[Protective effect of Dendrobium officinale polysaccharide against α-amanitin-induced liver injury in mice based on Bax/Apaf-1/ Caspase-3 apoptosis pathway].

OBJECTIVE: To investigate the protective effect of Dendrobium officinale polysaccharides(DOP) on α-amatoxins-induced liver injury in mice and to analyze its regulatory role in the Bax/Apaf-1/Caspase-3 apoptosis signaling pathway.

METHODS: Sixty SPF-grade Kunming mice, half male and half female, were randomly divided into six groups according to sex and body weight: control group, α-amatoxins model group, and DOP intervention groups at doses of 20, 40, 80 and 160 mg/kg. Mice were administered α-amatoxins 0.6 mg/kg by gavage to induce acute liver injury. Immediately after administration, mice in each intervention group were administered the corresponding concentration of Dendrobium officinale polysaccharide solution by gavage at 6-h intervals for a total of four times. The control group and model group were simultaneously given an equal volume(10 mL/kg) of physiological saline. Mice were sacrificed 24 hours after exposure to the toxin, and blood and liver were collected. Serum alanine aminotransferase(ALT), aspartate aminotransferase(AST), total bilirubin(TBIL), alkaline phosphatase(ALP), and gamma-glutamyltransferase(GGT) levels were measured. Hematoxylin-eosin(HE) staining was used to observe histopathological changes in liver tissue. Real-time quantitative PCR and Western blot were used to detect the expression levels of Bax, Apaf-1, and Caspase-3 mRNA and protein in the liver. The content of reactive oxygen species in the liver was detected by fluorescent probe method. The levels of Bcl-2, cytochrome C, and Caspase-9 in the liver were measured by ELISA.

RESULTS: Compared with the control group, the α-amanita peptide model group showed significantly increased serum ALT, AST, TBIL, ALP and GGT levels, as well as significantly increased liver Bax, Apaf-1, and Caspase-3 mRNA and protein levels, and significantly increased liver reactive oxygen species, cytochrome C and Caspase-9 levels(P<0.05), and significantly decreased liver Bcl-2 levels(P<0.05). After DOP intervention, the serum ALT, AST, TBIL, ALP and GGT levels, as well as the liver Bax, Apaf-1, and Caspase-3 mRNA and protein levels, and significantly decreased liver reactive oxygen species, cytochrome C, and Caspase-9 levels in all groups of mice(P<0.05), and significantly increased liver Bcl-2 levels(P<0.05), and a clear dose-response relationship was observed with increasing DOP dosage(P<0.05). HE staining result showed that the livers of mice in the α-amanita peptide model group exhibited significant hepatocyte edema, necrosis, central venous congestion, and inflammatory cell infiltration. Hepatocyte morphology was disordered, with nuclear pyknosis, fragmentation, and dissolution; some areas showed loss of lobular structure, and the necrotic area was expanded. Different doses of DOP intervention groups showed improvement in liver pathological changes. Especially in the DOP 160 mg/kg group, hepatocyte edema and necrosis were significantly reduced, the congestion and necrosis area around the central vein was significantly reduced, and the extent of inflammatory cell infiltration was also significantly decreased.

CONCLUSION: DOP has a significant protective effect against α-amanita peptide-induced liver injury in mice. It improves liver function and histopathological manifestations by inhibiting the Bax/Apaf-1/Caspase-3 signaling pathway, reducing oxidative stress and hepatocyte apoptosis.