Gallic acid protects the liver in rats against injuries induced by transient ischemia-reperfusion through regulating microRNAs expressions

Abstract

Objectives: Gallic acid (GA) is a highly effective antioxidant, which its beneficial effects are well known, but its impact on expression of microRNAs (miRs) following hepatic ischemia-reperfusion (I/R) is not well recognized. Therefore, the current research was designed to specify the beneficial effect of GA on miRs (122 and 34a), liver functional tests, and histopathological alterations beyond I/R-induced hepatic injury.

Materials and methods: Thirty-two rats were randomly divided into four groups (8 per group) including: sham-operated (S), I/R, and GA+I/R pretreated groups. Rats in sham-operated group received physiologic saline (N/S, 2 ml/kg), on a weekly basis, once a day via intraperitoneally route), then a midline abdominal surgery was performed. IR, and GA+IR pretreated groups received physiologic saline (2 ml/kg), and GA (50, and 100 mg per kg) for same time, IP, respectively, before induction of transient ischemia. One hour after reperfusion, biochemical, and histopathological evaluations were performed and expression of miRs were evaluated.

Results: The results showed that GA reduced the concentrations of liver enzymes, miR-122, and miR-34a in serum, and preserved liver cells changes induced by I/R injury.

Conclusion: These findings showed that GA has beneficial effect on liver damage induced by I/R. Therefore, it is suggested that GA can be administered as an anti-miR before elective hepatic surgeries for prevention of this complication.

Keywords: Gallic acid; Hepatic IR injury; Rat; miR-122; miR-34a.

Figure 1

Chemical structure of gallic acid (GA; 3,4,5-trihydroxybenzoicacid)

Figure 2

Liver. Ischemia-reperfusion (I/R) group. (Hematoxylin and Eosin). A: Note to large area of necrosis (White asterisk) and hemorrhage (Black asterisk) around central vein (CV) (Bar:100 µm). B: Necrotic cells are observed with dark nuclei and cytoplasm (arrows) and many erythrocytes filled the spaces between necrotic hepatocytes (asterisk)(Bar:20 µm)

Figure 3

Liver. Gallic acid 50 mg per kg (GA50) group. (Hematoxylin and Eosin). A: Necrotic area (White asterisk) and hemorrhage are observed around central vein (CV) (Bar: 100 µm). B: Note to necrotic hepatocytes (White asterisk) and erythrocytes (Black asterisk) (Bar: 20 µm)

Figure 4

Liver. Gallic acid 100 mg per kg (GA100) group. (Hematoxylin and Eosin). A: Note to small area of hemorrhage around central vein (CV) (arrow) (Bar: 100 µm). B: Erythrocytes (asterisk) are accumulated around CV (Bar: 20 µm)

Figure 5

Liver. Sham group. (Hematoxylin and Eosin). A: Note to normal structure of hepatocytes around central vein (CV) (Bar: 100 µm). B: Hepatocytes with normal nuclei and cytoplasm are situated around CV (Bar: 20 µm)

Figure 6

Gallic acid improves the expression levels of miR-122(A) and miR-34a (B), after hepatic I/R injury. βP<0.01, αP<0.001 and #P<0.0001significant difference compared to the sham-operated group. *P<0.05,**P<0.01and ***P<0.001 significant difference compared to the I/R group. I/R: Ischemia/reperfusion; S: Sham; GA: Gallic acid; GA+IR: Gallic acid pretreated I/R groups

Figure 7

Gallic acid lowered the sera levels of hepatic transaminases, and ALP after hepatic I/R injury. Data represented as mean±SEM, 8 rats in each group. αP<0.001, βP<0.01 and δP<0.05 significant difference compared to the sham-operated group. *P<0.05, **P<0.01 and ***P<0.001 significant difference compared to the I/R group. I/R: Ischemia/reperfusion;AST: Aspartate aminotransferase; ALT: Alanine aminotransferase; ALP: Alkaline phosphatase; U/l: Unit per liter

Figure 8

Gallic acid improved the serum concentrations of direct and total bilirubin following hepatic I/R injury. Results represented as mean±SEM, 8 rats in each group. βP<0.01 and δP<0.05 significant difference compared to the sham group. *P<0.05 and **P<0.01 significant difference compared to the I/R group. I/R: Ischemia/reperfusion; mg/dl: miligram/deciliter