[A histological innovative study of Balb/c mouse tooth germ transplanted to nude mouse in vivo].
OBJECTIVE
To observed the changes of the developed mouse's dental germs after transplanting into nude mouse and find some theoretical foundation for establishing an innovative experimental model.


METHODS
Eight tooth germs from four 5th day postnatal Balb/c mice were transplanted to the back muscles of the adult nude mice. At seventh and fourteenth day after grafting, the germs were collected, fixed, demineralized, dehydrated, and embedded in wax. Serial sections of 5 microm thick were made following the routine methods, stained with haematoxylin-eosin dying solution, and observed under a light microscope. The mandibular first molars were taken out from the 12th and 19th day postnatal mouse. Serial sections of 5 microm thick were made following the routine methods, then compared with the germs after graft.


RESULTS
All implantations were located in the superficial muscles with abundant capillary vessels. The dental germs could further developed after grafting under the microscope, but slower than dental germs self-development. The layer of dentin was thin, plenty of dentin with disorganized dentin tubule formed after grafting. Although the location of Hertwig's epithelial root sheath hardly moved, the roots developed further. The floor of pulp chamber could form and the pulp chambers were shrinking. The degree of calcification in the area of root increased very clearly. The inflammatory reaction was found at 7th day while hardly noted at 14th day after grafting.


CONCLUSIONS
It suggests that late development of mouse tooth germs could further develop after heterotopic transplantation within the superficial muscles of the nude mouse. This model is useful for study of tooth root development in short time.
Xie
Rui-yue
RY
Department of Periodontology, School of Stomatology, Shandong University, Jinan 250012, Shandong Province, China.
Yang
Pi-shan
PS
Li
Shu
S
D000818:Animals; D000831:Animals, Newborn; D003804:Dentin; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008963:Molar; D009805:Odontogenesis; D009924:Organ Culture Techniques; D064171:Superficial Back Muscles; D014070:Tooth; D014083:Tooth Germ / Q000033:anatomy & histology* / Q000254:growth & development / Q000637:transplantation*; D014092:Tooth Root / Q000254:growth & development*