Effects of increasing lipopolysaccharide concentrations on in vitro developmental competence of ovine oocytes

Abstract

Although a considerable number of studies have investigated the effects of lipopolysaccharide (LPS) on the reproductive performance of dairy cows, the response of ovine oocytes to LPS during their in vitro maturation and development is not well defined yet. Ewe’s ovaries were obtained from a slaughterhouse, the oocytes were collected and matured in the presence of increasing concentrations (0, 0.01, 0.1, 1 and 10 µg/mL) of LPS in order to evaluate the meiotic maturation by measuring the proportion of oocytes reaching the MII stage. The concentration of intracellular glutathione (GSH) was measured in oocytes following maturation in vitro . In addition, concentrations of selected metabolites including glucose, pyruvate, lactate and glutamine were quantified in the medium following maturation. A number of treated matured oocytes along with the control group were subsequently fertilized using frozen semen and assessed for the rate of cleavage and for the proportion reaching the blastocyst stage. The number of oocytes in MII stage was significantly reduced in response to the increasing concentrations of LPS (77.83%, 70.64%, 68.86%, 66.32%, respectively, in case of 0.01, 0.1, 1 and 10 µg/mL LPS when compared to the control group, 76.34%; P<0.05 ). There were no differences neither in the intracellular concentration of GSH in the oocytes nor in case of the metabolites in the maturation medium. Although the rate of cleaved oocytes was not affected by increasing levels of LPS, the blastocyst rate was reduced in a dose dependent manner (36.69%, 34.21%, 30.35%, 17.27% and 14.03% for the control, 0.01, 0.1, 1 and 10 µg/mL LPS, respectively ( P<0.05 ). These results demonstrate that the developmental competence of ovine oocytes may be affected detrimentally by LPS and such deleterious effects could be related to the maturation process.

Developmental Competence of Embryo vis-à-vis Lipopolysaccharide

“…Also, a significantly lower cleavage, morale and blastocyst formation rates were recorded in parthenogenetically activated oocytes on exposure to LPS, however, the apoptotic nuclei have significantly increased in blastocysts. Similar study was conducted in ovine and reported no effect on the cleavage rate of oocytes, however, the blastocyst formation rate has reduced in concentration/dose-dependent manner on increasing the LPS dose (Heydari et al, 2020). LPS (1mg/ml) has significantly (p<0.05) reduced the developmental competence of compaction and blastocyst stages (Mokhtari et al, 2020).…”

“…It was also observed that the LPS increased the proliferation rate in different cell models including epithelial cells from other species through inducing oxidative stress (Chanrot et al, 2017). Recent findings concluded that in vitro exposer of oocytes with LPS affects the oocyte maturation and subsequently embryonic developmental competence through triggering the oxidative stress, pro-apoptotic effects and immune response (Zhao et al, 2017;Rincon et al, 2019;Heydari et al, 2020;Rasekhi et al, 2020).…”

In vitro versus cryo-induced capacitation of bovine spermatozoa, part 1: Structural, functional, and oxidative similarities and differences

“…Each sample was divided into three parts; the first fraction was incubated in physiological saline solution (IMUNA PHARM, a. s., S ˇaris ˇske ´Michal ˇany, Slovakia) in a ratio of 1:40 as the control. The second one was diluted (1:40) and incubated with pre-warmed capacitation medium [10] consisting of sodium chloride, potassium chloride, sodium bicarbonate, sodium phosphate monobasic, HEPES, magnesium and calcium chloride, sodium D-lactate and phenol red for the induction of capacitation under in vitro conditions. The data summarizing the volume of diluents and final concentration of spermatozoa in each sample are available in S1 Table in S1 File.…”

In Vitro versus Cryo-Induced Capacitation of Bovine Spermatozoa, Part 2: Changes in the Expression Patterns of Selected Transmembrane Channels and Protein Kinase A

“…All samples (1 sample per bull) were distributed into three fractions. The first and second ones were immediately transported into the laboratory and incubated for 30 min at 39 °C and 5% concentration of CO 2 , either with physiological saline solution (IMUNA PHARM, A. S., Šarišské Michaľany, Slovakia) as a control or with a capacitation medium consisting of 100 mM sodium chloride (Sigma-Aldrich, St. Louis, MO, USA), 3 mM potassium chloride (Sigma-Aldrich, St. Louis, MO, USA), 25 mM sodium bicarbonate (Sigma-Aldrich, St. Louis, MO, USA), 283 µM sodium phosphate (Sigma-Aldrich, St. Louis, MO, USA), 10 mM HEPES (Sigma-Aldrich, St. Louis, MO, USA), 1.5 mM magnesium chloride (Sigma-Aldrich, St. Louis, MO, USA), 2.5 mM calcium chloride (Sigma-Aldrich, St. Louis, MO, USA), 0.37% sodium DL-lactate solution (60%; Sigma-Aldrich, St. Louis, MO, USA) and 0.2% phenol red solution (0.5%; Sigma-Aldrich, St. Louis, MO, USA) [ 84 ] diluted in a ratio of 1:40. The third part was cryopreserved for further investigation.…”