慢性肾功能衰竭继发性甲状旁腺机能亢进症患者甲状旁腺细胞凋亡及调节因素的研究

Apoptosis in papathyroid of uremic patients with secondary hyperpapathyroidism and the influence of Ca 2+ and calcitriol on APO

目的探讨慢性肾功能衰竭（ＣＲＦ）继发性甲状旁腺机能亢进症（甲旁亢）患者甲状旁腺细胞凋亡状况及Ｃａ２＋、钙三醇对其影响。方法采用ＤＮＡ凝胶电泳和ｄＵＴＰ生物素标记法观察ＣＲＦ继发性甲旁亢患者甲状旁腺组织中细胞凋亡的发生率。结果原发性、继发性甲旁亢患者甲状旁腺组织中凋亡细胞百分率显著的高于正常人，分别为（３．９±０．７）％、（５．６±０．８）％和（１．３±０．４）％，继发性甲旁亢患者甲状旁腺细胞经高浓度Ｃａ２＋培养２４小时和钙三醇培养９６小时后甲状旁腺原位细胞凋亡率显著增加，分别为（９．１±０．５）％，（８．９±０．７）％。结论ＣＲＦ继发性甲旁亢患者甲状旁腺细胞凋亡明显增加，细胞外高Ｃａ２＋、钙三醇使甲状旁腺细胞凋亡增加。

Objective To examine whether the alteration of apoptosis is present in parathyroid (PT) tissue of hyperparathyroidism (HPTH). Methods DNA strand breaks were sought by TdT mediated dUTP nick end labeling assay (TUNEL) and DNA gel electrophoresis in 4 specimens of normal PT tissue, 7 of primary HPTH (Ⅰ° HPTH) and 9 of secondary HPTH tissue (Ⅱ° HPTH). Results The data showed that the percentage of apoptotic cells was (1.3±0.4)% in normal PT, (3.9±0.7)% in Ⅰ° HPTH and (5.6±0.8)% in Ⅱ° HPTH ( P <0 04), Ⅰ° HPTH vs normal PT; P <0.001, Ⅱ° HPTH vs normal PT respectively. There was no significant difference in the apoptotic incidence beteen Ⅰ° and Ⅱ° HPTH. In vitro study, a greater amount of apoptotic TUNEL positive cells was found 24 hours after exposure to high Ca 2+ (1.9 mmol/L) than to low Ca 2+ (0.5 mmol/L) concentration and 96 hours after treatment with high calcitriol (10 -7 mol/L) than with low calcitriol (10 -11 mol/L) concentration. However, no DNA ladder feature was observed in electrophoresis of DNA extracted from cultured parathyroid cells of HPTH. Conclusion It was shown that apoptosis did not decrease, but actually enhanced, in hyperplastic parathyroid tissue of patients with Ⅰ° or Ⅱ° HPTH and that a high extracelluar concentration of either Ca 2+ or calcitriol was capable of enhancing apoptosis in human parathyroid cells of Ⅱ° HPTH complicating chronic renal failure.