[The role of bcl-2 and bax genes and programmed cell death in the temporomandibular joint development].
OBJECTIVE
To evaluate the roles of bcl-2, bax gene and programmed cell death(PCD) in the TMJ development.


METHODS
PCD, expression of both mRNA and protein of bcl-2 and expression of bax protein were observed by Tdt-mediated dUIP nick end labeling (TUNEL), mRNA in situ hybridization and immunohistochemical staining in TMJ of SD rats during series prenatal and postnatal developmental periods.


RESULTS
PCD was involved in condylar cartilage in development of different periods. The cells of PCD were mainly located in proliferative zone and the area between prehypertrophic zone and late hypertrophic zone. bcl-2mRNA was expressed with high levels in proliferative and prehypertrophic zones and very few matured chondrocytes expressed bcl-2. The expression of bcl-2 protein showed the same distribution as bcl-2mRNA, but gradually decreased in late hypertrophic zone, compared with strong expression of Bax throughout condylar cartilage.


CONCLUSIONS
PCD of condylar cartilage is regulated by bcl-2 and bax gene, the number and site of PCD are attributed to the change of bcl-2 and bax gene, and bcl-2 is an important gene in maintaining survival of chondrocytes during the proliferation, differentiation and maturation.
Li
S
S
Department of Oral Histology and Pathology, College of Stomatology, Fourth Military Medical University, Xi'an 710032, China.
Jin
Y
Y
Wang
H
H
D000818:Animals; D017209:Apoptosis; D015870:Gene Expression; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D020287:In Situ Nick-End Labeling; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013704:Temporomandibular Joint / Q000378:metabolism* / Q000473:pathology; D051028:bcl-2-Associated X Protein
C494828:Bax protein, rat; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D051028:bcl-2-Associated X Protein