Chitosan treatment abrogates hypercholesterolemia-induced erythrocyte's arginase activation

Abstract

This study aimed to evaluate the protective effect of chitosan (CS) against hypercholesterolemia (HC) induced arginase activation and disruption of nitric oxide (NO) biosynthesis using erythrocytes as cellular model. Human erythrocytes were isolated and classified into eight groups. Next, cells were treated with l-arginine (l-ARG), N^ω-nitro-l-arginine methyl ester (l-NAME), CS or CS + l-ARG in the presence of normal plasma or cholesterol enriches plasma. Then, erythrocytes were incubated at 37 °C for 24 h. The present results revealed that, HC induced significant increase of cholesterol inclusion into erythrocytes membrane compared to control. Moreover, HC caused significant decrease in nitric oxide synthase (NOS) activity similar to l-NAME; however, arginase activity and arginase/NOS ratio significantly increased compared to control. On contrast, treatment of HC with, l-arginine, CS or CS plus l-arginine prevents HC induced cholesterol loading into erythrocytes membrane, NOS inhibition and arginase activation. This study suggested that CS could be protective agent against HC induced disruption of erythrocyte's oxidative status and arginase activation.

Keywords: Arginase; Chitosan; Erythrocytes; Hypercholesterolemia; Nitric oxide.

Figure 1

Effect of CS, l-NAME, l-ARG, HC and CS + l-ARG on percent of cholesterol inclusion into erythrocytes membrane compared to normal control. One-way analysis of variance used for data analysis; Tukey’s posttest was used to determine the statistical differences between groups. Results were represented as M ± SD (N = 6). Superscript letters indicated when significant differences observed from either control group or HC group. ^a Significantly increase from control. ^b Significantly decrease from HC. P ⩽ 0.05.

Figure 2

Effect of CS, l-NAME, l-ARG, HC and CS + l-ARG on sialic acid content of erythrocyte membrane compared to control erythrocytes. One-way analysis of variance used for data analysis; Tukey’s posttest was used to determine the statistical differences between groups. Results were represented as M ± SD (N = 6). Superscript letters indicated when significant differences observed from either control group or HC group. ^a Significantly decrease from control. ^b Significantly increase from HC. P ⩽ 0.05.

Figure 3

Effect of CS, l-NAME, l-ARG, HC and CS + l-ARG on plasma total antioxidant status compared to control plasma. One-way analysis of variance used for data analysis; Tukey’s posttest was used to determine the statistical differences between groups. Results were represented as M ± SD (N = 6). Superscript letters indicated when significant differences observed from either control group or HC group. ^a significantly decrease from control. ^b significantly increase from HC. P ⩽ 0.05.