The Relationship Between The Reinfection Periapical Lesions By Enterococci Faecalis And Systemic Health: A Pilot Study

Periodontitis affect health in recent years has been paid more attention, andpeople gradually realize that oral diseases can affect the body health, and then theconcept of periodontal medicine has been put forward. It is not clear that whetherchronic periapical periodontitis, often been ignored by patients, can affect health.Since periodontitis and chronic periapical periodontitis have many similarities in thepathogenic process and mechanisms, so chronic periapical periodontitis and systemicdisease may have some correlations. Chronic periapical periodontitis may through away to cause bacteremia or lead cytokines into the blood and affect body health. Anda clinical study has found that chronic periapical periodontitis can affect the level ofcytokines in the peripheral blood, but whether it will cause a particular organ’spathological changes has not been reported.Refractory periapical periodontitis is a special type of chronic periapicalperiodontitis, it is defined as "refractory after repeated the normative root canaltreatment ", and Enterococcus faecalis is recognized as the one of the mainpathogenic bacteria of refractory periapical periodontitis. At the same time,Enterococcus is the common condition pathogenic bacteria in hospital infection. Itcan infect urinary tract, surgical wound, blood, and so on. In these conditions, theEnterococco can though blood circulation system caused bacteremia and the remoteorgan infection, or through cytokines affect the body health. So, the question is,whether Enterococcus faecalis, the pathogenic bacteria of refractory periapicalperiodontitis, can cause bacteremia or the remote organs infection?Considering the refractory periapical periodontitis’ pathogenic bacteria is singleand clear, and its condition is more complicated and difficult to control, and moreharmful, compared with chronic periapical periodontitis. Therefore we speculate that if chronic periapical periodontitis can affect the body health, so refractory periapicalperiodontitis may has deeper influence on body health. Another possibility, evenchronic periapical periodontitis, one of local inflammation, does not affect the bodyhealth, but it also can’t rule out the special one, refractory periapical periodontitiscaused by Enterococcus faecalis may affect the systemic health.So, on the base study of reinfection periapical periodontitis by Enterococcusfaecalis in the SD rats, comparative study the rat model of reinfection periapicalperiodontitis by Enterococcus faecalis, and periapical periodontitis model by residentoral mixed bacteria without Enterococcus faecalis, observing periapical biofilm bythe SEM, and testing related indicators in blood and some organs, including bacterialculture, cytokines ELISA test and histopathology test, to explore the relationshipbetween the chronic periapical periodontitis, specially reinfection periapicalperiodontitis by Enterococcus faecalis, and systemic health, and discusses thepathophysiological mechanism.Part I: The rat model of reinfection periapical periodontitis by Enterococcusfaecalis: observe the periapical biofilm by scanning electron microscopy(SEM)Methods: Set up the SD rat models of reinfection periapical periodontitis byEnterococcus faecalis on12rats. The periapical biofilm and the bacteria wereobserved on each time point, like chronic periapical periodontitis, after disinfection,1week or6weeks after channeling Enterococcus faecalis into root canals by scanningelectron microscopy (SEM).Results: Around the apical foramen of chronic periapical periodontitis tooth,observed island shaped narrow biofilm with mixed bacteria. After disinfection,biofilm could not be observed; only a few cocci adhere around the apical foramen. At1week after Channeling Enterococcus faecalis into root canal the cocci gathered,adhered and foramed small biofilm, the number of cocci was more than afterdisinfection. And at6weeks, a mass of cocci gathered and adhered, and continuous sheet mature biofilm around the apical foramed.Conclusion: In the rat model of chronic periapical periodontitis bacteria can plant andform the periapical biofilm. But the periapical biofilm of reinfection periapicalperiodontitis by Enterococcus faecalis is mature with dense construction.Part II: The rat model of reinfection periapical periodontitis by Enterococcusfaecalis: