Core Insights - Chinese scientists have made a groundbreaking discovery in regenerative medicine by identifying retinoic acid, a metabolite of vitamin A, as a key "molecular switch" that regulates the regenerative capacity of mammals [1][2] - The research marks a significant original innovation breakthrough in the field of regenerative medicine in China, particularly in understanding why mammals have limited organ regeneration capabilities compared to lower animals like salamanders [1] Group 1 - The research team focused on the ear structure of mammals, which evolved approximately 160 million years ago and consists of complex tissues such as skin, cartilage, and peripheral nerves [1] - Different mammals exhibit significant variations in their ear regeneration capabilities after damage, with species like rabbits and African spiny mice able to fully repair their ear structures, while mice and rats fail to regenerate effectively [1][2] Group 2 - A systematic comparative study was conducted on the ear damage repair processes in rabbits and mice, utilizing advanced techniques such as spatial transcriptomics and cell lineage tracing to analyze differences in cell types and gene expression during repair [2] - The study concluded that insufficient production of retinoic acid leads to regeneration failure, while external supplementation of retinoic acid can activate regeneration processes [2] - This research provides new insights into the key factors behind the failure of organ regeneration in mammals, including the heart and central nervous system, and has significant implications for understanding the regulation of regenerative capabilities in evolutionary biology [2]

Core Findings - Researchers from Kyoto University and Ritsumeikan University discovered that exposure to bisphenol A (BPA) and retinoic acid during early development significantly increases the risk of abnormalities in brain, nerve, and facial structure formation in zebrafish embryos [1][2] - BPA is commonly used in plastic production and is found in various consumer products, raising concerns about its impact on reproductive and endocrine health, as well as its potential link to conditions like infertility, cancers, allergies, obesity, and autism [1] - The study published in the journal Environmental Health Perspectives indicates that while BPA alone does not affect the expression of HOX genes, the presence of low concentrations of retinoic acid alongside BPA leads to a significant increase in HOX gene expression [1] Experimental Results - The zebrafish embryo experiments showed that simultaneous exposure to BPA and retinoic acid resulted in abnormal expression of hindbrain-related genes and increased probability and severity of abnormalities in craniofacial cartilage [2] - The hindbrain is a critical region in vertebrate embryos that will differentiate into structures such as the cerebellum and medulla [2] - The research team emphasized the need to pay special attention to the combined effects of plastic chemicals and other active substances on developmental health, as low concentrations of certain substances may not pose significant risks when isolated [2]