Comparative Study on the Expression Levels of Antithrombotic Genes in Five Sympatrically Distributed Leech Species

Medicinal leeches are rich in various antithrombotic components, holding significant pharmaceutical value. To investigate the differences in medicinal value 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 (anticoagulants, antiplatelet agents, thrombolytic agents, anti-inflammatory agents, and tissue penetration substances) showed that, except for W. laevis , the other four species exhibited the highest total expression in the anticoagulant functional 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. Based on our findings, we speculate that W. pigra , W. acranulata , and H. nipponia possess higher medicinal value, which, to a considerable extent, corroborates and aligns with the empirical accumulation of knowledge regarding the medicinal value of specific leech species in long-term traditional Chinese medicine practice.