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The corpus luteum plays a fundamental role in regulating reproduction via progesterone production. Still, there is little data on factors regulating the maintenance of luteal function during early pregnancy in gilts. Previous studies emphasize the role of hypoxia and HIF-1 in the regulation of steroidogenic and angiogenic genes expression and progesterone production by ovarian cells. Using the corpus luteum of cyclic and early pregnant gilts we analyzed: (1) the in vitro effects of reduced oxygen tension on progesterone production and mRNA expression of HIF1A and luteal function regulators, STAR and VEGFA; (2) the ex vivo profiles of mRNA and protein expression of HIF-1α, STAR, VEGFA and transcription factors-cJUN and CREB, regulating STAR expression, in the corpus luteum of cyclic and pregnant gilts. The synthesis of progesterone was gradually inhibited in cyclic or pregnant gilt luteal tissue (on day 13 of cycle or pregnancy) incubated in a decreasing concentration−20%, 10%, and 3% of oxygen (O2). Luteal tissues of pregnant gilts produced trace amounts of progesterone in 10% O2, which was similar to cyclic gilts in 3% O2. HIF1A expression increased after 24 h of incubation in tissues of cyclic gilts in 3% vs. 20% O2 (p < 0.01), whereas levels of STAR and VEGFA increased significantly in cyclic and pregnant gilt tissues incubated in 10% and 3% vs. 20% O2. The ex vivo mRNA expression of HIF1A and VEGFA was elevated (p < 0.001) on day 14 vs. day 12 of pregnancy. The protein expression of HIF-1 and VEGFA increased (p < 0.001), whereas the level of STAR (mRNA and protein) and progesterone dropped (p < 0.001) on day 14 of the estrous cycle vs. a parallel day of pregnancy and/or day 12 of the estrous cycle. The content of phosphorylated cJUN and CREB was elevated (p < 0.01) in the luteal tissue on day 12 or 14 of pregnancy vs. parallel days of the estrous cycle. These increases of phosphorylated cJUN and CREB may be involved in STAR expression in the luteal tissue during early pregnancy in gilts.

The routine procedure of estrous cycle synchronization in pigs allows for the use of gonadotropins to stimulate ovarian activity. The applied protocols of eCG and hFSH priming similarly affected development of ovarian follicles in two classes 3–6 mm and >6 mm of diameter, however, the number of small follicles (p = 0.04)- and r-hCG (p = 0.049)-stimulated follicular walls of mature gilts than in prepubertal hFSH-primed gilts. Both ovulatory triggers decreased the abundance of LHCG/FSH mRNA receptors in follicular walls, which mimic downregulation of these receptors by a preovulatory LH surge, confirmed in vivo. These data revealed the importance of sexual maturity in the protection of the estrogenic environment, and the selective, moderate role of eCG and FSH in the activation of steroidogenic enzymes in preovulatory follicles.

Introduction: The World Health Assembly adopted the Global Health Strategy and aims to reduce the incidence of Hepatitis from up to 10 million cases per year to 0.9 million cases and to reduce deaths from 1.4 million to 0.5 million per year by 2030. However, given the prevalence of chronic Hepatitis B in many countries and the incidence of new cases of acute Hepatitis B, the task is not easy. This study investigates the trends and determinants of the incidence of acute Hepatitis B in Poland in 2005–2019. Materials and Methods: Data on the incidence of acute hepatitis B (AHBV) were obtained from the National Institute of Public Health. A case definition for AHBV was consistent with the EU definition. The incidence trends were determined by considering the sex, age and place of residence. Due to the exponential dependence model, the computations were based on the logarithm of the incidence rate. This allowed for the transformation to linear form and analysis could be conducted using linear models. Pearson’s correlation was used to determine the linear trend of incidence in general and according to sex and place of residence. The values of incidence rates (independent proportions test) and the coefficients illustrating the trends under study were also compared among males and females as well as urban and rural residents. Results: The incidence of AHBV in the Polish population decreased with similar slopes in both sexes. The newly reported cases of AHBV were more frequent in the male population. The incidence of acute Hepatitis B in the urban population was significantly higher than in the rural population. The significant decreasing trends in incidence were observed in all age ranges, with the exception of two age ranges 0–4 and 10–14, where the total incidence during the whole study period was negligible. Conclusion: Despite the significant decrease in the incidence of AHBV in Poland and its position among the European countries with the lowest hepatitis B (HBV) incidence, the alarmingly high proportion of iatrogenic infections requires further improvement in the sanitary condition of health care facilities. It is also necessary to decrease the number of unvaccinated individuals.