Phthalates are commonly used in plastic products in daily life. The endocrine-disrupting effects of phthalates have been widely reported. Accumulating evidence from human cohorts and lab animals indicate exposure to phthalates might impair neurodevelopment. However, the direct causal relationship and mechanism between phthalates with neurodevelopment and neurotoxicity have not been firmly established. We found that phthalates (i.e. DBP, DINP, BBP) disrupted the expression of estrogen receptors (esr1, esr2a, esr2b), and impaired neurogenesis in the brain of zebrafish during embryonic development. Moreover, the abnormal expression of estrogen receptors, especially esr2a, was partly rescued in zebrafish which exposed to phthalates, with the estrogen receptor antagonist tamoxifen. Hence, impaired neurogenesis of zebrafish exposed to phthalates was partly reversed by tamoxifen treatment. Moreover, our results show that induced pluripotent stem cells (iPSC)-derived human neurons exposed to phthalates triggered double-strand DNA breaks in vitro. Overall, this study demonstrates that exposure to phthalates affects neurodevelopment in zebrafish embryos and induces neurotoxicity in human neurons partly through disrupting the expression of estrogen receptors.

The Organization for Economic Co-operation and Development (OECD）Test Guideline (TG) 236 for zebrafish embryo acute toxicity testing was adopted for chemical toxicity assessment in 2013. Due to the increasing demand for prediction and evaluation of the acute toxicity using zebrafish embryos, we developed a method based on OECD 236 test guideline with the aim to improve the testing efficiency. We used 4–128 cell stage zebrafish embryos and performed an exposure assay in a 96-well microtiter plate, observing the lethality endpoints of embryos at 48-h postexposure. A total of 32 chemicals (two batches) were used in the comparison study. Our results indicated that the logarithmic LC₅₀ (half lethal concentration) obtained by the modified method exhibited good correlation with that obtained by the OECD 236 testing method, and the R² of the linear regression analysis was 0.9717 (0.9621 and 0.9936 for the two batches, respectively). Additionally, the intra- and inter-laboratory coefficient of variation (CVs) for the LC₅₀ from the testing chemicals (17 chemicals in second batch) was less than 30%, except for CuSO₄. Therefore, the developed method was less time-consuming and demonstrated a higher throughput for toxicity testing compared to the prior method. We argue the developed method could be used as an additional choice for high-throughput zebrafish embryo acute toxicity test.

Rehmanniae Radix Praeparata (RRP), a staple in traditional Chinese medicine, is derived from Rehmannia glutinosa Libosch and is renowned for its wound-healing properties. Despite its clinical prevalence, the molecular mechanisms underlying RRP's wound-healing effects have not been fully elucidated. This research endeavored to delineate the molecular and cellular mechanisms underlying the beneficial effects of RRP on wound healing, utilizing a zebrafish model. Zebrafish larvae at 3 days post-fertilization were amputated at the fin and subsequently treated with RRP. The pro-wound healing and regenerative effects of RRP were evaluated through morphological analysis, assessment of cell proliferation and apoptosis, Additionally, mechanistic insights were gained through a comprehensive approach encompassing network pharmacology analysis, cell tracing, RNA-sequencing, CRISPR/Cas9 gene editing, and pharmacological inhibition. Our findings demonstrate that RRP significantly accelerates caudal fin regeneration in zebrafish following injury by suppressing cell apoptosis, promoting cell proliferation, and upregulating the expression of regenerative-related genes. Furthermore, RRP triggers autophagy signals during the regenerative process, which is attenuated by the autophagy inhibitor chloroquine (CQ). Notably, the administration of RRP enhances the expression of ahr1 and ahr2 in the regenerating fin. Genetic knockout of ahr1a, ahr1b, or ahr2 using CRISPR/Cas9, or pharmacological blockade of AHR signals with the antagonist CH-223191, diminishes the regenerative potential of RRP. Remarkably, zebrafish lacking ahr2 completely lose their fin regeneration ability. Additionally, inhibition of AHR signaling suppresses autophagy signaling during fin regeneration. This study uncovers that RRP stimulates fin regeneration in zebrafish by inducing AHR signals and, at least partially, activating the autophagy process. These findings provide novel insights into the molecular mechanisms underlying the wound-healing effects of RRP and may pave the way for the development of novel therapeutic strategies.

Background: Microencapsulation of hydroxypinacolone retinoate (HPR) can improve its application in cosmetics. Objective: To investigate the safety and efficacy of Spherulites Paeony Superior Retinol, a HPR microcapsule containing 5%–10% peony seed oil, 0.01%–1% epigallocatechin gallatyl glucoside (ECGG), and 0.1%–1% HPR. Methods: The safety of Spherulites Paenoy Superior Retinol was evaluated with zebrafish embryo self‐rotation irritation test and developmental toxicity test. SymRenew™ HPR was used as a reference. The skin care efficacies of Spherulites Paenoy Superior Retinol were evaluated using zebrafish embryos covering antioxidation, anti‐inflammation, blood circulation, whitening, wound healing, skin barrier protection, Type I collagen, elastin, and 5α‐reductase genes expression activities. Results: The irritation test revealed that 250 μg/mL Spherulites Paenoy Superior Retinol did not, while 20 μg/mL SymRenew™ HPR significantly ( p < 0.05) increased zebrafish embryo self‐rotation frequency. The developmental toxicity test found the teratogenicity index (half lethal concentration/half toxicity concentration) of Spherulites Paenoy Superior Retinol and SymRenew™ HPR were 1.9 and 3.1, respectively. The efficacy analysis results showed that 5 μg/mL Spherulites Paenoy Superior Retinol significantly ( p < 0.05) exerted 7.1% anti‐ROS, 20% anti‐inflammation, 14% enhanced blood circulation, 10% suppressed melanin synthesis, 9% enhanced tail fin regeneration, 72% elicited skin barrier protection activity, enhanced the expression of Type I collagen genes col1a1 , col1a2, and col1a2 by 34%, 51%, and 42%, respectively, and elastin gene elna by 46%, and suppressed the expression of 5α‐reductase genes srd5a1, srd5a2a, and srd5a2b by 52%, 15%, and 30%, respectively. Conclusion: This study demonstrated that Spherulites Paenoy Superior Retinol is a safe cosmetic ingredient with multi‐skin care efficacies.