A mouse model for studying the clearance of hepatitis B virus in vivo using a luciferase reporter.

Hepatitis B virus(HBV) infection remains a global problem, despite the effectiveness of the Hepatitis B vaccine in preventing infection. The resolution of Hepatitis B virus infection has been believed to be attributable to virus-specific immunity. In vivo direct evaluation of anti-HBV immunity in the liver is currently not possible. We have developed a new assay system that detects HBV clearance in the liver after the hydrodynamic transfer of a reporter gene and over-length, linear HBV DNA into hepatocytes, followed by bioluminescence imaging of the reporter gene (Fluc). We employed bioluminescence detection of luciferase expression in HBV-infected hepatocytes to measure the Hepatitis B core antigen (HBcAg)-specific immune responses directed against these infected hepatocytes. Only HBcAg-immunized, but not mock-treated, animals decreased the amounts of luciferase expression, HBsAg and viral DNA from the liver at day 28 after hydrodynamic infection with over-length HBV DNA, indicating that control of luciferase expression correlates with viral clearance from infected hepatocytes.

[The protective effect of high density lipoprotein on the lung function of rats with severe burns].

OBJECTIVE: To explore the protective effect of high density lipoprotein on the lung function of rats with severe burns. METHODS: One hundred and thirty-five Wistar rats were employed in the study and were randomly divided into control (n = 15, without injury), burn (n = 60, with 30% TBSA full-thickness burn on the back) and experimental [(n = 60, with the injection of HDL (80 mg/kg) via the caudal vein immediately after burns)] groups. The rats in the latter two groups were resuscitated with intraperitoneal isotonic saline (50 ml/kg) 30 minutes after burns. The serum content of ICAM-1 and TNF-alpha as well as the blood content of PCO2 and PO2 of the rats in burn and experimental groups were determined at 12, 24, 48 and 72 post-burn hours (PBH) and in control group. The pathological changes in the lung tissue of the rats in all groups were observed under light microscope and electronic microscope at 48 PBH. RESULTS: PCO2 and the contents of ICAM-1 and TNF-alpha in burn group were significantly higher, but the PO2 was lower than those in control group at each time-point (P < 0.05 or P < 0.01). There were no obvious differences in the above indices between the experimental and control groups (P > 0.05), but the ICAM-1 and TNF-alpha levels in experimental group were markedly decreased than those in burn group at each time-point (P < 0.05 or P < 0.01). The ICAM-1 and TNF-alpha contents in burn group at 48 PBH were (3.42 +/- 0.25) microg/L and (4. 04 +/- 0.28) ng/L, respectively, which were markedly higher than those in experimental group [(2.24 +/- 0.14) microg/L, (3.35 +/- 0.22) ng/L, P < 0.05 or P < 0.01]. Dilation of capillaries, congestion and inflammatory infiltration in the pulmonary capillaries, and loosening of conjunction between pulmonary capillary vascular endothelial cells and endothelial swelling were observed in burn group at 48 PBH. Compared with the burn group, the injury was markedly alleviated in the experiment group, and the pulmonary capillary endothelial cells showed tighter junction. CONCLUSION: HDL exhibits a protective effect on the lung function of rats with severe burns via reducing the expression of ICAM-1 and TNF-alpha.

[The protective effect of high density lipoprotein on the cardiac function of rats with severe burns].

OBJECTIVE: To investigate the protective effect of high density lipoprotein on the cardiac function of rats with severe burns. METHODS: One hundred and thirty-five Wistar rats were employed in the study and were randomly divided into control (n = 15, without treatment), burn (n = 60, with 30% TBSA full-thickness burn on the back) and experimental (n = 60, with the injection of HDL (80 mg/kg) via the caudal vein immediately after burns) groups. The rats in the groups with burn injury were resuscitated with intraperitoneal isotonic saline (50 ml/kg) 30 minutes after burn (PBM). The serum contents of CK, ICAM-1 and TNF-alpha of the rats of all the three groups were determined with corresponding methods. The histological changes in the cardiac muscle tissue of the rats in all groups were observed under light microscope and electronic microscope. RESULTS: The serum contents of CK, ICAM-1 and TNF-alpha in the control group were obviously lower than those in burn group (P < 0.01), while those in experimental group were also markedly lower than those in control group (P < 0.05 or 0.01). The average reduction rate was 36.5%, 32.0% and 12.6%, respectively. The size and the structure of the cardiac muscular fiber in the control group were even and normal. Compared with the burn group, degeneration, inflammatory infiltration and mitochondrial swelling were found to be less marked in the experimental group at 48 PBH, and no focal lysis and necrosis were found, which were observed in the burn group. CONCLUSION: High density lipoprotein can be beneficial to the protection of cardiac tissue in protecting from secondary injury in rats with severe burns.