腹泻性贝毒对近江牡蛎P-糖蛋白和多药耐药相关蛋白表达的影响

Bivalves naturally exposed to toxic algae have mechanisms to prevent from harmful effects of diarrheic shellfish poisoning (DSP) toxins. However, quite few studies have examined the mechanisms associated, and the information currently available is still insufficient. Multixenobiotic resistance (MXR) is ubiquitous in aquatic invertebrates and plays an important role in defense against xenobiotics. MXR defense in mussels is mediated by at least two ABC transporter types including P-glycoprotein (P-gp) and multidrug resistance protein (MRP). Here, to explore the roles of P-gp and MRP in resistant mechanism of DSP toxins in shellfish, the accumulation of okadaic acid (OA), expression of P-gp and MRP in gills and digestive glands of Crassostrea rivularis were detected after exposure to Prorocentrum lima, a DSP toxins producing alga. Toxin content was detected by enzyme-linked immunosorbent assay; P-gp and MRP gene mRNA expression was analyzed using real-time quantitative PCR (qRT-PCR).The level of OA rapidly increased in gill tissues and digestive glands after exposure to P. lima. However, during the experiment, the C. rivularis grew well and none died, implying that C. rivularis have some tolerance to DSP toxins. The mRNA of P-gp and MRP increased in digestive glands after DSP toxins exposure, suggesting that P-gp and MRP might have an important role in the resistant mechanism of C. rivularis against DSP toxins. However, further studies should be addressed in the post-transcriptional mechanism of P-gp and MRP expression.