Effect of polysaccharide from Bacillus subtilis sp. on cardiovascular diseases and atherogenic indices in diabetic rats

BACKGROUND: Diabetes mellitus induces chronic complications such as cardiovascular damage, cataracts and retinopathy, nephropathy, and polyneuropathy. The main aim of the study was to isolate and identify both of bacterial strain and exopolysaccharide to assess the possible efficiency of exopolysaccharide (BSEPS) from Bacillus subtilus sp .suppress on cardiovascular diseases, atherogenic and coronary risk indices in diabetic rats. METHODS: The bacterial strain used was isolated from mangrove tree sediment by serial dilution and the spread-plate technique and identified by morphological, physiological, and biochemical characteristics, and by 16S rRNA analysis. The BSEPS was extracted from the bacterial supernatant by four volumes child ethanol then the functional groups, MW and chemical analysis were detected by Fourier-transform infrared (FTIR), gel permeation chromatograph (GPC) and High-performance liquid chromatography (HPLC). Also an antioxidant activity was measured by using 2,2-diphenyl-1-picrylhydrazyl (DPPH). Thirty-two male Sprague–Dawley rats were equally randomized into four groups: control group supplemented with normal saline (Group I); the second group supplemented with BSEPS (Group II); diabetic group supplemented with normal saline (Group III) and the diabetic group supplemented with BSEPS (Group IV). Diabetes was induced by Streptozotocin (STZ) (65 mg/kg BW) intraperitoneally. BSEPS (100 mg/kg BW) was administered orally for four weeks, following STZ induction. RESULTS: The isolated strain was identified based on 16S rRNA sequence as Bacillus subtilis sp. suppress. A preliminary chemical analysis of BSEPS indicated that the monosaccharides were mannuronic acid, glucuronic acid, glucose, galactose, and mannose in a molar ratio of 1.6:1.5:1.0:2.3:1.4, respectively, with a molecular weight of 1.66 × 10(4) g mol(−1) and a molecular number of 7.64 × 10(3) g mol(−1). BSEPS inhibited 2,2-diphenyl-1-picrylhydrazyl radical activity, and BSEPS supplement reduced glucose (p < 0.05) and troponin levels while insulin levels increased (p < 0.05). BSEPS also reduced total serum cholesterol, low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), and triglycerides, and elevated high-density lipoprotein-cholesterol (HDL). In parallel, intercellular adhesion molecule (ICAM), and vascular cell adhesion molecule (VCAM) levels in STZ-induced diabetic rats were reduced. Moreover, polysaccharides reduced atherogenic and coronary risk indices, which were confirmed by histopathological examination of the heart and aorta. CONCLUSIONS: Our study suggests that BSEPS improves hyperglycemia, dyslipidemia, and cardiovascular disease risk in STZ-induced diabetic rats.