Melatonin as a Smart Protector of Pregnancy in Dairy Cows

Melatonin improves stroke through MDM2-mediated ubiquitination of ACSL4

The objective of this study is to investigate the impact of melatonin on ischemic brain injury and elucidate its underlying molecular mechanism. In this investigation, a mouse model of middle cerebral artery occlusion (MCAO) was established using the thread occlusion method, followed by treatment with two different doses of melatonin: 5 mg/kg and 10 mg/kg. Additionally, HT-22 cells were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) and treated with varying concentrations of melatonin. The findings demonstrated that melatonin significantly reduced the extent of cerebral ischemia, nerve damage, brain edema, and neuronal apoptosis in MCAO mice. In vitro experiments further revealed that melatonin effectively enhanced cell proliferation while reducing cell apoptosis and reactive oxygen species (ROS) production following OGD/R treatment. Mechanistic investigations unveiled that melatonin exerted its protective effect by inhibiting ferroptosis through modulation of MDM2-mediated ubiquitination of ACSL4. In summary, this study suggests that melatonin regulates the MDM2/ACSL4 pathway to safeguard against ischemic brain injury, thereby providing novel therapeutic targets for such conditions.

Melatonin administration during the first half of pregnancy improves the reproductive performance of rabbits: Emphasis on ovarian and placental functions

This study was designed to investigate the roles of melatonin administration during different sensitive windows of the first half of pregnancy in the function and gene expression of the ovary and placenta, hormone profile, and pregnancy outcomes in rabbits. Four equal experimental groups of 20 rabbits each were used. The first (FW), second (SW), and third (F + SW) groups comprised rabbits that orally received 0.7-mg melatonin/kg body weight during the first week, second weeks, and during both weeks of pregnancy; and the fourth group served as the control group (C). The total number of visible follicles significantly increased in all melatonin-treated groups compared with that in the C group. In all melatonin-treated groups, the number of absorbed fetuses was significantly reduced, whereas the weights of embryonic sacs and fetuses were higher than in the C group. The placenta efficiency was significantly increased in the F + SW group compared with that in the C group, followed by the SW group, whereas no significant difference in the placenta efficiency was found between the FW and C groups. Melatonin treatments significantly improved the expression of antioxidants, gonadotropin receptors, and cell cycle regulatory genes in the ovary, whereas only FW treatment upregulated steroidogenic acute regulatory gene. Compared with the C and FW groups, melatonin treatments during the SW and F + SW significantly upregulated the expression of most genes in the placenta. The concentrations of estradiol were significantly higher in the SW and F + SW groups than in the FW and C groups. The concentrations of progesterone were significantly increased in the FW group compared with those in the C and SW groups, whereas the F + SW group showed intermediate values. The litter size and weight at birth significantly increased in all melatonin-treated groups compared with those in the C group. The second week of pregnancy seems to be a sensitive window for melatonin actions during pregnancy. Thus, melatonin administration during the second week of pregnancy can be effective in improving pregnancy outcomes in rabbits.