Effect of artesunate supplementation on bacterial translocation and dysbiosis of gut microbiota in rats with liver cirrhosis

Abstract

Aim: To evaluate the effect of artesunate (AS) supplementation on bacterial translocation (BT) and gut microbiota in a rat model of liver cirrhosis.

Methods: Fifty-four male Sprague-Dawley rats were randomly divided into a normal control group (N), a liver cirrhosis group (M) and a liver cirrhosis group intervened with AS (MA). Each group was sampled at 4, 6 and 8 wk. Liver cirrhosis was induced by injection of carbon tetrachloride (CCl4), intragastric administration of 10% ethanol, and feeding a high fat diet. Rats in the MA group were intragastrically administered with AS (25 mg/kg body weight, once daily). Injuries of the liver and intestinal mucosa were assessed by hematoxylin-eosin or Masson's trichrome staining. Liver index was calculated as a ratio of the organ weight (g) to body weight (g). The gut microbiota was examined by automated ribosomal intergenic-spacer analysis of fecal DNA. BT was assessed by standard microbiological techniques in the blood, mesenteric lymph nodes (MLNs), liver, spleen, and kidney.

Results: Compared to group N, the body weight was reduced significantly in groups M and MA due to the development of liver cirrhosis over the period of 8 wk. The body weight was higher in group MA than in group M. The liver indices were significantly elevated at 4, 6 and 8 wk in groups M and MA compared to group N. AS supplementation partially decreased the liver indices in group MA. Marked histopathologic changes in the liver and small intestinal mucosa in group M were observed, which were alleviated in group MA. Levels of pro-inflammatory interleukin-6 and tumor necrosis factor-α were significantly elevated at 8 wk in ileal homogenates in group M compared to group N, which were decreased after AS supplementation in group MA. The dysbiosis of gut microbiota indicated by the mean diversity (Shannon index) and mean similarity (Sorenson index) was severe as the liver cirrhosis developed, and AS supplementation had an apparent intervention effect on the dysbiosis of gut microbiota at 4 wk. The occurrence of BT was increased in the liver of group M compared to that of group N. AS supplementation reduced BT in group MA at 8 wk. BT also occurred in the MLNs, spleen, and kidney, which was reduced by AS supplementation. BT was not detected in the blood in any group.

Conclusion: Dysbiosis of gut microbiota, injury of intestinal mucosal barrier and BT occurred as liver cirrhosis progressed, which might enhance inflammation and aggravate liver injury. AS may have other non-antimalarial effects that modulate gut microbiota, inhibit BT and alleviate inflammation, resulting in a reduction in CCl4, alcohol and high fat-caused damages to the liver and intestine.

Keywords: Artesunate; Bacterial translocation; Gut microbiota; Hepatic cirrhosis; Intervention.

Figure 1

Body weight and organ indices in rats. A: Body weight; B: Liver index. ^bP < 0.01 vs N group at 4 wk; ^dP < 0.01 vs N group at 6 wk; ^fP < 0.01 vs M group at 6 wk; ^hP < 0.01 vs N group at 8 wk; ^jP < 0.01 vs M group at 8 wk.

Figure 2

Histopathological changes of hepatic tissues as revealed by HE staining (n = 6, × 200). A: N; B: M at 4 wk; C: MA at 4 wk; D: M at 6 wk; E: MA at 6 wk; F: M at 8 wk; G: MA at 8 wk.

Figure 3

Histopathological changes of hepatic tissues as revealed by Masson’ trichrome staining (n = 6, × 200). A: N; B: M at 4 wk; C: MA at 4 wk; D: M at 6 wk; E: MA at 6 wk; F: M at 8 wk; G: MA at 8 wk.

Figure 4

Histopathological change of small intestinal mucosa as revealed by HE staining (n = 6, × 200). A: N; B: M at 4 wk; C: M at 6 wk; D: M at 8 wk; E: MA at 4 wk; F: MA at 6 wk; G: MA at 6 wk.

Figure 5

Levels of TNF-α and IL-6 in the tissue homogenates of liver and ileum (n = 6). A: The levels of TNF-α; B: The levels of IL-6. ^aP < 0.05, ^bP < 0.01 vs N group; ^cP < 0.05 vs M group.