Study Of The Effect Of The Low Dosage Endotoxin Damage On The Expression Of The Organic Cation Transporter (OCT1) MRNA In Hepatocytes

Objective: To elucidate the effect of the low dosage endotoxin damage on the expression of the organic cation transporter 1 (OCT1) mRNA in hepatocytes and make an approach to the probable effect of dexamethasone on the the expression of the OCT1 mRNA after endotoxin damage.Methods: (1) The endotoxin damage model was established in rats; (2) The change of the expression of OCT1 mRNA in hepatocytes after endotoxin damage was observed by in situ hybridization method; (3) The change of the ultrastructure of hepatocytes after endotoxin damage was observed with the electron microscope; (4) Dexamethasone was injected intraperitoneally before endotoxin damage in order to determine the influence of dexamethasone on the expression of OCT1 mRNA after endotoxin treatment.Results: (1) There was some damage in the ultrastructure of rat hepatocytes after low dosage endotoxin damage, which was more obvious at 8 hours and 16 hours after endotoxin treatment. But the damage in cell structure was not serious under microscope; (2) The expression of OCT1 mRNA decreased until 16 hours (0.5745±0.012, p<0.01)after endotoxin treatment and then increased after this time point, which is still lower than the normal control; (3) The expression of OCT1 mRNA in rat hepatocytes increased at each time point after endotoxin damage with dexamethasone treatment. It was highest at 16 hours(0.6327±0.007, p<0.01) after endotoxin damage, but it was still lower than that of the normal control. (4) There was not remarkabledifference among the levels of endotoxin in the rats after low dosage endotoxin damage at each time point.Conclusion: (1) Endotoxin could repress the expression of OCT1 mRNA even before the low dosage endotoxin did serious damage to the structure of hypatocytes; (2) Dexamethasone could not induce the expression of OCT1 mRNA in normal hepatocytes, but could lighten the repression of endotoxin on the expression of OCT1 mRNA. And then the expression of OCT1 mRNA could increase at some extent after endotoxin damage with dexamethasone treatment; (3) Dexamethasone could increase the biliary flow by inducing the expression of OCT1 mRNA after endotoxin damage.