The effects of sex hormone on growth plate chondrocyte.

性激素在骺生长板软骨细胞增殖、成熟和死亡的调控中起重要作用。我们研究了雄性去势对软骨细胞的细胞动力学的影响，通过增殖和死亡细胞的数量来定义。取10、15、20和25周龄正常和8周龄去势兔的生长板。使用caspase-3和PCNA的免疫染色对它们进行凋亡和增殖软骨细胞的染色。去势组caspase-3阳性率高于正常组，PCNA阳性率低于正常组。此外，去势兔软骨细胞的数量明显少于同龄正常兔。本研究提示去势可导致生长板软骨细胞凋亡增加，增殖能力下降。本研究通过体外培养软骨细胞，观察性激素对软骨细胞的影响。取17日龄鸡胸骨，H-E染色显示，胸骨头侧1/4处为肥大软骨细胞，尾侧1/2处为未成熟软骨细胞。取胸骨头侧5 mm、尾侧8 mm，按Gerstenfeld法培养。提取培养软骨细胞的RNA，进行逆转录-聚合酶链反应（RT-PCR）。头侧软骨细胞呈10型胶原，尾侧软骨细胞呈2型胶原。说明前者为成熟肥大软骨细胞，后者为未成熟软骨细胞。用培养系统进行性激素负荷试验。在肥大和早熟软骨细胞中加入10- 10、10 - 9、10 - 8、10 - 7、10 - 6 mol/l的睾酮和雌激素。检测ALP活性、细胞增殖活性、细胞死亡率、2型胶原和10型胶原mRNA表达。睾酮刺激细胞增殖，雌激素刺激细胞死亡。

Sex hormones play important roles in the regulation of chondrocyte proliferation, maturation and death in epiphyseal growth plate. We investigated the effects of male castration on the cell kinetics of chondrocytes, defined by the numbers of proliferating and dying cells. The growth plates of normal rabbits and castrated at 8 weeks of age were obtained at 10, 15, 20 and 25 weeks old. They were stained for apoptotic and proliferating chondrocytes using immunostaining for caspase-3 and PCNA. The castrated rabbits showed higher caspase-3-positive and lower PCNA-positive ratios than the corresponding normal groups. In addition, the number of chondrocytes in the castrated rabbits was less than that of the normal ones at the same age. Our study suggested that castration led an increase of apoptosis and decrease of proliferating ability in growth plate chondrocytes.Then, we cultured chondrocytes to investigate the effects of sex hormone on chondrocytes in vitro. 17-day-old fatal chick sterno was obtained and revealed by H-E stain to be composed of hypertrophic chondrocytes in 1/4 of cranial side and premature chondrocytes in 1/2 of caudal side. We obtained 5mm cranial and 8mm caudal side of sterno and cultivate them according to Gerstenfeld's method. The RNA of the cultured chondrocytes was extracted and reversetranscription-polymerase chain reaction (RT-PCR) was performed. The cranial chondrocytes presented type 10 collagen and the caudal ones type 2 collagen. That indicated that the former is mature hypertrophic chondrocyte and the latter premature chondrocyte. Sex hormone load test was performed with the culture system. Testosterone and estrogen at 10-10,10-9,10-8,10-7,10-6mol/l were added in hypertrophic and premature chondrocyte. The ALP activity, proliferative activity, cell death, mRNA of type 2 and 10 collage were tested. Testosterone stimulated cell proliferation, and estrogen stimulated cell death.