Objective To study the regulation of natural polyamines(putrescine,spermidine and spermine) on ornithine decarboxylase gene transcription in regenerating rat hepatocytes and to assess the roles of polyamines in liver regeneration. Methods Rat regenerating liver was induced by surgical partial hepatectomy(PH).The expressive levels of ODC mRNA in regenerating liver were measured by in situ hybridization analysis.Exogenous polyamines(dissolved in 0.9% NaCl) were administered subcutaneously to adult male Sprague-Dawley rats. Results ODC mRNA expression was always lower in high dose(20 mg/kg body weight) putrescine-treated rats compared with that in control rats during the observed regeneration,especially at the 2(nd),4(th) and 10(th) hours(P

Objective To study the role of polyamines(putrescine,spermidine and spermine) in regulating ornithine decarboxylase(ODC) protein levels in the early regenerating liver of rats. Methods Exogenous polyamines(dissolved in 0.9% NaCl) were administered subcutaneously to adult male SD rats(180～220g).The ODC protein levels in the regenerating liver induced by partial hepatectomy(PH) were measured by Western blotting analysis. Results The treatment with high doses of putrescine( 20 mg/kg body weight),spermidine(0.15 mg/kg body weight) or spermine(6 mg/kg body weight) reduced the ODC protein level compared with the control group within 12 hours after PH.However,the treatment with low doses of putrescine(0.02 mg/kg),spermidine(0.03 mg/kg) or spermine(0.06 mg/kg) resulted in a rapid increase in the protein level in the 4th hour after PH,which was 15.1%,29.5% or 30.3% higher than that of control rats respectively.Conclusion Polyamines with certain doses play a role in the feedback regulation of ODC protein levels in the early regenerating liver,where spermidine and spermine play a greater role than putrescine dose.

Objective The regulation of ornithine decarboxylase (ODC) gene expression and enzyme activity by corticosterone, the main glucocorticoid in rat, during rat liver regeneration induced by partial hepatectomy (PH) was evaluated.Methods Bilateral adrenaleetomies (ADX) and sham-ADX were performed on ether-anesthetized rats 3 days before PH.Corticosterone in sesame oil was injected subcutaneously to adrenalectomied rats. ODC mRNA, ODC protein and enzyme activity were detected by RT-PCR, Western blotting and high performance liquid chromatography (HPLC), respectively. Results The ODC mRNA levels, protein accumulation and enzyme activity were lower in the intact liver compared to the regenerating liver.After PH, mRNA levels were remarkably enhanced in all groups (n=6 in each group) and peaked at 5 hours post-PH. Till 7 hours, the contents in all groups from high to low were ADX group,control group (Sham-ADX group), ADX treated with 10mg/kg and 40mg/kg body weight corticosterone group, respectively. ODC protein accumulation in ADX rats was higher than that in control rats (n=13, the same below), but it decreasod in corticosterone-treated (10mg/kg) rats until 24 hours post-PH, with a strong decline seen in 40mg/kg corticosterone-treated rats. ODC activity was rapidly promoted, and the highest levels were observed at 6 hours after PH in all groups (n=6 in each group). After corticosterone treatment, the activities declined significantly at 6 hours post-PH, with the lowest value found in the 40mg/kg group. Conclusion Corticosterone treatment results in dose-dependent decreases in ODC mRNA and enzyme protein both in the intact liver and the regenerating liver. The change in ODC activity is partially related to alterations of ODC mRNA and protein accumulation.

Objective To research the effect of exogenous estradiol(E-2) on transcriptional activity of regenerating hepatocytes in rats. Methods The E-2 levels in serum were measured using RIA and the numbers of argyrophil nucleolar organizer regions(AgNORs) were investigated. Results Rat serum E-2 level gradually declined after ovariectomy,and no E-2 could be measured after the 15th day.Exogenous E-2 could promote transcriptional activity of regenerating rat hepatocytes,particularly during the first 24h after PH,there was a dose-dependent increase in numbers of AgNORs 24-36h after PH,the exogenous E-2 cause a dose-dependent decrease in numbers of AgNORs,but all of the values were higher than that of control group.Conclusion E-2 can regulate the transcriptional activity of regenerating hepatocytes in rats.

Objective:Selected virulence factors more than and high virulent Aeromonas hydrophia strain made into inactivated vaccine,to study the immunization effect of inactivated vaccine.Methods:Crucian were vaccinated with formalin-killed vaccine via in-traperitoneal injection.Controls were injected with the same volumes of saline.Then the antibody titres, histopathology and relative percent survival were analyzed from samples of both groups.Results: The antibody in the indirect agglutination reaction could be detected in vaccinated fish once a weeks after immunization and reached highest level 6 weeks after immunization.The histopathology analysis indicated that the vaccine had a good protective effect on crucian target organs.Vaccinated fish showed 100%relative percent survival and the immune period would be 6 month.Conclusion:The vaccine in this study has a significant protective effect on crucian and may be used as effective fish vaccines against bacterial septicemia.