Application of Bacillus sp. COX-T3 Cholesterol Oxidase in Reduction of Serum Cholesterol and Body Weight Management in a Murine Model

Abstract

To examine the effect of purified cholesterol oxidase (COX) of a Bacillus sp. COX-T3 for treating high-lipid diet-induced hypercholesterolemia, an experimental mouse model was established. The enzyme was purified by using a Riboflavin-Sephadex G-25 affinity column. After keeping mice assigned to Group 1 to 5 on a high fat diet, the mice showed 14.4, 20.6, 24.4, 19.4 and 17.0 % body weight gain, respectively (mean body weight gain of ~19.0 %) over 9 weeks of intake of high-fat feed. The maximum body weight was attained in the mice assigned to Group 3 (32.73 ± 2.11 g) in comparison to the control regimen kept on normal diet for the same period of time. The results reflected the successful establishment/development of a near obese mouse model by intake of high-fat diet for 9 weeks. The cholesterol level in the high-fat diet fed mice significantly increased with age up to 6th week. For the Group 1 to 5, the high fat diet caused a significant increase of serum cholesterol. The purified COX was intra-muscularly administered to the mice at 0.1 to 0.5 U/dose (100 μl) on alternate days for 5 weeks. The mice assigned to treatment group(s) 3, 4 and 5 showed 2.2, 2.2 and 3.5 % decline in their average body weight(s) that indicated a dose/ concentration dependent effect of administration of Bacillus sp. COX-T3 in bringing a reduction in the body weight(s) of these mice. The reduction of serum cholesterol level by 45.3, 40.9, 22.4, 28.4 and 40.7 % in Group 1 to 5, respectively, was achieved in comparison to the serum cholesterol levels recorded after 9 weeks of intake of high fat diet in mice. Interestingly, the addition of the bacterial COX at 1.2 U.ml-1 concentrations to the Hep2C cells slightly promoted the cell viability while the COX at 1.8 U.ml-1 exerted a cytotoxic effect on the cell growth as reflected by ~10.6 % decline in the cell viability recorded in MTT assay. The observed data indicated a successful therapeutic application of the purified COX of Bacillus sp. COX-T3 in treating an obese hypercholesterolemic murine model over a reasonable period of enzymatic treatment.