黄芪多糖对核糖核酸酶及其抑制因子平衡系统的保护作用

核糖核酸酶(RNase)与它的抑制因子(RI)结合,以潜伏形式存在于机体,其活力反映 RI 的水平。潜伏的 RNase%依次为:肾>肝>肺>脾。黄芪多糖抑制游离的RNase 活力的程度是:肾<肝<肺<脾。此结果应用平衡反应的相对增加速度来解释;黄芪多糖的作用在低 RI 组织表现显著。而它对正常动物的血、肾 RNase 活力无抑制作用。汞剂中毒时,血、肾 RNase 活力显著升高;预先给于黄芪多糖,能对抗汞剂的作用,使机体的核糖核酸酶及其抑制因子平衡系统维持正常,具有保护机体的作用。

英文摘要:

Astragalus Polysaccharide（APS）is a mixture isolated from Astragalus mongolicus,which has two polysaccharidcs as its major components.APS enhanced the activity of the ribonuclease inhibitor（RI）and regulated RNA metabolism and thereby affected protein biosynthesis.For ribonuclease（RNase）,there existed two states,a free form and a latent form which was a compound complexed with the RI.Tissue homogenates were incubated in the medium containing p-chloromercuribenzoic acid（PCMB）,1×10^-4M,its activity of RI was lost and thus the latent RNase which was formerly complexed with the RI was released. The latent RNase activity reflected the RI level.The RI level was different among various tissues,kidney> liver>lung>spleen.APS-2,ip 200 mg/kg per day in ICR mice for three days did not cause a significant change in total activity of RNase（latent+free）except spleen.It showed that the RI activity was enhanced by APS-2,hence the activity of free RNase decreased.The order of the inhibition rate of RNase activity by APS-2,from high to low,was spleen,lung,liver and kidney.PCMB was subcutaneously given to mice 40 mg/kg,the RNase activity increased significantly in kidney,serum and lymph node 18h later.After the medication of APS-2 ip 200mg/kg×3,the same dosage of PCMB did not cause the increase of free RNase activity,in both plasma and kidney,there existed no significant difference with the control group.Therefore, the effect of APS-2 was to counteract PCMB.The results indicated that APS may play an important role in maintaining balance between RNase and RNase-RI system.

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