地黄多糖干预对低剂量X线照射小鼠生精细胞P53和bcl-2蛋白表达的影响

Effects of Rehmannia Glutinosa Polysaccharide on the expressions of P53 and bcl-2 protein in mouse germ cells exposed to repeated low-dose X-ray irradiation

目的探讨地黄多糖干预对低剂量x线照射损伤小鼠生精细胞中p53和bcl-2蛋白水平表达的影响。方法选择70只雄性昆明小鼠（5～6周龄；体重22±2g），随机分为：单纯照射组（1—3组），给药照射组（4～9组）和正常对照组（10组）。所有小鼠自照射前5d开始每天灌胃一次，分别给予0．2mL生理盐水灌胃（1—3组和10组）和地黄多糖（溶于0．2mL生理盐水）200mg／Kg（4-6组）、800mg／Kg（7-9组），共24次。照射组自第6天起采用X线每天一次全身照射，共15次；单次照射剂量分别为0．025、0．075、0．100Gy，剂量率为0．025Gy／min。所有小鼠在末次照射结束后48小时内脱颈法处死摘取睾丸，经Bouin氏液固定24h后石蜡包埋、切片。采用HE染色观察睾丸生精小管形态结构，免疫组织化学法检测生精细胞中P53及bcl-2蛋白的表达水平。结果随着单次低剂量X线照射剂量增加，HE染色可见照射组小鼠睾丸生精小管各级生精细胞数目逐渐减少，结构排列出现不同程度的紊乱；免疫组织化学可见生精细胞中p53蛋白表达水平逐渐增加，而bcl-2蛋白表达水平则逐渐下降。给予200mg／Kg及800mg／Kg地黄多糖灌胃能下调生精细胞中p53蛋白和上调bcl-2蛋白表达水平，但后者对p53及bcl-2蛋白表达水平调节作用更明显，两者具有显著统计学意义（P〈0．05）。结论地黄多糖对低剂量x线全身照射小鼠的损伤生殖功能有一定保护作用，其抗辐射作用机制部分可能与下调生精细胞qhp53蛋白、上调bcl-2蛋白表达水平有关。

Objective To explore the effects of Rehmannia Glutinosa Polysaccharide on the expressions of P53 and bcl-2 protein in mouse germ cells exposed to repeated low-dose X-ray irradiation. Methods Total of 70 male mice （5-6 weeks old; weight 22 ± 2g） were selected in this study and randomly divided into four groups such as group A （irradiation group, 21 mice）, group B （radiation and 200mg/Kg RPS fed group, 21 mice）, group C （radiation and 800mg/Kg RPS fed group, 21 mice）, group D （the control group, 7 mice）; and then mice in group A, B and C were subdivided into 3 groups and each group had 7 mice. On 5th day before irradiation, the mice in groups A and D were intragastrically administrated with 0.2mL saline, and mice in group B and group C were intragastricaUy given with 200mg/Kg, 800mg/Kg Rehmannia Glutinosa Polysaccharide which were dissolved in 0.2mL saline. Intragastrical administration was performed for a total of 24times. The mice in group A, B and C received low-dose whole body X-irradiation for 15 times; The single irradiation doses were 0.025, 0.075 and 0.100Gy with dose rate 0.025Gy/min. Mice were sacrificed in 48 hours aRer the last irradiation, their testes were removed and fixed in Bouin＇s solution for 24 hours, then cmbedded in paraffin and sliced. The morphology of testicular seminiferous tubules was observed and the expressions of P53 and bcl-2 protein in germ cells were detected by immtmohistochemistry. Results With the increasing single dose of X-ray irradiation, HE staining showed that the number of germ cells in the testis of the mice in the irradiation group was decreased, and the disorder of the structural arrangement apibeared in different degrees. The immunohistochemical analysis showed that the protein level of P53 gradually increased while the bcl-2 protein level decreased in spermatogenic cells gradually. Both 200mg / kg and 800mg/Kg Rehmannia glutinosa polysaccharides Given orally can downregulate the expression of p53 protein and upregulate the expression of bcl- 2 protein in germ cells, but it is more remarkable in the group of 800mg/Kg Rehmannia glutinosa polysaccharides, and there was a statistical differences （P〈0.05）. Conclusion Rehmannia glutinosa Polysaccharide shows a protective effect for the reproductive function of mice with X-irradiation damage, which may be related to downregulation of P53 protein, and upregulation of of bcl-2 protein in spermatogenic cells.