Combined Inhibition of Thrombosis by Lactobacillus paracasei and Clopidogrel.

BACKGROUND: Lactobacillus paracasei (LP) may affect the efficacy of clopidogrel (CLP). METHODS:  Forty Sprague-Dawley (SD) rats were randomly divided into control group, LP group, CLP group, LP (pretreatment) + CLP group, and CLP + LP(posttreatment) group (n=6-8). The administration doses of CLP and LP in rats were 6.75 mg/kg/d and 10(9) CFU/d, respectively, for 14 consecutive days. Tail vein blood was collected to detect blood drug concentration, platelet function. Then, a thrombosis model was constructed using 20% FeCl₃, the complete vascular occlusion time, thrombus weight, and thrombus inhibition rate, inflammatory factors, gut microbiota, short-chain fatty acids (SCFAs), trimethylamine N-oxide (TMAO) and mucosal barrier were evaluated. RESULTS:  Compared with the CLP group, the blood concentrations of AM and CA in the combined group were significantly decreased, while platelet aggregation (MPA) and platelet reaction index (PRI) were significantly increased. After model construction, the thrombosis formation time was significantly prolonged, the thrombus weight was significantly reduced, and the thrombus inhibition rate was significantly; the secretions of TNF-α, IL-1β, P-selectin, GPIIb/IIIa, and D-dimer were significantly decreased in the combined group. The structure of gut microbiota also changed significantly after CLP treatment, and LP combined with CLP could improve the dysbiosis caused by CLP through increasing SCFAs and decreasing TMAO. In addition, the expressions of ZO-1, Occludin, and P-gp were increased in the combined groups. It should be noted that there is a directional discrepancy between the changes in platelet function indices (MPA and PRI) and in vivo thrombosis outcomes, which may be related to the multi-factorial regulation of in vivo thrombosis. CONCLUSION: LP may regulate the structure of gut microbiota (increasing SCFA-producing bacteria and inhibiting TMAO-producing bacteria), thereby protecting the intestinal mucosal barrier, inhibiting inflammatory responses, and cooperatively acting with CLP to inhibit platelet activation and improve coagulation function, although the specific mechanism needs further verification.