Time-Dependent Plasma Protein Changes in Streptozotocin-Induced Diabetic Rats before and after Fungal Polysaccharide Treatments

Abstract

Previous studies about protein modulation with chemically induced models of diabetes in animals have yielded conflicting results, in that many investigators have reported different regulation patterns for the same proteins. Therefore, it is reasonable to determine biomarkers for prognosis and diagnosis of diabetes with time profiling for the candidate proteins. In this regard, we examined the influence of hypoglycemic fungal polysaccharides (EPS) on the time-dependent plasma protein alterations in streptozotocin-induced diabetic rats. The 2-DE analysis of rat plasma demonstrated that about 50 proteins from about 900 visualized spots were found to be differentially regulated, of which 20 spots were identified as principal diabetes-associated proteins. The results of time profiling revealed that most of the identified proteins showed significant alterations in a time-dependent manner during 14 days, with notable trends. Nine out of the twenty proteins displayed very similar time profiles between normal healthy and EPS-treated diabetic rats. Interestingly, the altered profiles of several proteins by diabetes induction almost returned to control levels after EPS treatments. In particular, we found a clear distinction in differential expression of oxidative stress proteins (ceruloplasmin and transferrin) and lipid metabolism related proteins (Apo A-I, Apo A-IV, and Apo E) in the STZ-induced diabetic rats. The data presented here have identified and characterized the time-dependent changes in plasma proteins associated with EPS treatment in STZ-induced diabetic rats, thereby leading to the discovery of early-response and late-response biomarkers in diabetic and EPS-treated states.

Hypoglycemic effect of crude exopolysaccharides produced byCerrena unicolor,Coprinus comatus, andLenzites betulinaisolates in streptozotocin- induced diabetic rats

“…Additionally, it is widely used to induce IDDM in experimental animal models . However, Kim et al (2006aKim et al ( , 2006b reported that fungal EPS might neutralize the ability of STZ to cause -cell damage or induce regeneration of islet -cells. EPS administration after STZ treatment restored serum insulin and glucose levels.…”

Gene expression profiling in streptozotocin-induced diabetic rat liver in response to fungal polysaccharide treatment

“…previously [13][14][15]. In brief, diabetes was induced by intravenous injection of streptozotocin (50 mg/kg body weight, dissolved in 0.01 M sodium citrate buffer, pH 4.5).…”

“…All the animals were randomly divided into three groups with six animals in each group: normal healthy control group (N group), normal rats received 0.9% NaCl solution; STZ-induced diabetic group (STZ group), diabetic rats treated with 0.9% NaCl solution; EPS-treated diabetic group (EPS group), diabetic rats treated with EPS at the level of 200 mg/kg body weight daily for 14 days. The EPS-fed control group was excluded in this study because of similar physiological status to normal control group as described in our previous studies [14,15]. These experiments were approved by the Committee for Laboratory Animal Care and Use, Daegu University.…”

“…More recently, we obtained interesting results using those polysaccharides that plasma proteome was significantly altered in STZ-induced diabetic rats in response to polysaccharide therapy [14,15].…”

Differential expression of liver proteins in streptozotocin-induced diabetic rats in response to hypoglycemic mushroom polysaccharides

“…The extract of P. baumii is known to have various biological activities including inhibition of pulmonary inflammation, antioxidant and free radical scavenging activities [6,7]. In our previous consecutive studies [8][9][10], we have found that the fungal extracellular polysaccharides (EPS) produced by mycelial culture of a medicinal mushroom P. baumii has a strong antidiabetic activity against streptozotocin (STZ)-induced diabetic rats. In addition, it was also observed that the EPS significantly altered and particularly normalized dysregulated plasma proteins in STZ-induced diabetic rats in a time-dependent manner.…”