Myodes rufocanus Cataract Identification and Transcriptome Analysis

Background: Cataract is a progressive lens opacity. According to the World Health Organization, about 45 million people in the world are blind, with about half of these cases attributable to cataracts. Due to the complexity of cataract disease, current research on cataracts is far from sufficient, so it is especially important to understand the development process and the pathogenic factors of cataracts. Myodes rufocanus (M. rufocanus) is an animal of the M. rufocanus of the hamster family Volinae. In developing M. rufocanus, we found an individual of M. rufocanus with a congenital cataract phenotype. We confirmed the symptoms of cataract under natural light and using a slit lamp. Methods: Therefore, we analyzed the mechanism of congenital cataract in M. rufocanus from the aspects of pathological histology, physiology and biochemistry, and gene level, aiming to explore the feasibility of its development into an animal model of cataract. Cataract is a progressive lens opacity and a leading cause of visual impairment. Understanding its pathogenesis requires appropriate animal models. In a laboratory-bred colony of M. rufocanus, we identified individuals with a spontaneous congenital cataract phenotype, confirmed by gross observation and slit lamp examination. To characterize this phenotype and explore its potential as an animal model, we performed pathological, physiological, biochemical, and transcriptomic analyses using three cataract-affected and three normal age-matched male individuals (8 weeks old per group). Results: Blood tests revealed significantly lower white blood cell and lymphocyte counts in the cataract group, while blood glucose and other biochemical parameters showed no significant differences. Histologically, cataractous lenses exhibited eosinophilic aggregation in the nuclear region with disorganized fiber cells. Transcriptome analysis identified 6544 differentially expressed genes, including downregulation of crystallin genes (CRYBB2, CRYBA4, CRYGS) known to be associated with congenital cataract. KEGG pathway enrichment analysis highlighted retinol metabolism, tyrosine metabolism, and cytochrome P450-related pathways. RT-qPCR confirmed reduced CRYBB2 expression in cataractous eyes. Conclusions: This study provides the first transcriptome dataset for M. rufocanus ocular tissues and offers preliminary evidence that this naturally occurring cataract phenotype may serve as a potential model for congenital cataract research.