目的：探讨咀嚼负荷对幼兔髁突软骨发育及软骨细胞中 BrdU 标记的影响。方法出生10 d 龄的32只幼兔，随机分为喂食固体硬饲料组和喂食粉末软饲料组。连续2周每天每只腹腔注射 BrdU （50 mg ／kg），在2、4、6、8周时每组处死4只幼兔，HE 观察组织形态学变化测量软硬组髁突厚度变化，免疫组化检测 BrdU 表达。结果髁突软骨前部厚度硬食组明显高于软食组，在中部无明显差异，髁突软骨后部厚度软食组高于硬食组。BrdU 免疫组化染色显示，发育期髁突软骨各层及软骨下骨骨髓腔内均有 BrdU 阳性标记，前部的增殖层表达最显著。第2周，硬食组在前、中、后3个部位的 BrdU 阳性率都高于软食组；第6周，软食组的中、后部位的阳性率高于硬食组；第 8周，软硬组均检测不到阳性细胞。结论软食组在低咀嚼力刺激下，幼兔髁突软骨细胞增殖启动较慢。适当的咀嚼压力能促进髁突软骨细胞的增殖，同时幼兔发育期的髁突生长还受到基因等内环境因素影响。%Objective To explore the effect of masticatory force on development of condylar cartilage and the BrdU labeling in grow-ing rabbits.Methods Thirty-two,10-day-old New Zealand white rabbits were divided into two groups randomly.One group received the normal hard diet and the other group received a powder soft diet.Both groups were injected intraperitoneally with bromodeoxyuridine (BrdU)50mg /kg for 2 consecutive weeks and then sacrificed at 2,4,6,8 weeks after the first BrdU injection.Presence of BrdU was de-tected using immunohistochemistry and morphological change was examined by HE staining.Results Compared with the soft-diet group,the thickness of anterior part of condylar cartilage in the hard-diet group increased significantly.There was no significant change in the thickness of intermediate part of condylar cartilage.The thickness of posterior part of condylar cartilage was thicker in the soft-diet group.Immunohistochemical analysis revealed staining of BrdU localized in the all cartilage zones and subchondral bone.BrdU-positive cells were abundantly detected in the proliferative zone.The BrdU labeling rate of hard-diet group in anterior intermediate and posterior part of condylar cartilage was higher than the soft-diet group significantly in the 2nd week.The BrdU labeling rate of soft-diet group in intermediate and posterior part of condylar cartilage was higher than the hard-diet group significantly in the 6th week.In 8th week BrdU-positive cells couldn′t be detected in both groups.Conclusions The growing rabbits with low masticatory force have a slow prolifera-tion initiation.It suggests that the proper masticatory force can promote the proliferation of cell in cartilage and the development of con-dylar is still affected by the internal factor such as gene.
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