The Changes And Significance Of TLR2, TLR4and MyD88in The Process Of Experimental Terminal Ileitis

Objective To investigate the changes and significance of TLR2, TLR4and MyD88in the process of experimental terminal ileitis.Methods60male SD rats were divided into three groups （model group, suture groupand control group） randomly and equally, hence, there were20rats in each group. Therats in model group were given side-to-side anastomisis. The terminal ileum tissues ofsuture group’s rats were sewed up by suture lines. And the rats of control group weregiven anesthesia. In the2^ndand8thweek after operation, took10rats from each groupand collected their terminal ileum tissues which were1-4cm away from the stitches（model group and suture group） or ileocecal valves. We observed the tissues withnaked eyes first and then imbedded them with paraffin to observe the pathologicalsections under microscope. The changes and expressions of TLR2, TLR4, MyD88andits mRNA were examined by Western Blot and RT-PCR. At last the changes of thethree molecules and their correlation were analyzed.Results1. Death rate of SD rats in each groupThere was no difference with statistical significance of death rate among each group（χ²=2.105,P=0.349）.2. The general state of each groupSituations as losing fur, listlessness, anorexia and losing weight happened during the3^rdto14^thdays of the postoperative period. The general state of rats turned better aftertaking food. Model group had slower recovery than the other two groups. What’smore, there were no statistically significant difference among three groups from the4^thto8thweek after operation （P>0.05）.3. Naked-eye observation and pathological changes of terminal ileum in each stage In the2^ndpostoperative week, tissues of model group and sture group showed acuteinflammation and their inflammatory scores were higher than control group’s underboth microscope and naked-eye observation.In the8^thpostoperative week, chronic inflammation occurred in model group. But forsuture group there was no evident infiltration of inflammatory cells and structuredamage. Hence inflammatory score of model group has risen in a larger degree thanthe other two groups.4. Expression level of TLR2, TRL4and MyD88of terminal ileum of rat_s in eachgroupIn both postoperative week2and8, the difference in expression level of three groupshad statistical significance.(TLR2: F^2W=177.3, P_2W=0.000; F^8W=594.1, P_8W=0.000);(TLR4: F^2W=1113.0, P_2W=0.000; F^8W=7496.0, P_8W=0.000);(MyD88: F^2W=156.1,P_2W=0.000; F^8W=994.7, P_8W=0.000). This showed marked increases of the threemolecules in model group. Compared with that in postoperative week2, expressionlevel of TLR2, TLR4and MyD88showed statistical significance in the8thweek afteroperation（TLR2: t_s=7.6223, P_s=0.0000; t_m=16.7251, P_m=0.0000）;（TLR4: t_s=11.0262,P_s=0.0000; t_m=76.7887, P_m=0.0000）;（MyD88: t_s=24.4459, P_s=0.0000; t_m=20.7673,P_m=0.0000）. Result showed evident increase rate of expressions of the threemolecules in the progress of CTI were158.88%,458.68%and233.87%respectively,and TLR4’s increase rate was the most evident.By analysis of variance at different time, we could see that there was statisticalsignificance for three molecules.(F^2W=26.0, P_2W=0.000; F^8W=294.5, P_8W=0.000).From the2^nd to the8th week after operation, increase rate of expression level ofTLR2, TLR4and MyD88were158.88%,458.68%and233.87%respectively. Andexpression level of increase rate of TLR4was the highest.5. Correlation among TLR2, TRL4and MyD88Experiment showed that in the progress of ETI, correlation among three moleculeswas positive, and in the8th week after operation, correlation coefficient among TLR2,TLR4and MyD88of model group was higher than that in the2^nd week. Conclusions1. In the progress of CTI, TLR2, TLR4and MyD88’s expression showed increasingexpression and was positively related to the degree of inflammation.2. Rise of expression levels of TLR4could be more obvious than that of both TLR2and MyD88, which might have indicated that Gram-negative bacteria could beconsidered as a initiating factor through the pathological progress of CTI.3. In the process of CTI, TRL2and TLR4played an essential role in the progress ofCTI by activating MyD88dependent signal pathway.