Expression of receptor advanced glycation end products (RAGE) and histological picture of pancreatic -cells of streptozotocin-induced diabetic rats after yellow soybean powder suspension (Glycine max) administration

Abstract

Diabetes mellitus is a multisystemic disease characterized by hyperglycemia due to defects in
insulin secretion and action, or both. Hyperglycemia is the most important factor in the onset
and progress of diabetic complications. Hyperglycemia increases the expression of receptor for
advanced glycosylation end products (RAGE) which leads to pancreatic -cells damage. Yellow
soybean (Glycine max) is reported to contain isoflavones which have various biological properties
including antidiabetes. Dietary soybean can prevent the progression of diabetic complications.
This study was conducted to investigate the effects of yellow soybean powder suspension on
expression of RAGE and pancreatic -cells damage of diabetic rats. Thirty streptozotocin (STZ)-
induced diabetic Sprague Dawley male rats aged 11-12 weeks with body weight 200-250 g were
used in this study. The rats were divided into 5 groups with 6 rats in each group. Group 1 was
non diabetic rats. Group 2 was diabetic rats without treatment. Group 3-5 were given yellow
soybean powder suspension of 400, 800 and 1600 mg/kg BW for four weeks, respectively. At
the end of the experiment, pancreases tissues were removed for examination of RAGE expression
and pancreatic -cells. The results showed that yellow soybean powder suspension ingestion
signifantly decreased blood glucose level of diabetic rats toward normality (p<0.05). Moreover,
the percentage of RAGE expression on Group 3 (50.01±2.75%) and Group 2 (53.03±4.02%)
were not significantly different (p>0.05). Meanwhile, the percentage of RAGE expression on
Group 4 (42.43±4.08%) and Group 5 (40.62±3.42%) were significantly lower than Group 2
(p<0.05). The percentage of pancreatic -cells on Group 2 (10.04±1.56%) was not significantly
different compared to Group 3 (8.61±0.81%) (p>0.05), whereas the percentage of pancreatic
-cells in Group 4 (16.78±7.79%) and in Group 5 (22.03±11.51%) were significantly higher
than Group 2 (p<0.05). In conclusion, yellow soybean powder suspension can decrease RAGE
expression and prevent pancreatic -cells damage on STZ-induced diabetic rats.

Keywords: pancreatic cells - Langerhans islets - streptozotocine - diabetic rats - soybeans