A Study On The Mechanism Of Lactobacillus Rhamnosus Regulating The Pharmacokinetics Of CYP3A And P-gp Co-substrate By Using Cyp3a1/2 Knockout Rats

Cytochrome P450 3A(CYP3A)and P-glycoprotein(P-gp)are the most important drug metabolizing enzyme and drug transporter,respectively.Both of them are crucial components of the human intestinal barrier.Growing evidence demonstrates that the expression of CYP3 A and P-gp is regulated by gut microbiota.Modulating the function of CYP3 A and P-gp may result in toxicity and/or therapeutic failure.L.rhamnosus colonizes in the human intestinal tract normally.Recommended by doctors for intestinal health,it is one of the most concerned strains in the probiotic market.However,whether L.rhamnosus could influence the metabolism and transport of CYP3 A and P-gp cosubstrates remains unclear.This study investigated the potential and mechanism of regulating the verapamil pharmacokinetics by L.rhamnosus.We analyzed the regulation of L.rhamnosus on the expression of Cyp3 a and Mdr1a/1b in various metabolic and excretory organs of rats through RT-q PCR and WB experiments.And the activities of CYP1A2,CYP2B1,CYP2C11,CYP2D1,CYP2E1 and CYP3A1/2 were analyzed in vitro via microsome incubation assay.Results showed that L.rhamnosus significantly reduced exposure of verapamil in rats,and upregulated exposure of norverapamil,the main metabolite.It is found that L.rhamnosus treatment increased CYP3 A expression and activities in liver and small intestine.However,it did not affect the expression of P-gp in the liver,small intestine,and kidney,suggesting that L.rhamnosus may regulate the metabolism of verapamil through CYP3 A.Subsequently,using Cyp3a1/2 gene knock-out rats,we verified that L.rhamnosus reduced verapamil exposure in vivo due to upregulated CYP3 A activities in rats.In addition,the activities of CYP2B1,CYP2C11 and CYP2E1 in liver were significantly decreased after consuming L.rhamnosus,and the activities of CYP2B1 and CYP2D1 in small intestine were significantly upregulated.These variations of CYP enzymes activities might be related to alterations of gut microbiota composition after consuming L.rhamnosus.These findings suggested that L.rhamnosus decreased the exposure of verapamil by upregulating CYP3 A expression and activities.This study indicated that the gut microbiota can regulate the expression and activities of metabolic enzymes and then affect drug metabolism,which provides a new thinking for the regulation of drug metabolism and transport by gut microbiota.