No abstract

The porcine myometrium possesses steroidogenic activity. LH and FSH are hypothesised to regulate the myometrial production of androstenedione (A4), testosterone (T), oestrone (E1) and 17β-oestradiol (E2). In this study, we used myometrium collected from cycling (n=15) and pregnant (n=15) pigs on Days 10–11, 12–13 and 15–16 of the oestrous cycle or pregnancy to determine: (1) the abundance of LH and FSH receptor (LH/choriogonadotrophin receptor (CGR) and FSHR) mRNA and protein; (2) activity of 17β-hydroxysteroid dehydrogenase 1 (17βHSD1); and (3) A4, T, E1 and E2 release in response to LH and FSH treatment, used at doses 10 or 100ng mL−1 for 6h. In results, the myometrium possesses LH/CGR and FSHR with minor alterations in their expression in the course of the oestrous cycle or early pregnancy. 17βHSD1 activity was the highest on Days 12–13 of the oestrous cycle and the lowest on Days 15–16 of the oestrus cycle and pregnancy, when compared to the other studied days of the oestrous cycle or pregnancy. The LH and FSH treatment increased A4 release on Days 12–13 of the oestrous cycle, and E1 and E2 release on Days 15–16 of the oestrous cycle. Moreover, on Days 12–13 E2 release was increased in response to FSH treatment (100ng mL−1) in cycling pigs and in response to LH (100ng mL−1) in pregnant pigs. In conclusion, the myometrium of pregnant and non-pregnant pigs expresses LH/CGR and FSHR and has 17βHSD1 activity. In addition, the amount of A4, E1, and E2 release from the myometrium is altered in response to LH and FSH, especially in cycling pigs. LH and FSH appear to be important regulators of myometrial oestrogen release in pigs mostly during luteolysis.

The electromagnetic field (EMF) affects the physiological processes in mammals, but the molecular background of the observed alterations remains not well established. In this study was tested the effect of short duration (2 h) of the EMF treatment (50 Hz, 8 mT) on global transcriptomic alterations in the myometrium of pigs during the peri-implantation period using next-generation sequencing. As a result, the EMF treatment affected the expression of 215 transcript active regions (TARs), and among them, the assigned gene protein-coding biotype possessed 90 ones (differentially expressed genes, DEGs), categorized mostly to gene ontology terms connected with defense and immune responses, and secretion and export. Evaluated DEGs enrich the KEGG TNF signaling pathway, and regulation of IFNA signaling and interferon-alpha/beta signaling REACTOME pathways. There were evaluated 12 differentially expressed long non-coding RNAs (DE-lnc-RNAs) and 182 predicted single nucleotide variants (SNVs) substitutions within RNA editing sites. In conclusion, the EMF treatment in the myometrium collected during the peri-implantation period affects the expression of genes involved in defense and immune responses. The study also gives new insight into the mechanisms of the EMF action in the regulation of the transcriptomic profile through lnc-RNAs and SNVs.

Porcine myometrium possesses steroidogenic activity but its regulation is not well understood. It was hypothesized that the regulators of myometrial steroidogenesis are insulin-like growth factor 1 (IGF-1) and epidermal growth factor (EGF), which were found to modulate the steroidogenic activity of the endometrium and embryos. Myometrial slices were collected from gravid and nongravid pigs on days 10 or 11, 12 or 13 and 15 or 16 and studied for: (1) the relative abundance of IGF-1R and EGFR mRNA transcripts and proteins, to determine myometrial readiness to response growth factors treatment and (2) the effect of IGF-1 or EGF on the myometrial release of androstenedione (A4), testosterone (T), estrone (E1) and estradiol-17β (E2). The results showed that the relative expression and abundance of IGF-1R and EGFR in the myometrium were altered regarding the female reproductive status. During the estrous cycle, EGF increased myometrial release of A4 on days 12–13 and E2 on days 15–16. In gravid pigs (days 15–16), IGF-1 and EGF increased the E1 release. In conclusion: (1) porcine myometrium possesses the potential to respond to IGF-1 and EGF treatment, (2) EGF significantly increases myometrial A4 and E2 release in cyclic pigs, while IGF-1 and EGF increase the E1 release in gravid pigs.

An electromagnetic field (EMF) may affect the functions of uterine tissues. This study hypothesized that EMF changes the estrogenic activity of pig myometrium during the peri-implantation period. Tissue was collected on days 15–16 of the gestation and incubated in the presence of EMF (50 and 120 Hz, 2 and 4 h). The cytochrome P450 aromatase type 3 (CYP19A3) and hydroxysteroid 17β dehydrogenase type 4 (HSD17B4) mRNA transcript abundance, cytochrome P450arom (aromatase), and 17β hydroxysteroid dehydrogenase 17βHSD) protein abundance and estrone (E1) and estradiol-17β (E2) release were examined using Real-Time PCR, Western blot and radioimmunoassay. Selected myometrial slices were treated with progesterone (P4) to determine whether it functions as a protector against EMF. CYP19A3 mRNA transcript abundance in slices treated with EMF was less at 50 Hz (2 h) and greater at 120 Hz (2 and 4 h). HSD17B4 mRNA transcript was greater in slices treated with EMF at 120 Hz (2 h). Progesterone diminished EMF-related effects on CYP19A3 and HSD17B4. When P4 was added, EMF had suppressive (50 and 120 Hz, 2 h) or enhancing (50 Hz, 4 h) effects on aromatase abundance. The E1 release was lower after 4 h of EMF treatment at 50 Hz and P4 did not protect myometrial E1 release. In conclusion, EMF alters the synthesis and release of E1 and did not affect E2 release in the myometrium during the peri-implantation period.