et al, 2020). Of note, we observed that some placentas had a pale brown color instead of the bright red color found in the healthy organ.…”

“…We showed that the placental areas of inoculum 10 7 were slightly but significantly smaller than those obtained from uninfected SW dams. Accordingly, a slight reduction in placental size area, along with decreased placental weights, was observed in BALB/c mice infected intraperitoneally at day 7 of gestation with 5 × 10 3 ME49 tachyzoites and analyzed 1 week later (Brito et al, 2020). It is known that the size of the placenta, such as thickness and surface area, reflects its function and efficiency and that a reduction in these measures can lead to abnormal fetal growth (Liu et al, 2021).…”

“…Several models of congenital toxoplasmosis have been established over time, both with inbred and outbred mice (Pfaff et al, 2008;Pezerico et al, 2009;Senegas et al, 2009;Vargas-Villavicencio et al, 2016a,b, 2022Sharif et al, 2018;Wang et al, 2018;Brito et al, 2020). In general, inbred mice are often preferred in comparison to outbred mice across biomedicine, since the assumption that they are less variable, more repeatable, and better defined than outbred stocks.…”

The Role and Function of Regulatory T Cells in Toxoplasma gondii-Induced Adverse Pregnancy Outcomes

“…Brito et al infected BALB/c mice with T. gondii type II strain (ME49) [ 22 ]. Histopathological analysis showed that T. gondii was generally detected in the muscularis at the early gestation period, and a small number of T. gondii were found in the decidua on the 14th day of gestation.…”

Ecological relationships among habitat type, food nutrients, parasites and hormones in wild boar Sus scrofa during winter

“…Progesterone (P) plays critically important roles in vertebrate physiology, especially reproduction (Orlando and Ellestad 2014). Previous studies have extensively reported the negative relationship between T3 or P and parasites and positive relationships between COR or P and parasites (Khalil et al 2011, Carlsson et al 2016, Chethan et al 2016, Hernandez et al 2018, Brito et al 2019. Thus, there are interactions between nutrients and hormones, and both nutrient and hormone levels may be crucial for resistance to parasites.…”