Hepatoprotective Effect of Baicalein Against Acetaminophen-Induced Acute Liver Injury in Mice

Abstract

Baicalein (BAI), one of the main components of Scutellaria baicalensis Georgi, possesses numerous pharmacological properties, including anti-cancer, anti-oxidative, anti-virus and anti-bacterial activities. The purpose of this study was to evaluate the hepatoprotective effect of baicalein against acetaminophen (APAP)-exposed liver injury in mice, and elucidate the underlying hepatoprotective mechanism. Baicalein pretreatment significantly alleviated the elevation of IL-6, IL-1β and TNF-α in serum and hepatic in a dose-dependent manner. It also dose-dependently reduced the hepatic malondialdehyde (MDA) concentration, as well as the depletion of hepatic superoxide dismutase (SOD), hepatic glutathione (GSH) and hepatic catalase (CAT). Moreover, pretreatment with baicalein significantly ameliorated APAP-exposed liver damage and histological hepatocyte changes. Baicalein also relieved APAP-induced autophagy by regulating AKT/mTOR pathway, LC3B and P62 expression. Furthermore, the hepatoprotective effect of baicalein to APAP-induced liver injury involved in Jak2/Stat3 and MAPK signaling pathway. Taken together, our findings suggested that baicalein exhibits the ability to prevent liver from APAP-induced liver injury and provided an underlying molecular basis for potential applications of baicalein to cure liver injuries.

Keywords: acetaminophen; autophagy; baicalein; inflammation; liver injury.

Figure 1

Structural formula of BAI.

Figure 2

Effects of BAI on serum enzyme activity. 1h after the last dose of BAI, APAP (350 mg/kg) was administered (n = 8/group). Blood was harvested at 24h post-APAP. We harvested serum for an analysis of alanine transaminase (ALT) (A) and aspartate aminotransferase (AST) (B). All data are expressed as mean ± SD., n = 8. ** p < 0.01, * p < 0.05 compared with model group; ^## p < 0.01, ^# p < 0.05 compared with control group.

Figure 3

Inhibition of APAP-induced acute liver injury by BAI. Representative sections of liver stained with hematoxylin and eosin (H&E), n = 5. Original magnification: 100× and 400×.

Figure 4

Pretreatment with BAI protected against APAP-induced liver injury: Effects of BAI on the hepatic of glutathione (GSH) (A), malondialdehyde (MDA) formation (B), superoxide dismutase (SOD) (C), CAT (D) in APAP-induced mice; values are expressed as the mean ± S.D., n = 8. * p < 0.05, ** p < 0.01 compared with the model group; ^# p < 0.05, ^## p < 0.01 compared with control group.

Figure 5

Effects of BAI on serum inflammatory responses. TNF-α (A), IL-6 (B)and IL-1β (C) levels from mice in each experimental group were determined by commercial kits. All data are expressed as mean ± S.D., n = 8. * p < 0.05, ** p < 0.01 compared with the model group; * p < 0.05, ** p < 0.01 compared with the control group.

Figure 6

Effects of BAI on liver inflammatory responses. TNF-α (A), IL-6 (B) and IL-1β (C) levels from mice in each experimental group were determined by commercial kits. All data are expressed as mean ± S.D., n = 8. * p < 0.05, ** p < 0.01 compared with the model group; ^# p < 0.05, ^## p < 0.01 compared with control group.

Figure 7

Effects of BAI on p-AKT, AKT, p-mTOR, mTOR, P62and LC3B protein expression. Protein samples were extracted from liver tissue homogenates and analyzed by western blot. Effects of BAI on APAP-induced p-AKT, AKT, p-mTOR, mTOR, P62and LC3B in liver and statistical analysis of p-AKT, AKT, p-mTOR, mTOR, P62and LC3B protein expression (A–D). Control, APAP group; 50 mg/kg, 100 mg/mg BAI group; All data are expressed as mean ± S.D., n = 3. ** p <0.01, * p < 0.05 compared with model group; ^## p < 0.01, ^# p < 0.05 compared with control group.

Figure 8

Effects of BAI on p-P38, P38, p-JNK, JNK, p-ERK and ERK protein expression. Protein samples were extracted from liver tissue homogenates and analyzed by western blot. Effects of BAI on APAP-induced p-P38, P38, p-JNK, JNK, p-ERK and ERK in liver and statistical analysis of p-P38, P38, p-JNK, JNK, JNK and ERK protein expression (A–C). Control, APAP group; 50 mg/kg, 100 mg/mg BAI group; All data are expressed as mean ± S.D. n = 3. * p < 0.05, ** p < 0.01 compared with the model group; ^## p <0.01, ^# p <0.05 compared with control group.

Figure 9

Effects of BAI on p-JAK, JAK, p-STAT3and STAT3 protein expression. Protein samples were extracted from liver tissue homogenates and analyzed by western blot. Effects of BAI on APAP-induced p-JAK2, JAK2, p-STAT3 and STAT3 in liver and statistical analysis of p-JAK2, JAK2, p-STAT3and STAT3 protein expression (A,B).Control, APAP group; 50 mg/kg, 100 mg/mg BAI group; All data are expressed as mean ± S.D. n = 3., ** p < 0.01, * p < 0.05 compared with model group; ^## p < 0.01, ^# p < 0.05compared with control group.