Is interleukin-1α a luteotrophic or luteolytic agent in cattle?

Abstract

Cytokines are thought to regulate prostaglandin (PG) secretion in the bovine endometrium. However, there is no consensus about the role of interleukin-1a (IL1A) on PG secretion. The objective of this study was to examine the influence of IL1A on basal and interferon-t (IFNT)-regulated PG in vitro secretion, as well its effects on PG secretion, progesterone (P 4 ) output, and corpus luteum (CL) in vivo lifespan. Explants of bovine endometrium (days 16-17 of the estrous cycle or early pregnancy) were stimulated with IL1A (10 ng/ml), IFNT (30 ng/ml), or IL1A combined with IFN. IL1A alone strongly stimulated luteotrophic PGE 2 secretion by endometrial tissues of both pregnant and nonpregnant cows. IL1A also stimulated luteolytic PGF 2a output in the late luteal phase. IFNT augmented the stimulatory effect of IL1A on PGE 2 secretion. In an in vivo experiment, saline or IL1A at different doses (0.001-10 mg/per animal) was applied to the uterine lumen on day 16 of the cycle. Only the highest dose of IL1A caused a temporal increase in PGF 2a secretion, while it had no effect on P 4 secretion or CL lifespan. Application of 0.1 and 1 mg IL1A stimulated P 4 and PGE 2 output and prolonged the CL lifespan. Although IL1A may stimulate in vitro luteolytic PGF 2a secretion during the estrous cycle, it only acts as a luteotrophic factor in vivo. IL1A increased luteotrophic PGE 2 and P 4 output, inhibiting spontaneous luteolysis. These luteotrophic effects may result in appropriate luteal development and function in cows during the estrous cycle and early pregnancy.

Prostaglandin F2α promotes angiogenesis and embryo–maternal interactions during implantation

“…This cytokine regulates PG secretion in several organs and tissues (Takács et al 1988). In cattle, IL1A stimulates PGF2α synthesis and secretion by endometrium in vitro and in vivo (Tanikawa et al 2005, Majewska et al 2010. Our results indicate that PGF2α increased IL1A mRNA expression in porcine endometrium.…”

Lipopolysaccharides, cytokines, and nitric oxide affect secretion of prostaglandins and leukotrienes by bovine mammary gland during experimentally induced mastitis in vivo and in vitro

“…Both IL-1a and IL-1-beta messenger RNA expressions have been detected in normal bovine milk cells [25] and in epithelial cells from bovine mammary gland infected with E coli [26]. Besides acting as an immune mediator, IL-1a is one of the main cytokines governing local regulation reproductive events, playing roles in maintenance of corpus luteum (CL) and regulating the local PGE 2 :PGF 2a ratio in bovine endometrium during the estrous cycle [27,28].…”

“…In fact, the relative proportion between both PG syntheses may be more relevant than absolute levels of each individual PG. Moreover, it has been previously reported that direct administration of IL-1a into the uterus during late luteal stage of the estrous cycle significantly stimulates PGE 2 output and prolongs bovine CL lifespan [27]. This might suggest that in vivo IL-1a may play a luteoprotective role.…”

Impairment of the Interleukin System in Equine Endometrium During the Course of Endometrosis1

“…In fact, IL may be responsible for disturbances in physiological processes in endometrium, contributing to impairment of CL maintenance, cell proliferation, and angiogenesis during the estrous cycle, and to early embryo loss. Studies on the association of IL with PGs, in species other than the horse, showed that they may be among the most important components of physiological changes in estrous cycle regulation [12][13][14][15][16]. Furthermore, in the peri-implantation period, ILs participate in conducting several processes, including differentiation of endometrial cells and vascular endothelial cell changes, that accompany implantation and subsequent placental development.…”

“…Interleukin (IL) 1a and IL1b or IL6 are known to take part in regulation of the estrous cycle by modulation of PG synthesis in species other than the horse [12][13][14][15][16]. In particular, IL1a seems to be a potent luteotropic factor supporting early pregnancy development through stimulation of P 4 and PGE 2 production in the cow [14]. Nevertheless, there is almost no information about the role and expression of these cytokines during the estrous cycle or in the mare.…”