Effects of rhodamine B on neuronal behavior and physiological function in the F1 generation of Danio rerio

Rhodamine B (RhB) is a basic dye that has been used in various applications, including drugs, food, beverages, and cosmetics, since the mid-twentieth century. Environmental exposure to RhB can threaten human health, particularly affecting physical and neurological development. Given its widespread use, concerns persist regarding its impact on pregnant women and future generations (F1). This study investigated the effects of RhB exposure in adult female zebrafish (D. rerio), using concentrations of 0.25, 0.5, and 1.0 μM. The analysis of biochemical, neurochemical, mRNA expression, and behavioral performance in the F1 generation was assessed. Our results indicated that exposure to RhB caused hatching problems, teratogenic effects, and cardiac and neuronal developmental malformations in offspring. Behavioral results, such as locomotor, swimming, social preference, aggression, and sensitization, were performed on the F1 generation. At 1.0 μM, RhB treatment significantly decreased locomotion, anxiety-related behavior, shoaling, mirror interaction, and exploratory behavior (p < 0.05), exhibiting dose- and time-dependent effects relative to controls. At 0.25 μM, exposure influenced the antioxidant (at 1.0 μM), and levels of serotonin, dopamine, and acetylcholinesterase were significantly affected, whereas the activities of Ca²⁺-ATPase, Na⁺/K⁺-ATPase, Mg²⁺-ATPase, and 5' nucleosidase were significantly reduced. The brain mRNA variations of neuronal development (btg2, npas4a, ier2a, vgf, and egr1) were significantly effects at 1.0 μM (p < 0.05); myocardial cell maturation (hspb, tcap, myoz3a, flnca, bag3, tnnt2c, actc2, desma, mybpc2b, and hspb8) and oxygen transportation and hypoxia (hif1al, hbbe1.3, alas2, hbbe1.1, hbae3, igfbp1a, and hbbe2) were significantly affected on exposure to RhB in the F1 generation when compared to control. The RhB exposure causes transgenerational disruptions in zebrafish, including morphological abnormalities, abnormal mRNA expression, neurochemical imbalances, and biochemical disruptions, leading to autism-like behaviour phenotype in the F1 generation of zebrafish..