兔原发性甲状旁腺机能亢进甲状旁腺细胞增生与凋亡的相关性

Relationship between proliferation and apoptosis of parathyroid cell in rabbits with primary hyperparathyroidism

目的探讨兔甲状旁腺细胞增殖与凋亡在原发性甲状旁腺机能亢进症（PHPT）发病机制中的作用。方法健康成年中国白兔80只，随机分成两组，对照组40只以正常饮食（Ca：P，1：0．7）喂养，实验组40只以高磷饮食（Ca：P，1：7）喂养诱发原发性甲状旁腺机能亢进动物模型。在第3、4、5、6个月动物死亡后，分别对实验组和对照组动物行甲状旁腺细胞计数，同时采用免疫组织化学法观察腺体增殖细胞核抗原（PCNA）和Bcl-2的表达及采用DNA片段末端标记作细胞凋亡的定量检测，并与对照组正常腺体作对照研究。结果PHPT组腺体细胞计数（个／高倍视野）是正常对照组的1．61倍（分别为673±151与4184-25，t=-12．112，P〈0．01）；PHPT组凋亡指数明显高于对照组（分别为200．24-125．6与11．04-3．0，t=-10．193，P〈0．01）；PHPT组腺体细胞PCNA阳性率（50．5‰±11．6‰）显著高于对照组（26．7％o±2．8％0）（t=-13．120，P〈0．01），Bcl-2表达（460％0±190％o）显著高于对照组（67‰±4‰）（t=-14．120，P〈0．01）；PCNA和Bcl-2表达与腺体细胞凋亡指数均呈正相关（r值分别为0．861和0．871，P〈0．05）。结论甲状旁腺细胞增生与凋亡失衡可能是导致PHPT发生的主要原因。

Objective To evaluate the effect of proliferation and apoptosis of parathyroid cell in rabbits with primary hyperparathyroidism （ PHPT）. Methods A total of 80 adult Chinese rabbits were randomly divided into two groups （ n = 40 each）. The control group was fed with a normal diet （ Ca ： P, 1 ： 0. 7） while the experimental group a high phosphate diet （ Ca： P, 1 ： 7 ） for 3-, 4-, 5-, or 6-month intervals to establish the animal model of PHPT. The parathyroid was totally removed for pathological examination after all rabbits were sacrificed. The thyroparathyroid complex was removed en bloc, fixed in neutral formalin and prepared for histological examination. The number of parathyroid cell in PHPT was calculated. Proliferation was determined by immunohistochemistry of proliferation cell nuclear antigen （PCNA） while apoptosis assessed by in situ dUTP biotin nick-end labeling （TUNEL）. Results The number of parathyroid cell was 1.61 times in PHPT than that in the normal control （673 ± 151, 418 ±25, t = - 12. 112, P 〈 0. 01 ）. Apoptotic index （AI） increased significantly more in PHPT than that in normal control （200. 2‰ ± 125.6‰, 11.0‰ ±3.0‰, t = - 10. 193, P 〈0.01 ）. The rate of PCNA positive-cell increased significantly more in PHPT than that in control （50. 5%o ± 11.6%o, 26. 7‰ ± 2. 8‰, t = - 13. 120, P 〈 0.05 ）. So did Bcl-2 （460‰ ±190‰, 67‰ ＋4‰, t = - 14. 120,P 〈0. 05）. There was a positive correlation between AI and PCNA （r =0. 861, P 〈0. 05）. It was the same as between AI and Bcl-2 （r =0. 871, P 〈0. 05）. The value of bone mineral density decreased significantly more in PHPT than that in normal control （ 152 ＋ 34, 189 ＋ 12, t =9. 236, P 〈0. 05）. Conclusion PHPT may be mainly induced by an excessive proliferation ofparathyroid cells and an acceleration of apoptotic process.