&lt;i&gt;In Vitro&lt;/i&gt; Assessment of Progesterone and Prostaglandin E&lt;sub&gt;2&lt;/sub&gt; Production by the Corpus Luteum in Cattle Following Pharmacological Synchronization of Estrus

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Abstract. We have previously documented synthesis of lysophosphatidic acid (LPA) in the bovine endometrium and the increased presence of LPA receptor mRNA expression during pregnancy. Therefore, LPA could contribute to early pregnancy establishment in the cow. In the present study, we investigated the effect of intravaginally administered LPA on pregnancy rates and on the plasma levels of progesterone (P4) and prostaglandins (PGs) in heifers. Animals were inseminated and from day 15 to 18 after estrus were treated intravaginally with saline, LPA (1 mg) or LPA receptor blocker (VPC32183; 1 mg). Blood samples were collected on days 0,6,12,15,16,17,18 and 21 after insemination. Pregnancy was confirmed by ultrasonography and per rectum examination on days 30 and 49-50 after insemination. Intravaginal LPA administration increased the plasma P4 and PGE2 concentrations compared with saline and VPC32183-treated heifers. In the saline and LPA-treated groups, 6 out of 8 heifers were pregnant (75%), whereas the pregnancy rate in the VPC32183-treated heifers was only 37%. We also examined the effects of LPA on PG secretion and PG synthase mRNA expression in stromal and epithelial cells of the bovine endometrium on days 16-18 of pregnancy and the estrous cycle. LPA increased PGE2 production and PGE2 synthase (PGES) mRNA expression in stromal cells during the estrous cycle and pregnancy. On Days 16-18 of pregnancy, LPA inhibited PGF2α production and PGFS mRNA expression in epithelial cells. The results suggest that LPA serves as a luteotropic factor during the estrous cycle and pregnancy, stimulating P4 secretion in vivo and PGE2 secretion in vitro through activation of PGES mRNA expression in stromal cells. Moreover, during the early pregnancy, LPA decreases PGF2α synthesis and mRNA expression for PGFS in epithelial cells of the bovine endometrium. Key words: Cow, Lysophosphatidic acid, Pregnancy, Progesterone, Prostaglandins (J. Reprod. Dev. 56: [411][412][413][414][415][416][417][418][419][420] 2010) he role of lysophosphatidic acid (LPA) in the reproductive system has been studied extensively in mice [1], pigs [2,3], ewes [4] and cows [5][6][7]. We found that in the bovine endometrium, in contrast to the mouse, pig and sheep [1][2][3][4], there is mRNA expression only for the LPA receptor type 1 (LPAR1) [5]. We also demonstrated that LPA is locally produced and released from the bovine endometrium [5]. The LPA concentration and expression of mRNA for LPAR1 in the bovine endometrium are significantly higher during early pregnancy than during the estrous cycle. Moreover, LPA administered into the aorta abdominalis stimulated progesterone (P4) and prostaglandin (PG) E2 secretion during the luteal phase of the estrous cycle in vivo. This LPA-mediated stimulation of PGE2 synthesis might serve as an additional luteotropic factor during the luteal phase of the estrous cycle and on days 8-10 of early pregnancy. However, during early pregnancy, on days 8-10 after conception in the cow, LPA may play an even more important role b...

Section: Animalsmentioning

confidence: 99%

mentioning

confidence: 99%

Lysophosphatidic Acid Action During Early Pregnancy in the Cow: In Vivo and In Vitro Studies

Wocławek-Potocka

Kowalczyk-Zięba

Skarzynski

2010

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“…On the other hand, large arteriolovenous vessels remained intact and exhibited a thickening wall in the regressing CL, suggesting that arteriolovenous vessels may have a role in the expeditious disrupture of the bovine CL. Further studies will be needed to clarify the physiological meaning for the increase in arteriolovenous blood vessels in the regressing CL.It is well considered that spontaneous luteolysis induced by endogenous PGF2α and pharmacological luteolysis induced by administration of exogenous PGF2α are different [28][29][30]. In fact, Skarzynski et al recently reported that estrus synchronization, depending on the method and PGF2α analogue, may induce lower P production and decrease the sensitivity of the CL to luteotropic factors compared with those in the spontaneous estrous cycle in the cow [30].…”

mentioning

confidence: 99%

Distribution of Arteriolovenous Vessels, Capillaries and eNOS Expression in the Bovine Corpus Luteum During the Estrous Cycle: a Possible Implication of Different Sensitivity by Luteal Phase to PGF2.ALPHA. in the Increase of Luteal Blood Flow

