Abstract
This study was carried out in order to examine the effects of a low calcium environment on the histological appearance and incorporation of [35S] sulfate in the mandibular condyle of neo-natal rat mandible in organ culture.
The mandibulae of 1-day-old Wistar strain rats were cultured for 8 days in normal and low calcium culture medium (BGJb), the culture medium was changed every other day. The calcium concentration was 7.47±0.18 (n=10) mg/dl in the normal culture medium (control group) and 1.19±0.08 (n=10) mg/dl in low calcium (experimental group) . [35S] -sulfate (1 μCi/ml) was added to the culture medium at 6 days and the culture was incubated for a further 2 days to examine the incorporation of [35S] sulfate into mandibular condylar cartilage (M.C.C.) . After culturing, the histological appearance was examined. For the incorporation of [35S] sulfate into mandibular condylar cartilage, the mandibular condyle was homogenized and centrifuged, the precipitate was then dissolved with NCS tissue solubilizer and the radioactivity was measured.
The size of the mandibular condyle in the experimental group was greater than that in the control group. The mandibular condyle in experimental group showed a more roundish shape than that in the control group. The amount of chondroitin sulfate in M.C.C. increased in the experimental group more than that in control group. This increase in M.C.C. in the experimental group was not seen in heat-inactivated M.C.C.
From these facts, the size of mandibular condyle in a low calcium environment became larger in vitro, suggesting that one of factors of this phenomenon was due to the increase of chondroitin sulfate production by chondrocyte.
