Manganese(II) Chloride Alters Nucleotide and Nucleoside Catabolism in Zebrafish (Danio rerio) Adult Brain

Expression and Hormonal Regulation of Entpd3 at Various Estrous Cycle Stages in the Mouse Uterus

Ectonucleoside triphosphate diphosphohydrolase 3 (ENTPD3), a plasma membrane-bound metabolic enzyme, converts extracellular nucleotides into nucleosides. ENTPD3 is involved in various pathophysiological processes, including cellular adhesion, metabolism, activation, and migration. However, its specific function in the uterus remains unclear. This study aimed to investigate the expression pattern and localization of Entpd3 in the mouse uterus throughout the estrous cycle using immunohistochemistry (IHC), quantitative real-time PCR, and western blot analysis. The effect of sex steroid hormones on Entpd3 expression was also examined in ovariectomized (OVX) mice treated with 17β-estradiol (E2)/progesterone (P4) and estrogen receptor antagonist (Fulvestrant)/progesterone receptor antagonist (Mifepristone). Results demonstrated that elevated levels of Entpd3 mRNA and protein were noted during estrus and metestrus, with a decline in diestrus and proestrus. IHC revealed abundant ENTPD3 in the cytoplasm of glandular and luminal epithelial cells during estrus and metestrus. Additionally, treatment with E2 or P4 in OVX mice downregulated the expression of Entpd3 in the mouse uterus, which was rescued by Fulvestrant or Mifepristone. This study demonstrated that the expression of Entpd3 in the mouse uterus varied dynamically throughout the estrous cycle and was steroid-dependent, suggesting a potential role for Entpd3 in female mice's reproductive function.

Gallic acid modulates purine metabolism and oxidative stress induced by ethanol exposure in zebrafish brain

Gallic acid (GA) is a secondary metabolite found in plants. It has the ability to cross the blood-brain barrier and, through scavenging properties, has a protective effect in a brain insult model. Alcohol metabolism generates reactive oxygen species (ROS); thus, alcohol abuse has a deleterious effect on the brain. The zebrafish is a vertebrate often used for screening toxic substances and in acute ethanol exposure models. The aim of this study was to evaluate whether GA pretreatment (24 h) prevents the changes induced by acute ethanol exposure (1 h) in the purinergic signaling pathway in the zebrafish brain via degradation of extracellular nucleotides and oxidative stress. The nucleotide cascade promoted by the nucleoside triphosphate diphosphohydrolase (NTPDase) and 5'-nucleotidase was assessed by quantifying nucleotide metabolism. The effect of GA alone at 5 and 10 mg L^-1 did not change the nucleotide levels. Pretreatment with 10 mg L^-1 GA prevented an ethanol-induced increase in ATP and ADP levels. No significant difference was found between the AMP levels of the two pretreatment groups. Pretreatment with 10 mg L^-1 GA prevented ethanol-enhanced lipid peroxidation and dichlorodihydrofluorescein (DCFH) levels. The higher GA concentration was also shown to positively modulate against ethanol-induced effects on superoxide dismutase (SOD), but not on catalase (CAT). This study demonstrated that GA prevents the inhibitory effect of ethanol on NTPDase activity and oxidative stress parameters, thus consequently modulating nucleotide levels that may contribute to the possible protective effects induced by alcohol and purinergic signaling.

A Systematic Analysis of Metal and Metalloid Concentrations in Eight Zebrafish Recirculating Water Systems

Metals and metalloids are integral to biological processes and play key roles in physiology and metabolism. Nonetheless, overexposure to some metals or lack of others can lead to serious health consequences. In this study, eight zebrafish facilities collaborated to generate a multielement analysis of their centralized recirculating water systems. We report a first set of average concentrations for 46 elements detected in zebrafish facilities. Our results help to establish an initial baseline for trouble-shooting purposes, and in general for safe ranges of metal concentrations in recirculating water systems, supporting reproducible scientific research outcomes with zebrafish.