<i>In vivo</i> evidence for possible up-regulating roles of lysophosphatidic acid around fertilization in rats

Abstract

Lysophosphatidic acid (LPA) produced by autotaxin (ATX) is recognized as a multi-functional mediator in mammalian reproduction. This study focused on possible effect(s) of LPA on ovulated cumulus-oocyte complexes (COCs) around fertilization in rats in vivo. Immunohistochemistry revealed the cell-type-dependent localization of candidates of synthetic enzymes, ATX and two phospholipases A2 isofroms, and LPA receptors LPA1−4 in ovulated COCs and in oviductal epithelium. The eggs ovulated with a form of COCs became denuded of cumulus cells and underwent fragmentation in the absence of fertilization. In vivo experiments of local administration in non-copulated rats demonstrated that eggs denudation was increased by LPA and decreased by anti-ATX antibody and that fragmentation was inhibited by LPA and stimulated by an ATX chemical inhibitor. Furthermore, LPA administration in adult copulated rats increased the rate of cleaved embryos significantly. Obtained results suggest the presence of LPA synthesis and action system in ovulated COCs within the oviductal ampulla and positive actions of LPA possibly at multiple sites around fertilization in rats.

Pathophysiological changes in experimental polycystic ovary syndrome in female albino rats: Using either hemin or L‐arginine

“…Letrozole, a nonsteroidal aromatase inhibitor, reduces the conversion of androgens to estrogens in the ovary, resulting in an increase of testosterone and a decrease of estrogen production. In addition, a low estrogen level weakens the negative feedback on the hypothalamus, resulting in increased gonadotropin-releasing hormone release, which subsequently enhances FSH and LH release (Takeda et al, 2018). The increased LH further stimulates ovarian theca cells to secrete testosterone (Shi & Vine, 2012).…”

Expression of lysophosphatidic acid receptors in the rat uterus: cellular distribution of protein and gestation-associated changes in gene expression

“…Antigenic peptides against which the antibodies were generated had very low and little homology in their amino acid sequence. Immunohistochemical procedure in general was similar to those of the previous reports [17,27,28]. Uteri were instantly fixed in Bouin's solution, dehydrated, and embedded in paraffin.…”

“…To try to identify the subtype(s) and cellular distribution of LPA receptor proteins in rat uteri, immunohistochemistry of LPA1-6 was carried out using antibodies commercially available. The characteristics and sources of the primary antibodies were summarized in Supplementary Table 1 with references that had applied the item for immunohistochemistry [ 17 , 23 , 24 , 26 , 27 , 28 ] and immunocytochemistry. Antigenic peptides against which the antibodies were generated had very low and little homology in their amino acid sequence.…”

Lysophosphatidic acid stimulates rat uterine contraction <i>in vitro</i>

“…Reagents purchased from Cayman Chemical (Ann Arbor, MI, USA) included LPA (1-oleoyl-sn-3-glycerophosphate), sphingosine-1-phosphate (S1P, d18:1), arachidonyl trifluoromethyl ketone (ATK, a group 4A phospholipase A 2 (PLA 2 )-selective inhibitor), NS398 (a COX-2-specific inhibitor), Ki16425 (an LPA1/2/3 antagonist), and PGF 2 α Enzyme Immunoassay (EIA) kit. An oleoyl-LPA was selected among the natural species of LPA, because it has been most frequently used and evaluated in previous studies, including ours [ 12 , 13 ]. Ovine oxytocin and indomethacin (a non-selective COX inhibitor) were purchased from Sigma-Aldrich (St. Louis, MO, USA).…”