Joint Cartilage Cell Apoptosis And Proliferation In The Base Of Skull Development In Rats

Part 1Observation and measurement of histological characteristics of the synchondrosis growth plate during cranial base development in ratObjective To observe and measure the histological characteristics of the synchondrosis growth plate in different stages during cranial base development in rat.Methods SPF grade SD male rats were divided into seven group(4d,8d,16d,32d,48d,64d,128d).Synchondroses Sections(intersphenoidal synchondrosis(iss)and spheno-occipital synchondrosis(sos))were stained with hematoxylin and eosin for observation of cellular modality.Histology and morphometry were used.Results The synchondrosis could be divided into four zones of cell:central zone, proliferative zone,hypertrophic zone,erosive zone.The cell of each zone had theirown feature.Along with an increase in the age of rat,the width of the synchondrosis generally is reduces.In the early time during growth,from 4d to 16d, the thickness of central zone and proliferative zone were much wide.In the later,from 32d to 128d,proliferative zone was degenerated,and hypertrophic zone was growing flourishly and play an important part in development.Sos was later than iso in the change of synchondrosis.Conclusion The transition time of the rat synchondrosis growth:from the swift growth to rebuild the transition primarily is possibly in 32d-48d.The duration of the sos's growth is longer than iso,while the fusion time of the sos's growth is later than iso. Part 2Apoptosis and proliferation in the synchondrosis growth plate during cranial base development in ratObjective To study Apoptosis and proliferation in the synchondrosis growth plate during cranial base development in rats,and to find the rule of the cranial base development.Methods SPF grade SD male rats were divided into seven group(4d,8d,16d,32d,48d,64d,128d).Synchondroses Sections(intersphenoidal synchondrosis(iss) and spheno-occipital synchondrosis(sos))were studied by dTdT mediated dUTP nick end labeling(TUNEL)and immunohistochemical S-ABC method.Results Many PCNA positive chondrocytes were found in Synchondroses of 4d,8d,16d,while less PCNApositive cells in 32d,48d,64d,128d.There was no TUNEL positive chondrocytes in 4d,8d,but a few TUNEL positive cells were found in 16d. And there were more positive cell in the 32d,48d,64d.In 128d the result was negative.Conclusion Apoptosis and proliferation participate in the development of the cranial base.And they are consistent with the change of proliferative zone and hypertrophic zone.The degree of the apoptosis plays an important part of the difference between two synchondrosis. Part 3The investigation on the Signal Transduction Pathways of Apoptosis during cranial base development in ratObjective to study and research the signal transduction pathways of apoptosis during cranial base development in rat,and and the effect of iNOS,Fas,Caspase-8,9 expression in this process.Methods SPF grade SD male rats were divided into seven group(4d,8d,16d,32d,48d,64d,128d).Synchondroses Sections(intersphenoidal synchondrosis(iss) and spheno-occipital synchondrosis(sos))were studied by immunohistochemical S-ABC method to detected correlation factors in apopotosis——iNOS,Fas, Caspase-8,9.And the relationship with them were discussed.Results iNOS,Caspase-9 were express in Central zone and proliferative zone on 4d,8d,16d,while Fas,Caspase-8 were express in hypertrophic zone,erosive zone on4d,8d,16d.Conclusion There were two pathways in the synchondrosis during the development of cranial base.Fas pathway display a leading role,while mitochondrion pathway were only in central zone and proliferative zone primarily.