Comparative study on the expression levels of antithrombotic genes in five sympatrically distributed leech species

Abstract Medicinal leeches are rich in various antithrombotic components, holding significant pharmaceutical value. To investigate the differences in potential antithrombotic capacity among species, this study utilized transcriptome sequencing technology to compare the expression differences of antithrombotic-related genes in five sympatrically distributed leech species (Whitmania pigra, Whitmania laevis, Whitmania acranulata, Hirudo nipponia, and Hirudo tianjinensis). The results revealed significant differences in the overall expression levels of antithrombotic genes among different species. Most samples clustered by species in the cluster analysis, indicating that the expression patterns of these genes are highly species-specific. Analysis of antithrombotic gene functional groups (coagulation inhibitor, platelet aggregation inhibitor, fibrinolysis enhancer, anti-inflammatory agents, and tissue penetration enhancer) showed that, except for W. laevis, the other four species exhibited the highest total expression in the coagulation inhibitor group. Among them, W. pigra, W. acranulata, and H. nipponia had a significantly greater number of dominantly expressed functional groups (N ≥ 2) compared to W. laevis and H. tianjinensis (N = 1). Gene family comparisons revealed that the number of dominantly expressed gene families in W. pigra, W. acranulata, and H. nipponia was significantly higher than that in W. laevis and H. tianjinensis. Additionally, 28 highly expressed key antithrombotic genes were identified across the five species, with the vast majority of these genes accounting for over 50% of the total expression within their respective gene families. According to the above results, we speculate that W. pigra, W. acranulata, and H. nipponia exhibit higher potential antithrombotic capacity at the transcriptional level. These molecular traits align, at least in part, with the empirical wisdom accumulated through centuries of traditional Chinese medicine practice regarding the therapeutic value of specific leech species, although further rigorous pharmacological validation is required to substantiate our hypothesis.