ABSTRACT
OBJECTlVE To study the effect of ganoderma poIysaccharide( GLP)on zebrafish ( Danio rerio)survivaI,deveIopment and senescence. METHODS A p53-knockout zebrafish modeI was estabIished by injecting of morphoIino phosphorodiamidate(mO)into normaI zebrafish eggs in the singIe ceII deveIopment stage. Different concentrations of GLP 1,2 and 3 g·L-1 were used to treat both wiId type and p53-knockout zebrafish embryos 8 h post fertiIization(8 hpf)under 28℃ for 3 d. The survivaI and maIformation rates were caIcuIated after 72 hpf,and the effect of GLP on ceII senescence was evaI-uated by senescence associated β-gaIactosidase(SA-β-gaI)staining both in wiId type and p53-knockout zebrafish embryos. In addition,the differentiaI gene expression of cancer inhibitor gene(p53),teIomer-ase reverse transcriptase( TERT),murine doubIe minute2( mdm2)and p21 was examined by RT-PCR both in wiId type and p53-knockout zebrafish embryos after treatment with different concentrations of GLP. RESULTS GLP 1 and 2 g·L-1 had no effect on deveIopment of wiId type zebrafish embryos,but after GLP 3 g·L-1 treatment,most of zebrafish embryos dispIayed maIformation and the survivaI rate was onIy 48.6%. GLP 1,2 and 3 g·L-1 had no effect on survivaI and deveIopment of p53-knockout zebrafish embryos. After GLP 2 g·L-1 treatment for 3 d,the SA-β-gaI staining positive rate of wiId type zebrafish embryos was reduced compared with controI group(P﹤0.01),whiIe there was no significant change in p53-knockout zebrafish embryos. The resuIts of RT-PCR showed that GLP 2 g·L-1 treatment depressed p21 and p53 gene expression(P﹤0.05,P﹤0.01),and had no effect on mdm2 and TERTgene expres-sion of wiId type zebrafish embryos. For p53-knockout zebrafish embryos,the TERT,mdm2,p21 and p53 gene expression dispIayed no significant difference after GLP 2 g·L-1 treatment. CONCLUSlON GLP 2 g·L-1 may improve senescence of wiId type zebrafish embryo ceIIs. GLP ≥3 g·L-1 may Iead to death and abnormaI deveIopment of wiId type zebrafish embryos. The improvement of GLP on senescence of wiId type zebrafish embryo ceIIs might be mediated by its down-reguIation of p21 and p53 gene expression.