A mandibular propulsive appliance modulates collagen-binding integrins distribution in the young rat condylar cartilage.

We have previously shown that a mandibular propulsive appliance (MPA) stimulates cell proliferation and the synthesis of growth factors in the rat condylar cartilage. The aim of this study was to evaluate the effects of a MPA in the distribution of the integrin subunits alpha1 and alpha2 in this cartilage. Twenty eight days-old male Wistar rats were divided into treated (T) and age-matched control groups (C). Treated rats wore the appliance during 3, 5, 7, 9, 11, 15, 20, 30 and 35 days. The condyles were fixed, decalcified and paraffin-embedded. The distribution of alpha1 and alpha2 was studied by immunohistochemistry. Alpha1 distribution was uniform along the cartilage, increasing in 48 days-old rats (C20). Treated animals anticipated this increase to the age of 36 days (T9). The number of alpha2-positive cells was increased in C9 in the anterior condylar region, in C9 and C20 in the middle region and showed no differences in the posterior region. The MPA apparently abolished all variations, leading to a single increase at T30 in all regions. These results suggest that integrins containing the alpha1 and alpha2 subunits are modulated by forces promoted by the MPA, participating of the biological response to this therapy.