Regulation of polygonati polysaccharide on expression of glycosylated end-product receptor mRNA in cardiac and renal tissues of diabetic mice

Youyuan LI; Hongbo DENG; Rong WANG; Shenrong WU

ABSTRACT

BACKGROUND:

Siberian solomonseal rhizome is a sort of Chinese traditional medicine for anti-senilism. The effective component, poly gonati polysaccharide, has the effects of reducing blood glucose and glycosylhemoglobin.

OBJECTIVE:

To assay regulative effect of polygonati polysaccharide on expression of the key substance of non-enzymic glycosylation of proteinsglycosylated end-product receptor mRNA by reverse transcriptase polymerase chain reaction, so as to develop effective inhibitor for non-enzymic glycosylation of proteins and provide experimental evidences for preventing diabetes and its complications.

DESIGN:

Randomized control animal trial

SETTING:

Department of Geriatrics, the Second Xiangya Hospital, Central South University; Department of Cardiology, Haikou Hospital Affiliated to Xiangya Medical College, Central South University.MATERIALS The experiment was completed in Animal Room of Second Xiangya Hospital of Central South University form March to June 2004. A total of 30 BALB/C mice of clean grade were selected and randomly divided into normal control group, model control group and polygonati polysaccharide group, with 10 in each group.

METHODS:

Diabetic models were established by intraperitoneal injection with streptozotocin to mice in model control group and polygonati polysaccharide group. Model establishment would be regard as successful if blood glucose of mouse was 8.0 mmoL/L or above. Mice in polygonati polysaccharide group were treated with polygonati polysaccharide (2 mL/kg per day), while mice in normal control group and model control group were treated with injection of 0.5 mL water once a day for 12 consecutive weeks.After medicine had been given to the mice, they were put to death by decapitation. Reverse transcriptase polymerase chain reaction was used to assay expression of glycosylated end-product receptor mRNA in cardiac and renal tissues of experimental animals.MAIN OUTCOME

MEASURES:

① Observation of general situation of mice in each group 12 weeks later after model establishment. ② Change of blood glucose of mice in each group before and after model establishment.③ Gel electrophoretic maps of glycosylated end-product receptor mRNA in cardiac and renal tissue of mice in each group. ④ Semi-quantitative assay of glycosylated end-product receptor in cardiac and renal tissue of mice in each group

RESULTS:

All the 30 mice entered the results analysis. ① Observation of general situation of mice in each group 12 weeks later after model establishment mice in normal control group gained weight and moved freely; mice in model control group manifested the symptoms of losing weight, polyuria, listlessness, lags in response etc.; mice in polygonati polysaccharide group manifested milder symptom of polyuria and more sensitive in responses as compared with model control group.② Changes of blood glucose of mice in each group before and after model establishment blood glucose levels were similar between normal control group and model control group before and after model establishment (P ＞ 0.05), while blood glucose in polygonati polysaccharide group significantly decreased 12 weeks later after model establishment [(10.05±1.16), (7.18±0.84) mmoL/L, P ＜ 0.05]. ③ Gel electrophoretic maps of glycosylated end-product receptor mRNA in cardiac and renal tissue of mice in each group Compared with normal control group, the expression of glycosylated end-product receptor mRNA increased in cardiac and renal tissue of mice in model control group, while the expression in polygonati polysaccharide group significantly decreased as compared with model control group. ④ Semi-quantitative assay of glycosylated end-product receptor in cardiac and renal tissue of mice in each group the relative value of glycosylated end-product receptor to β-actin in cardiac and renal tissue of mice in model control group was significantly higher than normal control group (P ＜ 0.01); however, the relative value of polygunati polysaccharide group significantly decreased as compared with model control group (0.760±0.121,0.998±0.202;0.609±0.146;0.765±0.113; P ＜ 0.05).

CONCLUSION:

Besides reducing blood glucose, polygonati polysaccharide can significantly down regulate high expression of glycosylated endproduct receptor mRNA in cardiac and renal tissue of mice with diabetes, so as to inhibit the combining sites for glycosylated end-products and a series of cytobiological reactions after combined with their receptors, and protect the target organs and tissues from injuring by hyperglycemia.