Distribution And Expression Of TLR2 And TLR4 In Human Urinary Tract And Their Changes After Endotoxin Invasion

Urinary tract infection (UTI) is one of the most common types of infection. Maskell has reported that about 50 perctent of women in the world have at least one time UTI in their lives. In USA, more than US$1.6 billion per year are spent in the management of UTI. A number of pathogen-related virulence factors have been identified that UTI relates mostly to pathogen adhesion to the epithelial lining of the urinary tract. In addition, patient-related factors determine the prevalence and severity of UTI. Diabetes, immuno-suppression, reflux and obstruction due to structural abnormalities of the urinary tract or pregnancy are known to predispose to UTI. Amongst the pathogens that cause UTI, and Gram-negative have been found to be the causative organism in～90% of cases.However, the pathogenesis of UTI is still unclear, especially about the mechanism of the bacteria recognition and signal conduction. Recent studies reveal that Toll-like receptors (TLRs) are the key molecules for recognizing microbial pathogen-associated molecular patterns (PAMPs) to evoke the inflammatory response. Several lines of evidence support the view that TLR2 is the receptor for Gram-positive bacterial peptidoglycan and lipoproteins and TLR4 is a critical component of the lipopolysaccharide(LPS) receptor complex, which forms a detection system for Gram-negative bacteria. Our studies focused on the distribution and expression of TLR2 and TLR4 in human urinary tract epithelium and discussed the change of their expression at the stimulation of endotoxin with RT-PCR method.The main results and conclusions were as follows:1. Primary the epithelium of human nephric tubule, pelvis, ureter and bladder were cultured in vitro successfully. The epithelium of nephric tubule was gained with Detrisac method and those of pelvis, ureter and bladder were done with tissue collagenase digestion and knife scrape method, which were simple and convenient and had a higher success rate.2. Keratins are the mark protein of the epithelium. We had identified the epithelium keratins with SABC method and found positive result in the experimental group and negative in the control group. 3.We found every epithelium expressed TLR2 and TLR4 with RT-PCR method, but their expression were different. The expression of TLR2 and 4 in nephric tubule group was significantly lower than other groups(P<0.05)4.With the stimulation of endotoxin, we found the expression of TLR4 was up- regulated obviously, while TLR2 was little. When the period of stimulation or the dose of endotoxin increased over some threshold, the expression was down-regulated, which related to the tolerance to endotoxin.