Participation of reactive oxygen species in PGF2alpha-induced apoptosis in rat luteal cells

Abstract

Prostaglandin F(2alpha) (PGF(2alpha)) is implicated in the process of luteal regression in many species. Treatment of rat luteal tissue with PGF(2alpha) increases the generation of reactive oxygen species. Since reactive oxygen species have been implicated in apoptosis, the present study was undertaken to determine whether reactive oxygen species play a role in the PGF(2alpha)-induced apoptosis of rat luteal cells. Rat luteal cells were loaded with 6-carboxy-2, 7'-dichlorodihydro-fluorescein (CDCFH) diacetate, di (acetomethyl ester), which can be oxidized by reactive oxygen species to yield CDCF, a fluorescent molecule, and the cells were treated with different doses of PGF(2alpha). Incubation with 100 micromol PGF(2alpha) l(-1) induced an increase in CDCF fluorescence (P < 0. 05). Treatment of cells with PGF(2alpha) for 48 h in serum-free medium induced a dose-dependent increase in cell death, and these cells exhibited the morphological characteristics typical of apoptosis, including condensed or fragmented nuclei and fragmentation of internucleosomal DNA. Pretreatment of these cells with ascorbic acid, N,N'-dimethylthiourea, or superoxide dismutase, which acts as an antioxidant or a radical scavenger, prevented the PGF(2alpha)-induced apoptosis. These results demonstrate that PGF(2alpha) produces reactive oxygen species and induces apoptosis in rat luteal cells, indicating that the reactive oxygen species may induce apoptotic cell death during luteolysis.

Changes of vitamins A, E, and C and lipid peroxidation status of breeding and pregnant sheep during dry seasons on medium-to-low quality forages

“…The synthesis of collagen during bovine luteal development and maturation is supported by ascorbic acid (Luck and Zhao 1993). Ascorbic acid depletion from ovarian tissue of rat (Aten et al 1992;Sato et al 1974) and pig CL (Petroff et al 1998) is proposed as an early mechanism of luteal regression by rendering luteal cells susceptible to ROS-induced oxidative stress and apoptosis (Tanaka et al 2000). Ovarian levels of ascorbic acid and tocopherol change markedly in the rat in response to luteotropic or luteolytic factors (Aten et al 1992).…”

Essential actions of melatonin in protecting the ovary from oxidative damage

“…The enhancement of ROS accompanied by reduced levels of antioxidant enzymes contributes to oxidative stress-mediated apoptosis, a prerequisite step to luteolysis [91]. Reactive oxygen species and PGF2a act synergistically early in the luteolytic process; PGF2a inhibits steroidogenesis by binding to specific receptors, which in turn induces an increase in intracellular Ca 2þ concentration or an inhibition on cAMP synthesis [92]. Furthermore, PGF2a induces H 2 O 2 generation through mobilization of cytosolic calcium, which inhibits LHstimulated cAMP accumulation and progesterone production, and reduces steroidogenesis by blocking intracellular transport of cholesterol in rat luteal cells [93].…”

Serum levels of reactive oxygen species (ROS) in the bitch

“…(3) Furthermore, both luteal and PMN have been found to generate large amounts of ROS, which seem to be involved in both luteotrofic and luteolitic activities, in diestrus. (9) Besides the above-mentioned ovarian processes, sexual steroid hormones also modulate the production of ROS. In fact, estrogens promote lipid peroxidation in the uterus and mammary gland, at low concentrations, (10,11) whereas, at high levels, they exert an antioxidant effect.…”