In vitro inhibition of lipid accumulation induced by oleic acid and in vivo pharmacokinetics of chitosan microspheres (CTMS) and chitosan-capsaicin microspheres (CCMS)

Abstract

Chitosan and capsaicin are compounds extracted from natural products and have been indicated to lower body weight and prevent fatty liver. However, their applications are limited by poor oral bioavailability, low compliance and some serious side effects. To solve these problems, we successfully prepared chitosan microspheres (CTMS) and chitosan-capsaicin microspheres (CCMS) in previous study. Therefore, in the present study, we evaluated the ability of CTMS and CCMS to eliminate lipid accumulation in hepatocytesand also characterized their pharmacokinetic parameters after administration. The results showed that the two microspheres could significantly reduce intracellular lipid accumulation and dose-dependently improve the triglyceride (TG) content in HepG2 cells. A pharmacokinetic study indicated that CTMS and CCMS were distributed in almost all of the measured tissues, especially liver and kidney, and that their absorption was better than those of chitosan and capsaicin. Simultaneously, the prolonged circulating half-lives, the lower clearance and higher plasma concentration of CTMS and CCMS showed that their bioavailability was effectively enhanced. All of the results indicated that the lipid accumulation inhibition of CTMS and CCMS was better than that of chitosan and capsaicin, and that these microspheres can be developed as preventive agents for fatty liver or obesity.

Keywords: Chitosan microspheres; FBS; capsaicin-chitosan microspheres; distribution; lipid accumulation; obesity.

Figure 1.

Chemical structure of chitosan (n ≥ 2).

Figure 2.

The single labeling factors influencing the labeling efficiency included the reaction time (a), concentration of CTMS (b), mass ratio of FITC and CTMS (c), pH (d), and reaction temperature (e).

Figure 3.

Distribution and expression of CTMS and chitaosan in SD rats after treatment. The 24 hr distribution of CTMS (a) and chitosan (b), as well as the urinary (c) and faecal (d) expression of CTMS and chitosan.

Figure 4.

The mean drug concentration–time curve of capsaicin and CCMS.

Figure 5.

Distribution and expression of capsaicin and CCMS in SD rats after treatment. The 6 hr tissue distribution of capsaicin (a) and CCMS (b), as well as the 72 hr urinary (c) and faecal (d) excretion of capsaicin and CCMS.

Figure 6.

In vitro inhibiting effects of CTMS and CCMS on oleic acid-induced lipid accumulation in HepG2 cells. (a) The MTT assay results (x ± s, n = 6); (b) Oil red O staining maps of HepG2 cells; (c) Lipid accumulation inhibiting results; (d): Inhibiting effects on the TG content. Note: Vehicle: stained with only high glucose DMEMcontaining 10% FBS; Model: stained with high glucoseDMEM containing 10% FBS and 0.2mM(final concentration,same below) oleic acid; Ber (Berberine, positive):1.0 × 106 μg L−1 berberine; CTMS-H: 1.0 × 106 μg L−1715 CTMS; CTMS-M: 1.0 × 105 μg L−1 CTMS; CTMS-L:1.0 × 104 μg L−1 CTMS; CCMS-H: 1.0 × 106μg L−1CCMS; CCMS-M: 1.0 × 105μg L−1 CCMS; CCMS-L:1.0 × 104 μg L−1 CCMS. (###p < 0.001 when compared tothe control; *p < 0.05,**p < 0.01,***p < 0.001 when com-720 pared with the model).