Iron deposition and fat accumulation in dimethylnitrosamine-induced liver fibrosis in rat

AIM： To investigate if iron deposition and fat accumulation in the liver play a pathogenetic role in dimethylnitrosamine （DMN）-induced liver fibrosis in rat.METHODS： Thirty rats were treated with DMN at does consecutive days of 10 μL/kg daily, i.p., for 3 consecutive day each week for 4 wk. Rats （n = 30） were sacrificed on the first day （model group A） and 21st d （model group B） after cessation of DMN injection. The control group （n = 10） received an equivalent amount of saline. Liver tissues were stained with hematoxylin ＆ eosin （HE） and Masson and Prussian blue assay and oberserved under electron microscopy. Serum alanine aminotransferase （ALT）and liver tissue hydroxyproline （Hyp） content were tested.RESULTS： The liver fibrosis did not automaticallyreverse, which was similar to previous reports, the perilobular deposition of iron accompanied with collagen showed marked characteristics at both the first and 21st d after cessation of DMN injection. However, fat accumulation in hepatocytes occurred only at the 21^st d after cessation of DMN injection.CONCLUSION： Iron deposition and fat accumulation may play important roles in pathological changes in DMN-induced rat liver fibrosis. The detailed mechanisms of these characteristics need further research.

Mutations outside the YMDD motif in the P protein can also cause DHBV resistant to Lamivudine

AIM: To observe the Lamivudine resistance character of a DHBV strain in vitro and in vivo, and to analyze if the Lamivudine resistance character is caused by gene mutation or by abnormity of the Lamivudine metabolism.METHODS: Congenitally DHBV-negative Guangdong brown ducks and duck embryo liver cells were respectively taken as animal and cell model. The Lamivudine-susceptive DHBV and Lamivudine-resistant DHBV (LRDHBV) were infected and Lamivudine was administrated according to the divided groups. The changes of DHBV quantity in the animal and cell model were tested. Three Lamivudineresistant and two Lamivudine-susceptive DHBV complete genomes were successfully amplified, sequenced and then submitted to GenBank. All the DHBV complete sequences in the GenBank at present were taken to align with the three LRDHBV to analyze the mutational points related to the Lamivudine-resistant mutation.RESULTS: Both the animal and cell model showed that the large and the small dosage Lamivudine have no significant inhibitory effect on the LRDHBV. Five sequences of DHBV complete genomes were successfully cloned. The GenBank accession numbers of the three sequences of LRDHBV are AY521226, AY521227, and AY433937. The two strains of Lamivudine-susceptive DHBV are AY392760and AY536371. The correlated mutational points are KorR86Q and AorE591T in the P protein.CONCLUSION: The Lamivudine resistance character of this DHBV strain is caused by genome mutation; the related mutational points are KorR86Q and AorE591T and have no relations with the YMDD motif mutation.