[Effect of prostaglandin E1 on the rat mandibular condyle in organ culture].

The purpose of the present study was to investigate histologically and ultrastructurally the effect of prostaglandin E1 (PGE1) on the development and growth of the rat mandibular condyle in organ culture. The mandibular condyles of rats were divided into 5 groups (Groups 1-5) for light microscopy and 5 groups (Groups I-V) for electron microscopy. In Groups 1 and I, the mandibular condyles were removed from rats 1, 2, 4, 6 and 8 days after birth. In Groups 2 and II, 3 and III, 4 and IV, and 5 and V, the mandibular condyles were removed from rats immediately after birth and were cultured for 1, 2, 4, 6, and 8 days in the four media, namely BGJb, BGJb with 1% ethanol, BGJb with 0.5 micrograms of PGE1/ml, BGJb with 5 micrograms of PGE1/ml, respectively. The mandibular condyles of 5 groups (Groups 1-5) were examined histologically at 1 to 8 days, and the mandibular condyles of the other 5 groups (Groups I-V) were examined ultrastructurally at 4 and 6 days. 1. Light Microscopic Observation. i) Group 1 (in vivo) The zones of articular surface, proliferation, differentiation and hypertrophy of the mandibular condyle showed normal development. ii) Group 2 (BGJb) and Group 3 (BGJb+1% AL) The zones of proliferation and differentiation displayed a slight decrease in cell number compared with those of Group 1. iii) Group 4 (BGJb+0.5 micrograms PGE1) and Group 5 (BGJb+5 micrograms PGE1) The zone of proliferation showed a moderate decrease in cell number and in thickness compared with those of Groups 2 and 3. The zone of differentiation exhibited a marked decrease in cell number and in thickness, so that the level of the zone of hypertrophy moved upwards and close to the zone of proliferation. 2. Electron Microscopic Observation i) Group I (in vivo) The cells of the zones of articular surface, proliferation, differentiation and hypertrophy showed normal development in their cell organella such as mitochondria, rough surfaced endoplasmic reticulum and Golgi apparatus. ii) Group II (BGJb) and Group III (BGJb+1% AL) The cells of the zones of proliferation, differentiation and hypertrophy exhibited poor development in their cell organella compared with those of Group I. iii) Group IV (BGJb+0.5 micrograms PGE1) and Group V (BGJb+5 micrograms PGE1). The cells of the zone of proliferation exhibited poor development in their cell organella compared with those of Groups II and III. Furthermore, the zone of proliferation contained the fragments of cells in its intercellar areas.(ABSTRACT TRUNCATED AT 400 WORDS)