Preparation and evaluation of anti-Helicobacter pylori efficacy of chitosan nanoparticles in vitro and in vivo.

The aim of this study was to formulate and systematically evaluate in vitro and in vivo Helicobacter pylori (Hp) efficacy of chitosan (CS) nanoparticles (NPs). CS NPs were prepared by the polymerid dispersion method. The in vitro anti-Hp effect of concentration, pH and deacetylation degree of CS NP solutions was detected. Then, 60 BALB/c mice were randomly divided into 3 groups and Hp-infected mice were established by inoculating with Hp strain. Thereafter that, mice in different groups received PBS, CS solution of CS NP solution intragastrically, twice daily for 14 consecutive days. Four weeks after the last administration, the mice were killed and part of the gastric mucosa was embedded in paraffin, cut into sections and assayed with Giemsa staining. Part of the gastric mucosa was used to quantitatively culture Hp. At pH 4-6, the anti-Hp effect of CS NP solution had a negative correlation with pH value (P < 0.01), and the optimal pH value was 4; there was a significant difference in anti-Hp effect between 88.5% deacelytation degree (DD88.5) CS NP and 95% deacelytation degree (DD95) CS NP (P < 0.05-0.01). The anti-Hp effect ranked from high to low, i.e., from DD95 CS NP to DD88.5 CS NP; the anti-Hp effect of DD88.5 CS NP and DD95 CS NP showed no difference within between 5 and 20 g/l (P > 0.05). The Hp eradication rate was 0, 55 and 75%, respectively, among the three groups (P < 0.01) and the Hp colonized density in the control group and CS group was significantly higher than that in the CS NP group (P < 0.01, 0.05). These results suggest that CS NP improves the anti-Hp efficacy of CS in vitro or in vivo and has the potential to kill Hp directly.