Shirasuna

Asahi

Sasaki

et al. 2010

Abstract. We have shown that luteal blood flow increases in the peripheral vasculature of the mature corpus luteum (CL) prior to the onset of luteolysis in response to prostaglandin F2α (PGF2α) in the cow, but this phenomenon does not occur in the early CL. We therefore hypothesize that this acute increase of luteal blood flow occurs by vasodilation of large blood vessels due to local release of nitric oxide (NO). In the present study, we characterized the CL vasculature together with endothelial NO synthase (eNOS) expression during the estrous cycle in the cow. Immunohistochemistry was used to quantify the number of arteriolovenous vessels (surrounded with smooth muscle actin-positive smooth muscle cells), capillaries (with von Willebrand Factor-positive endothelial cells) and eNOS protein. The arteriolovenous vessels existed more in the periphery of the matured CL (mid, late and regressing CL) than in the center region. In the early CL, there were as many arteriolovenous vessels in the periphery as in the center, while more capillaries existed in the center than in the periphery of the mid and late CL. Also, eNOS protein existed in the periphery more than in the center of the matured CL. These results indicate that the early CL has a homogeneous vascular and eNOS distribution. In contrast, the matured CL is a heterogeneous organ having a higher vascular and eNOS distribution in the periphery than in the center. In conclusion, the distribution of arteriolovenous vessels and eNOS in the matured CL was higher in the periphery than in the center of the CL. Thus, this suggests that this structural change from the early (homogeneous) to the mid (heterogeneous) luteal phase is related to the difference in the CL response of blood flow increase due to PGF2α, which is only observed in the mature CL. Key words: Blood vessels, Corpus luteum, eNOS, Luteolysis (J. Reprod. Dev. 56: [124][125][126][127][128][129][130] 2010) rich vascular network is established within the corpus luteum (CL) in order to enable it to function as an endocrine gland. Although the CL is constituted of several types of cells, such as luteal cells, endothelial cells and smooth muscle cells, vascular endothelial cells account for up to 50% of the bovine mature CL [1,2]. Moreover, endothelin-1 (EDN1) and angiotensin II (Ang II) secreted by endothelial cells in the CL have been shown to inhibit progesterone secretion from luteal cells [3][4][5]. These findings indicate that luteal blood vessels have a key role in regulation of luteal function.Functionally, luteal blood vessels can be divided roughly into two types of blood vessels. One of these types is an arteriolovenous vessels, i.e., arteriola and venula vessels, which have a smooth muscle layer and receive the vasorelaxant effect. In general, the diameter of an arteriola is about 40 μm (from 20 μm to 100 μm), and the arteriola has an important role in creation of peripheral resistance for local blood flow. In the circulation of blood, the arteriola connects to microcapillary vessels followed by ...

“…The animals were eliminated by the owner from two dairy cow herds (Years 2004(Years -2006) because of their low milk production. Estrus was synchronized in the cows using double injections of an analogue of PGF2α (dinoprost, Dinolytic; Pharmacia & Upjohn N.V.S.A., Belgium), as described recently by Skarzynski et al [35] for estrus synchronization of multiparous cows. The onset of estrus was determined by observing the signs of estrus (i.e., vaginal mucus, standing behavior) and was confirmed by a veterinarian via ultrasonography (USG) examination using DRAMINSKI Animal profi Scanner (Draminski Electronics in Agriculture, Olsztyn, Poland; www.draminski.com) and per rectum examination.…”

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confidence: 99%

Lysophosphatic Acid Modulates Prostaglandin Secretion in the Bovine Endometrial Cells Differently on Days 8-10 of the Estrous Cycle and Early Pregnancy

Wocławek-Potocka

Brzezicka

Skarzynski

2009

Abstract. Lysophosphatidic acid (LPA) is becoming a new player in regulation of the reproductive processes of domestic animals. In the present study, we examined whether LPA modulates prostaglandin (PG) synthesis in the bovine endometrium at the time of the early maternal pregnancy recognition compared with the respective days of the estrous cycle and the enzymatic mechanism of this action. Bovine epithelial and stromal endometrial cells isolated from the uteri on days 8-10 of the estrous cycle and pregnancy were cultured with LPA for 24 h. LPA increased PGE2 production in stromal cells during the estrous cycle and early pregnancy. On days 8-10 of pregnancy, LPA inhibited PGF2α production in epithelial cells. LPA stimulated PGES mRNA expression in stromal cells during both examined phases and inhibited PGFS mRNA expression in epithelial cells on days 8-10 of pregnancy. The overall results indicate that LPA may serve as a luteotropic factor during the luteal phase of the estrous cycle and early pregnancy stimulating PGE2 synthesis and mRNA expression for PGES in stromal cells. Moreover, during early pregnancy, LPA might protect bovine CL and early embryo development by decreasing PGF2α synthesis and mRNA expression for PGFS in the epithelial cells of the bovine endometrium. Key words: Cow, Lysophosphatidic acid, Prostaglandins, Uterus (J. Reprod. Dev. 55: [393][394][395][396][397][398][399] 2009) ysophosphatidic acid (LPA), a simple phospholipid, has a vast variety of physiological and pathological actions, such as cell proliferation and differentiation [1,2], cytoskeletal rearrangement [3], cell-to-cell interactions [4] and tumorigenesis [5,6]. In the literature, at least two pathways of LPA synthesis have been postulated [7,8]. In serum and plasma, LPA is mainly converted from lysophospholipids [8]. By contrast, in platelets and some cancer cells, LPA is converted from phosphatidic acid. In each pathway, at least two phospholipase activities are required; phospholipase A1 (PLA1)/PLA2 plus lysophospholipase D (lysoPLD) activities are involved in the first pathway, and phospholipase D (PLD) plus PLA1/PLA2 activities are involved in the second pathway [7]. In the reproductive system, the LPA role has been studied extensively so far. We have recently found that in the bovine endometrium, unlike in mice, pigs and sheep [9][10][11][12], there is only mRNA expression for the receptor for LPA type 1 (LPA1) [13]. We also found that LPA is locally produced and released from the bovine endometrium [13]. The lysophosphatidic acid concentration and expression of mRNA for LPA1 in the bovine endometrium are significantly higher during early pregnancy than during the estrous cycle. Moreover, LPA stimulates progesterone (P4) and prostaglandin (PG) E2 secretion in vivo, and its receptor gene expression (LPA1) is positively correlated with expression of the enzyme responsible for luteotropic PGE2 production (PGES) in the bovine endometrium during the estrous cycle and early pregnancy. These data indicate that LPA may play auto...