Curcumin protects against acetaminophen-induced apoptosis in hepatic injury

Abstract

Aim: To explore the effects of curcumin (CMN) on hepatic injury induced by acetaminophen (APAP) in vivo.

Methods: Male mice were randomly divided into three groups: group I (control) mice received the equivalent volumes of phosphate-buffered saline (PBS) intraperitoneally (ip); Group II [APAP + carboxymethylcellulose (CMC)] mice received 1% CMC (vehicle) 2 h before APAP injection; Group III (APAP + CMN) mice received curcumin (10 or 20 mg/kg, ip) 2 h before before or after APAP challenge. In Groups II and III, APAP was dissolved in pyrogen-free PBS and injected at a single dose of 300 mg/kg. CMN was dissolved in 1% CMC. Mice were sacrificed 16 h after the APAP injection to determine alanine aminotransferase (ALT) levels in serum and malondialdehyde (MDA) accumulation, superoxide dismutase (SOD) activity and hepatocyte apoptosis in liver tissues.

Results: Both pre- and post-treatment with curcumin resulted in a significant decrease in serum ALT compared with APAP treatment group (10 mg/kg: 801.46 ± 661.34 U/L; 20 mg/kg: 99.68 ± 86.48 U/L vs 5406.80 ± 1785.75 U/L, P < 0.001, respectively). The incidence of liver necrosis was significantly lowered in CMN treated animals. MDA contents were significantly reduced in 20 mg/kg CMN pretreatment group, but increased in APAP treated group (10.96 ± 0.87 nmol/mg protein vs 16.03 ± 2.58 nmol/mg protein, P < 0.05). The decrease of SOD activity in APAP treatment group and the increase of SOD in 20 mg/kg CMN pretreatment group were also detected (24.54 ± 4.95 U/mg protein vs 50.21 ± 1.93 U/mg protein, P < 0.05). Furthermore, CMN treatment efficiently protected against APAP-induced apoptosis via increasing Bcl-2/Bax ratio.

Conclusion: CMN has significant therapeutic potential in both APAP-induced hepatotoxicity and other types of liver diseases.

Keywords: Acetaminophen; Acute hepatic injury; Apoptosis; Curcumin; Free radicals.

Figure 1

Curcumin treatment protects against acetaminophen-induced hepatic injury in mice. A: Serum alanine aminotransferase (ALT) levels were determined 16 h after acetaminophen injection. Data are expressed as mean ± SE; n = 10 mice per group. ^bP < 0.01 vs control; ^dP < 0.001 vs acetaminophen (APAP) + carboxymethylcellulose (CMC); B: Hematoxylin-eosin stained liver sections from animals treated with PBS, APAP + CMC and APAP + CMN (original magnification: ×100 and ×400). Severe inflammatory cell infiltration and gross necrosis of the entire centrilobular areas were obvious in APAP group, and the results were significantly ameliorated in CMN-treated animals. CMN: Curcumin.

Figure 2

Curcumin pretreatment inhibits malondialdehyde production after acetaminophen induction. Liver homogenate was prepared to analyze the content of malondialdehyde (MDA) 16 h after acetaminophen (APAP) administration. Data are expressed as mean ± SE; n = 10 mice per group. ^aP < 0.05 vs control; ^cP < 0.05 vs APAP + curcumin (CMN). CMC: Carboxymethylcellulose.

Figure 3

Curcumin pretreatment enhances activity of superoxide dismutase after acetaminophen. Liver homogenate was prepared to analyze the activity of superoxide dismutase (SOD) 16 h after acetaminophen (APAP) administration. Data are expressed as mean ± SE; n = 10 mice per group. ^aP < 0.05 vs control; ^cP < 0.05 vs APAP + curcumin (CMN). CMC: Carboxymethylcellulose.

Figure 4

Curcumin pretreatment prevents hepatocyte apoptosis induced by acetaminophen. A: Transferase-mediated dUTP-biotin nick end labeling stained liver sections from animals treated with PBS, acetaminophen (APAP) + carboxymethylcellulose (CMC) and APAP + curcumin (CMN) (original magnification: × 400); B: Liver samples were collected 2 h and 16 h after APAP injection, and the mRNA expression of Bax and Bcl2 was determined by reverse transcriptase polymerase chain reaction. Data are expressed as mean ± SE; n = 6 mice per group. ^aP < 0.05 vs APAP + CMC.