1.VGCC expression in facial nucleus motoneurons after facial nerve injury in adult rats
Lili CAO ; Rongcheng HU ; Zhenggen PIAO
Journal of Practical Stomatology 2017;33(2):162-167
Objective:To investigate the expression change of voltage-gated calcium channels(VGCC) in the facial nucleus motoneurons of adult rats after facial nerve injury.Methods:The facial motor nucleus was localized by retrograde labeling with a fluorescent dye,Dil,and identified by Nissl staining.The facial nerve injury model was established by amputation of the main trunk of left facial nerve.Exposure of the right facial nerve without nerve transection was used as the control.Rats were sacrificed at 3,7,14 and 28 days after injury respectively(n =10),the brainstem containing facial nucleus were collected,the expression of P/Q,N,L,R-type calcium channel α1A,α1B,α1C and α1E subunits was examined by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR).Results:Immunohistochemistry results show that whereas α1A,α1E subunits levels did not vary compared with control group 3,7,14,28 days after injury(P >0.05),α1B and α1C subunits immunoreactivity decreased in the motoneurons after injury,a sharp decrease was detected at 14 days after injury(P < 0.01),thereafter returned to the control level at 28 days after axotomy(P >0.05).The expression of α1B and α1C mRNA was down-regulated,especially 14 days after the injury(P <0.01),and then recovered to normal level at 28 days (P > 0.05).In addition,there was no significant difference of α1A and α1E subunits and their correspoding mRNA between operated group and control group at all time points(P > 0.05).Conclusion:VGCC is involved in facial nerve injury and down-regulation of N-type and L-type calcium channels may be one of the role.
2.Comparative development of mouse tooth germs transplanted in subrenal capsule and oral submucosa
Ying HE ; Pengfei LIU ; Xiao LIU ; Zhenggen PIAO ; Jinglei CAI
Chinese Journal of Pathophysiology 2015;(1):141-147
AIM:To compare 2 environments , the subrenal capsule and oral submucosa , for producing well-formed teeth from mouse tooth germs and for exploring the ideal environment for tooth regeneration .METHODS: Two groups were set up .Group A was transplanted with the mouse embronic day ( ED) 14.5 first mandibular molar tooth germs into the subrenal capsule , while group B was transplanted with the ED 14.5 first mandibular molar tooth germs into the oral submucosa.After 3 weeks and 4 weeks, the host mice were sacrificed, and the transplanted explants were evaluated with morphologic observation , histological structures , hardness and elastictic modulus tests , and chemical compositions .RE-SULTS:(1) The explants isolated from both environments showed the tooth-like structures, but as to the group B, the crown was smaller, and the shape of the cusps was not significant .(2) HE staining showed that the dentin and enamel in group A were thicker than those in group B in which the ameloblasts and odontoblasts were differentiated not very well .(3) In the test of enamel hardness , only the hardness of 4 weeks in group B was lower than normal mouse tooth .In the test of enamel modulus , the elastic modulus of enamel in 3 weeks of group A was slightly lower than normal mouse tooth , but the difference was not significant .The elastic modulus of enamel in 4 weeks of group A and group B was significantly lower than normal mouse tooth and 3 weeks of group B .The hardness and elastic modulus of dentin in 3 groups was not significant . (4) Raman spectroscopy showed 2 groups grew in harmony in general , they all had the largest peak in the point of 961 cm-1 , but the 3 weeks of group B had an obvious peak in the point of 2 947 cm-1 .CONCLUSION:For the development of ED14.5 tooth germs, we obtain almost the whole tooth in subrenal capsule transplantation after 3 or 4 weeks.The buccal submucosa environment still has a certain influence on the tooth germ development , although there are some differences about the tooth development between this environment and subrenal capsule environment .
3. Root canal anatomy of maxillary second premolars at various ages observed by cone-beam CT
Rongcheng HU ; Wei XIE ; Yaqun HU ; Zhenggen PIAO
Chinese Journal of Stomatology 2019;54(11):733-738
Objective:
To observe the morphological changes of root canals in maxillary second premolars at various ages by using cone-beam CT (CBCT) in order to provide imaging and theoretical reference for clinical treatments.
Methods:
The digital CBCT data of the maxillary second premolars in 440 cases from the patients in Department of Stomatology, The First Affiliated Hospital, Jinan University during March 2011 and December 2017 were collected. The CBCT images were divided into 4 groups according to the patients′ ages: groups ≤20, 21-40, 41-60 and>60 years old, respectively. Changes of morphologies of root canals with aging including such parameters as types of the root canal, incidence of double root canals in single rooted teeth, distance between both root canal orifices of double rooted canals, and morphological change of the cross section of roots.