test Enterococcus faecalis in blood and some organs (heart,liver and spleen)Methods: Set up the SD rat models of reinfection periapical periodontitis byEnterococcus faecalis on15rats. The rats’ blood and some organs (heart, liver, spleen)were respectively collected on each time point, like6hours,12hours,24hours,48hours and96hours after channeling Enterococcus faecalis into the root canal, eachtime3rats by random. Then did the bacterial cultures, detected the16SrDNA ofbacteria by the polymerase chain reaction (PCR) and pyrophosphoric acid sequencing.Lastly compared the sequencing of culture bacteria with the standard strain(Enterococcus faecalis, ATCC29212), to check whether the Enterococcus facelisfrom the periapical periodontitis could infection the blood and organs.Results: Reinfection periapical periodontitis by Enterococcus faecalis could causetransient bacteremia only at6hours. At the same time found Enterococcus faecalis inthe liver and spleen, only at6hours and12hours; the heart could not foundEnterococcus faecalis.Conclusion: Reinfection periapical periodontitis by Enterococcus faecalis can causetransient bacteremia. At the same time Enterococcus faecalis can stay in the liver andspleen for a short time.Part III: The rat model of reinfection periapical periodontitis by Enterococcusfaecalis: test the cytokines of serumMethods: Set up the SD rat models of reinfection periapical periodontitis byEnterococcus faecalis (reinfection group), and primary periapical periodontitis SD ratmodel by resident oral mixed bacteria (chronic group) on39rats. The rat serum was respectively collected on each time point, like chronic groups: exposure for6weeks;after disinfection; reinfection group:6hours,12hours,24hours,48hours,96hours,1week,2weeks,3weeks,4weeks,5weeks and6weeks after channelingEnterococcus faecalis into root canal, each time3rats by random. Then did theELISA test, detecte CRP, IL-6and IL-2of rat serum.Results: All above the level of CRP, IL-6and IL-2had some similarities in variationtendency: the levels of cytokines begin decrease after disinfecting, and at the initialstage of channeling Enterococcus feacalis into root canal the tendency did not change,but during24～96h the levels turn rising to the highest, and then decreased again, andat5～6weeks turned rise slightly. The differences were the different time points tothe peak: the level of CRP at1w; the level of IL-6at2w; the level of IL-2at4w.Compared the level of these3inflammatory factors of the reinfection groups andchronic groups at6weeks, there were no significance difference.Conclusion: Reinfection periapical periodontitis by Enterococcus faecalis affect thelevel of the rat serum inflammation factors IL-2, IL-6and CRP.Part IV: The rat model of reinfection periapical periodontitis by Enterococcusfaecalis: histopathology test the rats’ some organs (aortic arch,myocardial, liver, spleen)Methods: Set up the SD rat models of reinfection periapical periodontitis byEnterococcus faecalis (reinfection group) and primary periapical periodontitis ones byresident oral bacteria (chronic group) on15rats. Respectively collected the rats’organs (aortic arch, myocardials, liver, spleen) on each time point, like chronic groups:exposure for3weeks, exposure for6weeks; after disinfection; reinfection group:1week,3weeks, and6weeks after channeling Enterococcus faecalis into root canal,each time3rats by random. Then did the Histopathologic slice and HE stain of theSD rats’ arcus aortae, myocardials, livers and spleens, to observe the histopathologicchanges.Results: observed the aortic arch, cardiac muscle, liver, and spleen of reinfectiongroup and chronic group. Both of them had been observed that the inflammatory cells edge seting and infiltrating on the aortic arch; observed the inflammatory cellsinfiltrating between the myocardial only at6w, but without obviously injury; observedthe edema of hepatic cell, disordered liver rope and necrosis; observed the infiltrationof inflammatory cell in spleen, without the obvious change. In the aortic arch andliver, the reinfection group’s inflammation change higher than the chronic group.Conclusion: Reinfection periapical periodontitis by Enterococcus faecalis andprimary periapical periodontitis both can cause the inflammatory change of the aorticarch, heart, liver and spleen, reinfection periapical periodontitis by Enterococcusfaecalis has more obvious change in the aortic arch and liver.