In VitroEffect of the Reproductive Hormones on the Oxidative Burst Activity of Polymorphonuclear Leucocytes from Cows: A Flow Cytometric Study

Abstract

In this study, the effect of reproductive hormones and substances with hormonal activity on the oxidative burst activity of blood polymorphonuclear leucocytes (PMN) high yielding dairy cows was evaluated. Different concentrations of: progesterone, oestradiol 17β, FSH, LH, GnRH, cortisol and PGF2α were incubated in vitro for 4 h with PMN of seven high milk yielding cows, during the period of anoestrous postpartum. Controls were run in parallel in which each hormone was replaced by its solvent. After incubation with hormones the competence of PMN to generate H(2) O(2) was monitored by flow cytometry. A down-regulation on the oxidative burst activity of PMA-stimulated PMN was observed when cells were incubated with progesterone. Significant (p ≤ 0.001) differences between control and progesterone incubated cells were observed from 6.56 μg/ml. The same predisposition was observed when PMNs were incubated with cortisol. Besides for all concentrations employed, a decrease in the burst activity was observed, only beyond 0.19 mg/ml, statistical differences between the results obtained by the control and the cortisol incubated cells were obtained. Concerning oestradiol 17β, an increase on H(2) O(2) -production was observed when PMN were incubated with 15 pg/ml and 45 pg/ml of this steroid (p ≤ 0.05), followed by a depression of the cell's activity when unphysiological concentrations were employed. Significant (p ≤ 0.05) differences between the obtained with the control and oestradiol 17β incubated cells were observed only in the highest concentration of oestradiol. No statistical differences were observed in the metabolic burst activity of PMN incubated with FSH, GnRH and LH when compared with the results obtained by the control.

Neuroprotective effects of progesterone in traumatic brain injury: blunted in vivo neutrophil activation at the blood-brain barrier

“…15 In bovine veterinary experiments, higher circulating PRO levels were correlated with reduced PMN respiratory (oxidative) burst and release of oxygen radicals. 16,17 In particular, PRO reduces lipid peroxidation in neuronal cells in a dose-dependent fashion, while increasing mitochondrial glutathione levels, a critical oxygen radical scavenger. 18 Lastly, PRO may blunt PMN adhesion receptor expression.…”

Latest update on predictive indicators, risk factors and ‘Omic’ technologies research of retained placenta in dairy cattle – A review

“…Both these factors have been finally proven to increase the predisposition to production diseases such as milk fever, endometritis, ketosis, displaced abomasum and retained placenta (Sordillo & Mavangira, 2014). In addition, some hormones like cortisol, progesterone, oestrogen and glucagon were reported to negatively affect the neutrophil´s function (Chaveiro & Moreira da Silva, 2010; Dervishi & Ametaj, 2017).…”