松果体及其褪黑素影响胸腺T细胞发育周期

PINEAL GLAND AND MELATONIN INFLUENCE THE CELL CYCLE OF THYMOCYTE

目的 探讨松果体对胸腺分化发育时细胞周期的影响。 方法 选用清洁级SD大鼠 ,分为正常对照组、假手术对照组、松果体摘除、松果体摘除 +褪黑素腹腔注射 7 5mg kg组和松果体摘除 +褪黑素腹腔注射15mg kg组。术后 4、8周取材。用ABC法染胸腺cyclinA、cyclinE阳性细胞 ,计算机图像分析仪测量各阳性细胞面积及其染色强度。以碘化丙啶 (PI)一步插入性DNA定量荧光染色法 ,流式细胞术测定胸腺T淋巴细胞不同细胞周期的分布状况。以RT PCR法检测褪黑素对胸腺细胞周期依赖性激酶 1β表达的影响。 结果 松果体摘除对胸腺cyclinE表达的影响甚于对cyclinA的影响 ,促进cyclinE的合成 ,松果体摘除后胸腺细胞周期的变化表现为G1 期减少 ,S期和G2 +M期百分比增多。补充褪黑素后上述改变有所恢复 ,但与剂量不成线性关系 ,且对皮髓质影响有所不同。褪黑素能促进胸腺细胞表达细胞周期依赖性激酶 1β。 结论 松果体摘除能显著影响胸腺细胞分化发育 ,补充褪黑素能缓解相关影响。

Objective To study the effect of pinealctomy and melatonin on the cell cycle distribution during T cell development in thymus. Methods SD rats were divided into 5 groups:normal controls,sham-operated controls,pinealectomy,pinealectomy+melatonin injection 7.5 mg/kg; and pinealectomy+melatonin injection 15 mg/kg.The animals were sacrificed at 4 or 8 weeks after operation.cycilnA +and cyclinE +T cells in thymus were dyed with immunocytochemical ABC methods, measured by computer image analysis.Cell cycle analysis was performed by flow cytometry.The expression of cyclin-dependent kinase inhibitor 1β was tested by RT-PCR method. Results The effect of pinealectomy on the expression of cyclinE was stronger than that of cycilnA. Pinealectomy promotes the synthesis of cyclinE in thymus.The percentage of G-0/G-1 phase cells was decreased and G-2/M phase cells was increased.These would be convalescente by supplement with melatonin,but the reaction to melatonin was differencet in thymus cortex and in medulla.Melatonin enhanced the expression of cyclin-dependent kinase inhibitor 1β in thymus.Conclusion Pinealectomy influences notably the T cells development in thymus.Rejuvenation of degenerative thymus could be observed by melatonin administration.