Evaluation of serum concentrations of tumor necrosis factor (TNF)-α, interleukin (IL)-2, IL-10, and nitric oxide (NO) during the estrous cycle, early pregnancy and abortion in goats

The aim of this study was to establish the serum concentrations, ranges, and trends of Thl type cytokine (tumor necrosis factor (TNF)-alpha and interleukin (IL)-2), Th2 type cytokine (IL 10), and nitric oxide (NO) during the estrous cycle, early pregnancy and abortion in goats. Boer goats (n = 25) having symptoms of normal estrous cycles were selected, 20 were mated and 15 conceived a pregnancy, and the remaining five were not mated and served as estrous controls. On the Day 60 of pregnancy, all 15 pregnant goats were induced to abort the pregnancy by intramuscular injection of prostaglandin (PG). Serum samples were collected on Days 1, 7, 14, and 19 of the estrous cycle, at Days 0, 10, 20, 30, 40, 50, and 60 of pregnancy, and at Days 1, 3, 8, 10 over the period when abortion were occurring. Results of the present study indicated that during the estrous cycle the balance between Thl and Th2 cytokines slightly shifted toward Thl cytokine production (TNF-alpha and IL-2). The NO may have a direct positive role in inducing a Thl response. During early pregnancy, TNF-a and IL-2 serum concentrations markedly increased from Days 0 to 10, and gradually decreased from Days 10 to 60, while IL-10 and NO serum concentrations remained elevated from Days 0 to 60. The increased concentrations of IL-10 and decreased concentrations of TNF-alpha and IL-2 are characteristic of a Th2-enhanced response, which may be related to increased concentrations of NO. These changes may be essential to maintain a normal pregnancy. In addition, the serum concentrations of TNF-alpha, IL-2 and NO at Days 1,3, 8 and 10 of the period of induced abortion were markedly greater than that on Day 60 of pregnancy. Conversely, IL-10 concentrations at these four time points of abortion were markedly less than that on Day 60 of pregnancy. After abortion, the Th2 response shifted to a Thl-enhanced response. Thus, NO concentrations increase and the Thl-enhanced response may function synergistically to be involved in physiologic responses that lead to abortion of the pregnancy. It is concluded that the serum concentrations of the Thl/Th2 cytokine and NO changed temporally as the estrous cycle, pregnancy and abortion progressed advanced. A Th2-enhanced state promoted normal pregnancy, while increased concentrations of Th1 were observed during the period of fetal abortion. The concentrations of NO varied in regulation of the Thl/Th2 cytokine concentration balance during the three phases (estrous cycle, pregnancy, and fetal abortion) of goats. (C) 2016 Elsevier B.V. All rights reserved.