Effects of polysaccharides from Dendrobium officinale on expression of Bax and Bcl-2 in vascular endothelial cells induced by high sugar / 中国药理学通报

ABSTRACT

Aim To optimize extraction of polysaccha-rides from Dendrobium officinale ( DOP ) and investi-gate the effects of DOP on the expression of Bax and Bcl-2 in vascular endothelial cell of human umbilical vein ( HUVEC) by the induction of high sugar. Meth-ods Response surface methodology ( RSM ) was em-ployed to optimize the conditions for extraction of DOP on the basis of single factor experiment. The HUVEC cells were divided into the blank control group, the normal blood sugar group, the high sugar stimulation group and different drug concentration group plus the high sugar stimulation group. The growth condition of cells was examined by methyl thiazolyl tetrazolium ( MTT) , and RT-PCR was used to detect the expres-sion of Bcl-2 Assaciated X protein ( Bax ) and B-cell lymphoma-2 ( Bcl-2 ) in vascular endothelial cells after 24 and 48 hours. Results The optimal extraction time was 2 h and the optimal liquid-solid ratio was 15. 75∶1 ( mL/g ) , and the optimal extraction frequency was 2. 8. Under these optimized conditions, the extraction rate of polysaccharides was 25. 1%, while the experi-mental extraction rate was 24. 9%, which was highly fit with the regression model. Compared with normal sugar group, high sugar group reduced the growth of cells and enhanced the expression of Bax, and inhibi-ted the expression of Bcl-2 . DOP promoted the growth of cells in high sugar induction, inhibited the expres-sion of Bax, and enhanced the expression of Bcl-2. Conclusions The process optimized through RSM has the extraction effect, and has certain practical signifi-cance. Through the down-regulation of the expression of Bax in vascular endothelial cells and the up-regula-tion of the expression of Bcl-2 by the induction of high sugar, DOP can restrain HUVEC, which could prevent and cure diabetic angiopathy to some extent.