Biochemical and autoradiographical evidence that anterior mandibular displacement in the young growing rat does not stimulate cell proliferation or matrix formation at the mandibular condyle.
A removable bite plate was used to induce forward mandibular displacement in four-week-old rats for 10 h/day for 1, 3, 7, 11 and 14 days. The animals were killed and the condylar explants pulsed in vitro for 6 h with either [3H]-thymidine or [3H]-proline or 35SO(2-)4. The specific activity of radio-isotope incorporation was expressed as dis/min per microgram DNA, dis/min per mg protein and dis/min per microgram sulphated glycosaminoglycans (GAG). [3H]-thymidine autoradiography was also used in a 14-day experiment to establish a radioactive index (labelled cells per 1000 cells counted) for the anterior, middle and posterior regions of the condyle. There was no significant alteration in either cell proliferation (dis/min per microgram DNA and radioactive index) or matrix formation (dis/min per mg protein and dis/min per microgram GAG) at any point in the time scale.
Tewson
D H
DH
Department of Orthodontics, Eastman Dental Hospital, London, England, U.K.
Heath
J K
JK
Meikle
M C
MC
D000818:Animals; D001345:Autoradiography; D002455:Cell Division; D004247:DNA / Q000378:metabolism; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000254:growth & development*; D008335:Mandibular Condyle / Q000378:metabolism*; D011859:Radiography; D051381:Rats; D011919:Rats, Inbred Strains; D013936:Thymidine / Q000378:metabolism
D004247:DNA; D013936:Thymidine