Establishment and verification of rat experimental hyperalgesic pulpitis

GAO Lei; LI Hong-shi; YAN Lei; SUN Ya-nan; ZHANG Hai; WU Li-an

doi:10.15956/j.cnki.chin.j.conserv.dent.2015.05.008

Abstract：AIM:To establish and verify rat experimental hyperalgesic pulpitis.METHODS:36 male SD rats were randomly divided into 2 groups.The rats in control group (n=10)received no treatment after anesthesia,while the left maxillary first molar pulp of the rats in the pulpitis group (n=26)were exposed after anesthesia.6 rats of each group were randomly selected for face grooming test before and after 1,3,7 and 14 d of surgery respectively.The medul-la oblongatas and pulps of the remaining 4 rats in the control group were taken after 2 h of surgery.The remaining 20 rats in the pulpitis group were randomly divided into 5 groups (n=4),the pulps were taken after 1,3,7 and 14 d of surger-y respectively.HE staining,TNF-αand c-Fos immunofluorescence staining were conducted to measure the changes of pulp and bulbus medullae.RESULTS:The face Grooming after 1 d or 3 d of surgery in pulpitis groups were longer than that in the control group (P<0.05 ).In the pulpitis groups longest face grooming was observed 1 d followed by 3 d (P<0.05)after surgery.HE staining revealed that 1,3,7 and 14 d after surgery,inflammation and necrotic tissues ap-peared at the pulp horn,cervical-third,middle-third and apical-third of the root respectively.The mean optical density of TNF-αat various time points of pulpitis group were significantly higher than that of control group(P<0.05).In pul-pitis group highest TNF-αlevel was observed 1d followed by 3 and 7d after surgery(P<0.05),the lowest at 14d after surgery(P<0.05).c-Fos immunostaining results showed that c-Fos-positive cells were significantly increased in medul-lary dorsal horn after 2 h of pulp exposure.CONCLUON:Pulp exposure method can effectively establish rat experimen-tal hyperalgesic pulpitis madel,which simulates the process of clinical pulpitis and hyperalgesia.