Maternal Dexamethasone Exposure Induces Sex-Specific Changes in Histomorphology and Redox Homeostasis of Rat Placenta

Effect of fish oil supplementation on histological changes, apoptosis and oxidative stress of rat placenta against formaldehyde-induced toxicity

Formaldehyde (FA) as a common organic compound has been shown to cause placental dysfunction and fetal defects. The potential benefits of fish oil (FOil) in protecting placental structures are attributed to its antioxidant properties. This study aimed to explore the preventive role of FOil in mitigating the adverse effects of FA in pregnant rats. Thirty pregnant Wistar rats were randomly categorized into five groups of control, sham (Normal saline; Orally and intraperitoneally), FOil (0.5 ml/day; Orally), FA (5 mg/kg/bw; intraperitoneally), FA+FOil. The treatment period was from day 0-20 of pregnancy. On the 20th day of pregnancy, placental morphometric parameters were measured. The histological and histochemical analyses were performed using H&E and PAS staining, respectively. Also, the placenta tissue was analyzed for oxidative stress biomarkers, p-53 protein levels, and the expression of caspase-3 gene. The administration of FA led to a significant decrease in the weight, diameter, and thickness of the placenta, as well as a decrease in the thickness of the decidua layer, junctional and labyrinth zone, and the number of trophoblast giant cells in rat placentas. FA led to a significant increase in placental p-53 protein levels, caspase-3 expression, and oxidative stress biomarkers. Administration of FOil to pregnant rats treated with FA led to a significant decrease in morphometric and histological changes, oxidative stress, and the expression of genes associated with apoptosis. The findings suggest that the administration of FOil to FA-treated pregnant rats can protect placental histopathological changes by enhancing the activity of the antioxidant enzymes.

DNA methylation-mediated 11βHSD2 downregulation drives the increases in angiotensin-converting enzyme and angiotensin II within preeclamptic placentas

Preeclampsia (PE) is a complex human-specific complication frequently associated with placental pathology. The local renin-angiotensin system (RAS) in the human placenta, which plays a crucial role in regulating placental function, has been extensively documented. Glucocorticoids (GCs) are a class of steroid hormones. PE cases often have abnormalities in GCs levels and placental GCs barrier. Despite extensive speculation, there is currently no robust evidence indicating that GCs regulate placental RAS. This study aims to investigate these potential relationships. Plasma and placental samples were collected from both normal and PE pregnancies. The levels of angiotensin-converting enzyme (ACE), angiotensin II (Ang II), cortisol, and 11β-hydroxysteroid dehydrogenases (11βHSD) were analyzed. In PE placentas, cortisol, ACE, and Ang II levels were elevated, while 11βHSD2 expression was reduced. Interestingly, a positive correlation was observed between ACE and cortisol levels in the placenta. A significant inverse correlation was found between the methylation statuses within the 11βHSD2 gene promoter and its expression, meanwhile, 11βHSD2 expression was negatively correlated with cortisol and ACE levels. In vitro experiments using placental trophoblast cells confirmed that active GCs can stimulate ACE transcription and expression through the GR pathway. Furthermore, 11βHSD2 knockdown could enhance this activating effect. An in vivo study using a rat model of intrauterine GCs overexposure during mid-to-late gestation suggested that excess GCs in utero lead to increased ACE and Ang II levels in the placenta. Collectively, this study provides the first evidence of the relationships between 11βHSD2 expression, GCs barrier, ACE, and Ang II levels in the placenta. It not only contributes to understanding the pathological features of the placental GCs barrier and RAS under PE conditions, also provides important information for revealing the pathological mechanism of PE.

Modulatory effects of quercetin on histological changes, biochemical and oxidative stress of rat placenta induced by inhalation exposure to crude oil vapor

The inhalation exposure to crude oil vapor (COV) has been shown to have adverse effects on the placenta and fetal development. The modulatory effects of quercetin (QUE) as a natural phenolic compound with antioxidant properties are promising for the protection of placental structure. This study aimed to investigate the modulatory role of QUE in mitigating histopathological damage, oxidative stress, and biochemical alteration in the placenta of COV-exposed pregnant rats. Forty-eight pregnant rats were divided into eight groups (days 15 and 20) as follows: 1-2) Control groups, 3-4) COV groups, 5-6) COV+QUE groups, and 7-8) QUE-treated groups (50 mg/kg). The inhalation method was used to expose pregnant rats to COV, and QUE was administered orally. On the 15th and 20th days of gestation, placental tissue was analyzed using PAS and H&E staining and immunohistochemistry. The expression of the caspase-3 gene and oxidative stress biomarkers including TAC, CAT, MDA, GPx, and SOD were investigated in the placental tissue. The COV significantly decreased the weight, diameter, and thickness of the placenta as well as the thickness of the junctional zone and labyrinth and the number of trophoblast giant cells in 15- and 20-day-old placentas (P<0.05). Also, COV significantly increased placental expression of caspase-3 and the oxidative stress biomarkers (P<0.05). The administration of QUE along with exposure to COV reduced morphometric and histological alteration, oxidative stress, and caspase-3 expression (P<0.05). Our findings indicated that QUE in COV-exposed pregnant rats can prevent placental histopathological alternations by increasing the activity of the antioxidant system.