Exposure to a Low-Oxygen Environment Causes Implantation Failure and Transcriptomic Shifts in Mouse Uteruses and Ovaries.

Hypoxia is a condition in which tissues of the body do not receive sufficient amounts of oxygen supply. Numerous studies have elucidated the intricate roles of hypoxia and its involvement in both physiological and pathological conditions. This study aimed to clarify the impact of a forced low-oxygen environment in early pregnancy by exposing mice to low-oxygen conditions for 24-72 h after fertilization. The treatment resulted in the complete failure of blastocyst implantation, accompanied by vascular hyperpermeability in the uterus. A transcriptome analysis of the uterus revealed remarkable alterations in gene expression between control normoxic- and hypoxic-treatment groups. These alterations were characterized by the differentially expressed genes categorized into the immune responses and iron coordination. Furthermore, exposure to a low-oxygen environment caused apoptosis in the corpus luteum within the ovary and a reduction in progesterone secretion. Consequently, diminished plasma progesterone levels were considered to contribute to implantation failure in combination with the activation of the hypoxic pathway in the uterus. Additionally, previous studies have demonstrated the impact of hypoxic reactions on blastocyst development and the pre-implantation process in the endometrium. Our findings suggest that the corpus luteum exhibits elevated susceptibility to hypoxia, thereby elucidating a critical aspect of its physiological response.

Transcription Factor 23 is an Essential Determinant of Murine Term Parturition.

Pregnancy involving intricate tissue transformations governed by the progesterone hormone (P4). P4 signaling via P4 receptors (PRs) is vital for endometrial receptivity, decidualization, myometrial quiescence, and labor initiation. This study explored the role of TCF23 as a downstream target of PR during pregnancy. TCF23 was found to be expressed in female reproductive organs, predominantly in uterine stromal and smooth muscle cells. Tcf23 expression was high during midgestation and was specifically regulated by P4, but not estrogen. The Tcf23 knockout (KO) mouse was generated and analyzed. Female KO mice aged 4-6 months exhibited subfertility, reduced litter size, and defective parturition. Uterine histology revealed disrupted myometrial structure, altered collagen organization, and disarrayed smooth muscle sheets at the conceptus sites of KO mice. RNA-Seq analysis of KO myometrium revealed dysregulation of genes associated with cell adhesion and extracellular matrix organization. TCF23 potentially modulates TCF12 activity to mediate cell-cell adhesion and matrix modulation in smooth muscle cells. Overall, TCF23 deficiency leads to impaired myometrial remodeling, causing parturition delay and fetal demise. This study sheds light on the critical role of TCF23 as a dowstream mediator of PR in uterine remodeling, reflecting the importance of cell-cell communication and matrix dynamics in myometrial activation and parturition.

Pomegranate Seeds Extract Possesses a Protective Effect against Tramadol-Induced Testicular Toxicity in Experimental Rats.

Tramadol is a centrally acting opioid analgesic that is extensively used. The chronic exposure to tramadol induces oxidative stress and toxicity especially for patients consuming it several times a day. Previously, we and others reported that tramadol induces testicular damage in rats. This study was conducted to investigate the possible protective effect of pomegranate seed extract (PgSE) against tramadol-induced testicular damage in adult and adolescent rats. Male rats were orally treated with tramadol or in a combination with PgSE for three weeks. Testes were then dissected and analyzed. Histological and ultrastructural examinations indicated that tramadol induced many structural changes in the testes of adult and adolescent rats including hemorrhage of blood vessels, intercellular spaces, interstitial vacuoles, exfoliation of germ cells in lumen, cell apoptosis, chromatin degeneration of elongated spermatids, and malformation of sperm axonemes. Interestingly, these abnormalities were not observed in tramadol/PgSE cotreated rats. The morphometric analysis revealed that tramadol disrupted collagen metabolism by elevating testicular levels of collagen fibers but that was protected in tramadol/PgSE cotreatment at both ages. In addition, DNA ploidy revealed that S phase of the cell cycle was diminished when adult and adolescent rats were treated with tramadol. However, the S phase had a normal cell population in the cotreated adult rats, but adolescent rats had a lower population than controls. Furthermore, the phytochemistry of PgSE revealed a high content of total polyphenols and total flavonoids within this extract; besides, the DPPH free radical scavenging activity was high. In conclusion, this study indicated that PgSE has a prophylactic effect against tramadol-induced testicular damage in both adult and adolescent ages, although the tramadol toxicity was higher in adolescent age to be completely protected. This prophylactic effect might be due to the high antioxidant compounds within the pomegranate seeds.

EFCAB2 is a novel calcium-binding protein in mouse testis and sperm.

Calcium-binding proteins regulate ion metabolism and the necessary signaling pathways for the maturational events of sperm. Our aim is to identify the novel calcium-binding proteins in testis. The gene EFCAB2 (GenBank NM_026626.3, NP_080902.1) was not previously examined, and its properties and exact mechanisms of action are unknown. In this study, we performed phylogenetic and structure prediction analyses of EFCAB2, which displays definitive structural features. Additionally, the distribution, localization, and calcium binding ability of mouse EFCAB2 were investigated. Results revealed extensive conservation of EFCAB2 among different eukaryotic orthologs. The constructed 3D model predicted that mouse EFCAB2 contains seven α-helices and two EF-hand motifs. The first EF-hand motif is located in N-terminal, while the second is located in C-terminal. By aligning the 3D structure of Ca2+-binding loops from EFCAB2 with calmodulin, we predicted six residues that might be involved in Ca2+ binding. The distribution of the Efcab2 mRNA, as determined by northern blotting, was detected only in the testis among mouse tissues. Native and recombinant EFCAB2 protein were detected by western blotting as one band at 20 kDa. In situ hybridization and immunohistochemical analyses showed its localization specifically in spermatogenic cells from primary spermatocytes to elongate spermatids within the seminiferous epithelium, but neither spermatogonia nor somatic cells were expressed. Moreover, EFCAB2 was specifically localized to the principal piece of cauda epididymal sperm flagellum. Furthermore, the analyses of purified recombinant EFCAB2 by Stains-all, ruthenium red staining, and by applying in vitro autoradiography assay showed that the physiological function of this protein is Ca2+ binding. These results suggested that EFCAB2 might be involved in the control of sperm flagellar movement. Altogether, here we describe about EFCAB2 as a novel calcium-binding protein in mouse testis and sperm.