Hepatoprotective effect of polysaccharides from Boschniakia rossica on carbon tetrachloride-induced toxicity in mice

Abstract

The purpose of this study was to investigate the protective effect of polysaccharides from Boschniakia rossica against hepatotoxicity induced by carbon tetrachloride (CCl4). Boschniakia rossica polysaccharides was administered intragastrically once daily for 7 days. One hour after the final treatment, mice were treated intraperitoneally with 80 mg/kg of CCl4. CCl4-induced hepatotoxicity was manifested by increased levels of serum marker enzymes and hepatic lipid peroxidation, and by decreased potential of hepatic antioxidative defense system. CCl4 challenge also resulted in elevated serum tumor necrosis factor-α and hepatic nitric oxide level, and up-regulation of inducible nitric oxide synthase and cyclooxygenase-2 proteins of liver tissue. Pretreatment of mice with Boschniakia rossica polysaccharides reversed these altered parameters of mice with liver injury induced by CCl4. Furthermore, caspase-3 cleavage and activities, and DNA fragmentation of liver in mice treated with Boschniakia rossica polysaccharides were decreased than mice treated with CCl4 alone. Hepatoprotective effect of Boschniakia rossica polysaccharides was further demonstrated by histopathological examination of liver sections. The results indicate that Boschniakia rossica polysaccharides play a protective role in CCl4-induced acute liver injury and the hepatoprotective effect of Boschniakia rossica polysaccharides may be due to elevated antioxidative defense potentials, suppressed inflammatory responses and apoptosis of liver tissue.

Keywords: Boschniakia rossica; carbon tetrachloride; hepatotoxicity; mice; polysaccharides.

Fig. 1

BRPS alleviated CCl₄-induced hepatotoxicity dose- and time-dependently. The animals were pretreated with BRPS, silymarin or a vehicle. Blood samples were harvested at 8 h, 16 h or 24 h after CCl₄ exposure on day 7, and the serum levels of ALT (A) and AST (B) were determined. In another set of animals, BRPS or silymarin were administered on a daily basis for 3 and 7 days, respectively. Blood samples were harvested at 16 h after CCl₄ exposure and the serum levels of ALT (C) and AST (D) were determined. ^#p<0.05, significantly different from group I; *p<0.05, significantly different from group II; ^†p<0.05, significantly different from group III. Group I: normal control; group II: model (CCl₄ alone); group III: CCl₄ plus BRPS (100 mg/kg); group IV: CCl₄ plus BRPS (200 mg/kg); group V: CCl₄ plus silymarin (50 mg/kg); group VI: BRPS (200 mg/kg) alone.

Fig. 2

BRPS improved liver histological alterations in CCl₄-challenged mice. Liver sections were stained with hematoxylin-eosin for morphological evaluation (×400). The animals were pretreated with BRPS, silymarin or a vehicle. CCl₄ was given i.p. on the 7th day of the treatment protocol, and the animals were sacrificed 16 h after CCl₄ administration. (A) Normal control; (B) CCl₄ model; (C) CCl₄ plus BRPS (100 mg/kg); (D) CCl₄ plus BRPS (200 mg/kg); (E) CCl₄ plus silymarin (50 mg/kg); (F) BRPS (200 mg/kg) alone.

Fig. 3

BRPS reduced serum ALP activities in CCl₄ exposed mice. Data are presented as mean ± SEM of ten mice per group. The animals were pretreated with BRPS, silymarin or a vehicle. CCl₄ was given i.p. on the 7th day of the treatment protocol, and the animals were sacrificed 16 h after CCl₄ administration. ^#p<0.05, significantly different from group I; *p<0.05, significantly different from group II. Group I: normal control; group II: model (CCl₄ alone); group III: CCl₄ plus BRPS (100 mg/kg); group IV: CCl₄ plus BRPS (200 mg/kg); group V: CCl₄ plus silymarin (50 mg/kg); group VI: BRPS (200 mg/kg) alone.

