Fraction SX of Maitake Mushroom Favorably Influences Blood Glucose Levels and Blood Pressure in Streptozotocin-Induced Diabetic Rats

Abstract

We assessed whether fraction SX derived from maitake mushroom could play a beneficial role in the treatment of a laboratory model of type-1 diabetes by decreasing circulating glucose levels and lowering blood pressure (BP). We injected 50 mg/kg body weight (BW) streptozotocin (STZ) intraperitoneally (i.p.) into 48 male Sprague-Dawley rats (SD) to produce a laboratory model of type-1 diabetes. SD were divided into four groups of 12 SD. A control group ate straight pulverized rat chow. To three treatment groups, we added into the pulverized rat chow: gliclazide (10 mg/kg), pioglitazone (10-30 mg/kg), or maitake SX (2.5 g/kg). In addition to measuring BW, circulating glucose level, and BP, the following procedures were also carried out: insulin challenge (insulin sensitivity), losartan challenge (renin-angiotensin system activity), Nw-nitro-L arginine-methyl ester hydrochloride (LNAME) challenge (nitric oxide [NO] system activity), and evaluation of serum angiotensin converting enzyme (ACE) activity. All treatments compared with control generally decreased circulating glucose levels, but only the maitake SX consistently enhanced measured insulin sensitivity. We found that maitake SX could significantly lower systolic blood pressure (SBP) in diabetic SD. In general, only SD receiving maitake SX, not the two drugs, showed decreased activity of the renin-angiotensin system and increased NO system activity compared with control under the conditions examined. Our results suggest that maitake SX may be useful for treating perturbations in glucose-insulin metabolism and elevated BP in type-1 diabetes.