Effects of loading on chondrocyte hypoxia, HIF-1α and VEGF in the mandibular condylar cartilage of young rats.
Orthod Craniofac Res
; 21(1): 41-47, 2018 Feb.
Article
de En
| MEDLINE
| ID: mdl-29271061
ABSTRACT
OBJECTIVES:
To investigate hypoxia-inducible factor 1-alpha (HIF-1α) and vascular endothelial growth factor (VEGF) expression under altered loading, and to explore the relationship between loading and hypoxia in the mandibular condylar cartilage of young rats. SETTING AND SAMPLE POPULATION Eighty Sprague-Dawley rats. MATERIAL ANDMETHODS:
The reduced loading group was fed soft food, and their incisors were cut to avoid occlusal contact. The increased loading group was fed hard food and had forced jaw-opening. Ten rats from each group (n = 10) were sacrificed at 12, 24, 48, and 96 hours after initiation of the experiment. Pimonidazole hydrochloride (Hypoxyprobe-1, HP-1) was used as a hypoxia marker to confirm the hypoxic state. Hypoxic chondrocytes as indicated by HP-1, HIF-1α and VEGF protein expressions were recognized by immunohistochemical detection. HIF-1α and VEGF mRNA expressions were detected by semi-quantitative RT-PCR.RESULTS:
Hypoxyprobe-1 was confined in the upper layers of cartilage, and was most strongly expressed in the weight-bearing area of TMJ at 12 and 96 hours. Staining of HIF-1α and VEGF was most strongly expressed in the chondrocytes of the fibrous and proliferative layer at all time points. Furthermore, expressions were also displayed in the hypertrophic and calcified layers at 48 and 96 hours. The expressions of HIF-1α and VEGF mRNA were higher in the increased loading group than in the reduced loading group at 48 and 96 hours (P < . 05).CONCLUSION:
Mechanical loading seems to directly induce weight-bearing area hypoxia followed by new vessel formation, which indicates that these factors are related and important for the development of cartilage.Mots clés
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Chondrocytes
/
Facteur de croissance endothéliale vasculaire de type A
/
Cartilage élastique
/
Sous-unité alpha du facteur-1 induit par l'hypoxie
/
Condyle mandibulaire
Limites:
Animals
Langue:
En
Journal:
Orthod Craniofac Res
Sujet du journal:
ODONTOLOGIA
/
ORTODONTIA
Année:
2018
Type de document:
Article
Pays d'affiliation:
Finlande