山茱萸多糖对衰老大鼠晶状体中Sirt1基因表达的影响

Effect of Dogwood Polysaccharide on the Expression of Sirt1 Gene in Eye Lens of the Aging Rats

目的:初步探讨山茱萸多糖治疗年龄相关性白内障的可能机制,为其预防和治疗寻找新的药物和靶点。方法:选用60只昆明大鼠,按体质量随机分为3组,每组20只,分别为对照组(C组)、衰老模型组(A组)和山茱萸多糖给药组(D组)。在相同环境下,C组正常饮食,每日颈背部皮下注射0.9%氯化钠注射液,剂量计算参照其他给药组D-半乳糖给药量;A和D组正常饮食,每日颈背部皮下注射D-半乳糖100 mg/(kg·d);连续皮下注射45 d后,C和A组每日按照等剂量灌药量灌服温开水;D组按照多糖0.4 g/kg灌服山茱萸多糖,连续灌服30 d。试验终期颈椎离断术处死大鼠,4℃迅速取眼分离晶状体置于液氮备用。免疫组化方法检测各组间总超氧化物歧化酶(T-SOD)和总抗氧化能力(T-AOC)的变化,RT-PCR(逆转录cDNA的聚合酶链式扩增反应)检测各组Sirt1、p53和FOXO1 mRNA的表达变化。结果:A组和D组大鼠晶状体中Sirt1 mRNA的表达较C组均显著上升(P<0.05、P<0.01),且D组较A组显著上升(P<0.01);A组和D组大鼠晶状体中p53 mRNA的表达较C组显著上升(P均<0.01),而D组较A组显著下降(P<0.05);A组和D组大鼠晶状体中FOXO1 mRNA的表达较C组显著上升(P<0.05、P<0.01),且D组较A组显著上升(P<0.01)。另外A组和D组大鼠晶状体中T-SOD的活性较C组显著上升(P均<0.01),且D组较A组显著上升(P<0.01);A组和D组大晶状体中鼠T-AOC的活性较C组显著上升(P均<0.01),且D较A组显著上升(P<0.01)。结论:山茱萸多糖可能通过调节Sirt1的表达,从而调节下游基因p53和FOXO1的表达,最终抑制或延缓晶状体上皮细胞的凋亡,减缓年龄相关性白内障的进展。

OBJECTIVE：To discuss the possible mechanism of the dogwood polysaccharide for treatment of age-related cataract in an attempt to find new drugs and target, points for its prevention and treatment. METHODS： 60 Kunming mice were enrolled in our study and divided into 3 groups of 20 each ： Control group （ C）, the aging model group（A） and dogwood polysaccharide administration group（D）. In the same environment, Group C were fed with normal diet and subcutaneously injected with 0. 9% Sodium Chloride Injection in the nape daily as per the dosage of D-galactose in the other administration group; Group A and D were also fed with normal diet and subcutaneously injected with D-galactose 100 mg/（kg· d）in the nape daily; after subcutaneous injection for 45 consecutive days, Group C and Group A were fed with warm water at the same dose of drug administration; Group D was fed with dogwood polysaccharide at a dose of 0. 4 g/kg for polysaccharide for 30 consecutive days. At last all mice were killed by cervical dislocation with eye lens extracted quickly at 4 ℃ and stored in liquid nitrogen for use. T-SOD and T-AOC were detected by immunohistochemical methods, and Sirtl, p53 and FOXO1 mRNA expressions were detected by RT-PCR. RESULTS： Sirt1 mRNA in disease group and the treatment group increased significantly compared with the control group（P 〈0. 05, P 〈0. 01 ）, and Sirtl mRNA in the treatment group increased significantly compared with the disease group（P 〈0. 01 ）; p53 mRNA in disease group arid the treatment group increased significantly compared with the control group（P 〈0. 01, P 〈0. 01）, but p53 mRNA in the treatment group decreased significantly compared with the disease group（P 〈 0.05 ） ; FOXO1 mRNA in disease group and the treatment group increased significantly compared with the control group （P 〈 0. 05, P 〈 0. 01 ）, and FOXO1 mRNA in the treatment group increased significantly compared with the disease group（P 〈0. 05）. Furthermore, T-SOD and T-AOC in the disease group and the treatment group increased significantly compared with the control group （ P 〈 0.01, P 〈 0. 01 ）, and SOD and T-AOC in the treatment group increased significantly compared with the disease group （P 〈 0. 01, P 〈 0.01 ）. CONCLUSIONS： Dogwood polysaccharide may regulate the expression of downstream genes p53 and FOXO1 possibly by regulating the expression of Sirtl, ultimately inhibiting or delaying the apoptosis of epithelial cells in eye lens and slow the progression of age-related cataracts.