Fig. 4

BRPS reduced serum TNF-α contents in CCl₄ exposed mice. Data are presented as mean ± SEM of ten mice per group. The animals were pretreated with BRPS, silymarin or a vehicle. CCl₄ was given i.p. on the 7th day of the treatment protocol, and the animals were sacrificed 16 h after CCl₄ administration. ^#p<0.05, significantly different from group I; *p<0.05, significantly different from group II. Group I: normal control; group II: model (CCl₄ alone); group III: CCl₄ plus BRPS (100 mg/kg); group IV: CCl₄ plus BRPS (200 mg/kg); group V: CCl₄ plus silymarin (50 mg/kg); group VI: BRPS (200 mg/kg) alone.

Fig. 5

BRPS reduced hepatic TBARS contents in CCl₄ exposed mice. Data are presented as mean ± SEM of ten mice per group. The animals were pretreated with BRPS, silymarin or a vehicle. CCl₄ was given i.p. on the 7th day of the treatment protocol, and the animals were sacrificed 16 h after CCl₄ administration. ^#p<0.05, significantly different from group I; *p<0.05, significantly different from group II. Group I: normal control; group II: model (CCl₄ alone); group III: CCl₄ plus BRPS (100 mg/kg); group IV: CCl₄ plus BRPS (200 mg/kg); group V: CCl₄ plus silymarin (50 mg/kg); group VI: BRPS (200 mg/kg) alone.

Fig. 6

BRPS reduced hepatic NO contents in CCl₄ exposed mice. Data are presented as mean ± SEM of ten mice per group. The animals were pretreated with BRPS, silymarin or a vehicle. CCl₄ was given i.p. on the 7th day of the treatment protocol, and the animals were sacrificed 16 h after CCl₄ administration. ^#p<0.05, significantly different from group I; *p<0.05, significantly different from group II. Group I: normal control; group II: model (CCl₄ alone); group III: CCl₄ plus BRPS (100 mg/kg); group IV: CCl₄ plus BRPS (200 mg/kg); group V: CCl₄ plus silymarin (50 mg/kg); group VI: BRPS (200 mg/kg) alone.

Fig. 7

BRPS down-regulated hepatic iNOS and COX-2 protein expression in CCl₄ exposed mice. Data are presented as the means of six mice per group. The animals were pretreated with BRPS (200 mg/kg), silymarin (50 mg/kg) or a vehicle. CCl₄ was given i.p. on the 7th day of the treatment protocol, and the animals were sacrificed 16 h after CCl₄ administration. GAPDH was used as an internal control and the relative level of protein expression was normalized to the control.

Fig. 8

BRPS suppressed hepatic caspase-3 cleavage in CCl₄ exposed mice. Data are presented as the means of six mice per group. The animals were pretreated with BRPS (200 mg/kg), silymarin (50 mg/kg) or a vehicle. CCl₄ was given i.p. on the 7th day of the treatment protocol, and the animals were sacrificed 16 h after CCl₄ administration. GAPDH was used as an internal control and the relative level of protein expression was normalized to the control.

Fig. 9

BRPS reduced hepatic caspase-3 activities in CCl₄ exposed mice. Data are presented as mean ± SEM of ten mice per group. The animals were pretreated with BRPS, silymarin or a vehicle. CCl₄ was given i.p. on the 7th day of the treatment protocol, and the animals were sacrificed 16 h after CCl₄ administration. ^#p<0.05, significantly different from group I; *p<0.05, significantly different from group II. Group I: normal control; group II: model (CCl₄ alone); group III: CCl₄ plus BRPS (100 mg/kg); group IV: CCl₄ plus BRPS (200 mg/kg); group V: CCl₄ plus silymarin (50 mg/kg); group VI: BRPS (200 mg/kg) alone.

Fig. 10

BRPS suppressed hepatic DNA fragmentation in CCl₄ exposed mice. The animals were pretreated with BRPS (200 mg/kg), silymarin (50 mg/kg) or a vehicle. CCl₄ was given i.p. on the 7th day of the treatment protocol, and the animals were sacrificed 16 h after CCl₄ administration. Lane M: marker; Lane 1: normal control; Lane 2: model (CCl₄ alone); Lane 3: CCl₄ plus BRPS (200 mg/kg); Lane 4: CCl₄ plus silymarin (50 mg/kg); Lane 5: BRPS (200 mg/kg) alone.