Effects Of Ganoderma Lucidum Polysaccharide On DEN-induced Mice Liver Tissue Morphology And The MRNA Expression Of The Original Proto-oncogene And Tumor Suppressor Genes

[Objective] To explore the anticancer molecular mechanism of Ganoderma lucidum polysaccharide, the effects of Ganoderma lucidum polysaccharide on DEN-induced mice liver tissue morphology and the mRNA expression of the proto-oncogene and tumor suppressor genes were investigated.[Methods](1) Antioxidant activity of Ganoderma lucidum Polysaccharide is determined by measuring the total reducing power, the scavenging capacity of DPPH-, superoxide anion radical (O2) and hydroxyl radical (-OH).(2)60healthy30d Kunming mice were randomly divided into six groups (female:male=1:1), and named as control group, DEN (Diethylnitrosamine) modal group, polysaccharide group, low dose group (DEN+50mg/kgd polysaccharide), middle dose group (DEN+100mg/kg-d polysaccharide) and high dose group (DEN+200mg/kg-d polysaccharide). The DEN modal group and DEN+polysaccharide group gave100mg/kg Diethylnitrosamine water for free drink. After45days, the liver samples were collected, observed liver tissue morphology with HE stain, and the mRNA expressions of the proto-oncogene such as ras、H-myc and tumor suppressor genes such as p53、Rb1with fluorescent quantitative real-time polymerase chain reaction (real-time RT-PCR).[Results](1) Polysaccharide from Ganoderma lucidum exhibited antioxidant activities. When the concentration of polysaccharide was2mg/mL, absorbance of reducing power was1.237, scavenging activities towards DPPH-, O2-,-OH and H2O2were89.3%,43.99%,89%,94.32%respectively.(2) Mice liver cells arranged radially in neat rows around the central static in control group and polysaccharide group. It can be seen cytoplasm with eosin stained red evenly and oval-shaped clearly dyed blue with ematoxylin. While in DEN group mice liver cells arranged in disorder, and some liver cells were swelling, or even burst. There were a considerable number of nuclear fragmentation, even vacuoles in cytoplasm, and a tiny pink protein particles (granular degeneration of liver). Due to swelling of the liver cells and narrowed liver sinus, local liver tissue caused ischemia. Compared with DEN group, with the dosage of Ganoderma lucidum polysaccharide increasing in test group, the degree of liver demage in mice alleviated.(3) Compared with the control group, the mRNA expression levels of H-ras, myc decreased in polysaccharide group were no significant difference; The mRNA expression levels of H-ras, myc were up-regulated by83.2%,52.4%respectively in DEN modal group, they were significantly different (p<0.05or p<0.01). Compared with DEN modal group, the mRNA expressed levels of H-ras, myc in test group were gradually decreased at0.01level with polysaccharide increased, the express levels were reduced by36.3%、31.2%in low dose group, by45.9%、40.1%in middle dose group and by50.6%、41.8%in high dose group.(4) Compared with the control group, the mRNA expression levels of Rbl,p53up-regulated by23.7%,14.5%in polysaccharide group, they were significantly different (p<0.05or p<0.01); The mRNA expression levels of Rb1、p53were increased by11.6%、9.7%in DEN modal group at0.05level. Compared with DEN modal group, the mRNA expressed levels of Rb1、p53in test group were increased gradually with Polysaccharide increased, the express levels were reduced by5.7%、9.6%in low dose group, by9.0%、24.1%in middle dose group and by14.6%、43.4%in high dose group,they were different (p<0.05or p<0.01).[conclusion] Polysaccharide from Ganoderma lucidum exhibited antioxidant activities, alleviated the damage of liver which was caused by DEN,inhibited the the expression of proto-oncogene and improved the expression of tumor suppressor genes.lt showed that Ganoderma lucidum polysaccharide can inhibit the occurrence or development of cancer through regulation of proto-oncogenes and tumor suppressor genes to some extent.