The Intestinal Zonulin and Zonula Occludens 1 Protein Expression and Lipopolysaccharide Levels In ddY Mice Injected with Dengue Virus Non-Structural Protein 1

Background and Objective: Dengue virus infection remains a health problem. Dengue Virus Non-Structural protein 1 (NS1) increases the release of proinflammatory cytokines that induce intestinal zonulin expression. As a result, the ZO-1 protein translocates to the cytoplasm, which increases enterocyte permeability. This study aimed to investigate the effects of dengue NS1 on intestinal zonulin and ZO-1 expression, intestinal weight, and serum LPS. Methods: This experiment used 18 ddY mice with a pre-posttest control group design. Mice were randomly divided into control (C), PBS (T1), and PBS+NS1 (T2) groups. Mice in the T1 and 2 groups were intravenously injected with 500 µL PBS and 50 µg NS1, respectively. Blood samples were collected before and after the three-day treatment. The intestines were weighted directly and were then embedded with formalin for immunostaining. Serum LPS were determined using ELISA. Data were analyzed using paired t-test and ANOVA. Results: The T2 group had the highest zonulin expression (histoscore=8) compared to the T1 (histoscores=7.33) and C (histoscore=6.33) groups but were not significant (p=0.135). Intestinal ZO-1 expression did not increase in the T groups compared to the C group (p=0.368). The intestine weight in the C group was significantly lower than the T group (p=0.001). After treatment, serum LPS levels in the T2 group were higher (0.34 pg/mL) than before treatment (0.12 pg/mL; p=0.118), but not in the T1 group (p=0.384). Meanwhile, there was a significant decrease in serum LPS levels in the C group (p=0.046). Conclusion: injection of 50 µg dengue virus NS1 has a minor effect on intestinal permeability in ddY mice.