Possible anti-inflammatory role of bFGF during bovine PGF2α induced luteolysis in relation to iNOS mRNA expression

Abstract

Pro-inflammatory cytokines were shown to be involved in bovine luteolysis. Inducible nitric oxide synthase (iNOS) expression is maximally induced with synergistic combinations of pro-inflammatory cytokines. There is evidence that basic fibroblast growth factor (FGF-2) is involved in the prevention of cytokine-induced inflammation. The corpus luteum is characteristically regressing without any major inflammatory reaction in the surrounding tissue. We investigated the detailed pattern of mRNA expression of the pro-inflammatory cytokines, tumor necrosis factor α (TNFα), interleukin 1β (IL-1β) and interferon γ (IFNγ), and of iNOS and FGF-2 during prostaglandin (PG) F2α induced luteolysis in the bovine corpus luteum (CL). Cows in the mid-luteal phase (days 8–12) were injected with the PGF2α-analogue cloprostenol and CL were collected by transvaginal ovariectomy before and 2, 4, 12, 48 and 64h after PGF2α injection. Conventional and real-time RT-PCR (LightCycler) were employed to determine the mRNA expression for the investigated factors. All cytokines were significantly up-regulated during induced luteolysis. FGF-2 expression increased (P<0.001) during functional luteolysis (until 12h after PGF2α) and diminished thereafter. The mRNA expression for iNOS decreased (P<0.05) after induction of luteolysis. In conclusion, FGF-2 may participate in the suppression of cytokine-induced iNOS mRNA expression and in the prevention of an inflammatory reaction in the surrounding tissues during bovine luteolysis.