[Protective effect of 2,4-dihydroxybenzophenone on cocaine-induced hepatotoxicity and neurotoxicity in mice].

OBJECTIVE: To investigate the protective effect of 2,4-dihydroxybenzophenone(BP-1) on acute hepatotoxicity and neurotoxicity induced by cocaine in mice, and its possible mechanism. METHODS: Male ICR mice were pretreated with BP-1(100,200,400 mg/kg, ig, 4 d), cocaine(75 mg/kg) was injected 30 minutes after BP-1 administration on day 4.Twenty-four hours after the injection of cocaine, the serum activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were assayed by HITACHI-7170A automatic analyzer. The content of malondialdehyde (MDA) and the content of reduced glutathione (GSH) and oxidized glutathione (GSSG) were examined, and the ratio of GSH/GSSG was calculated, and histopathological analyses were also made. Male ICR mice were pretreated with BP-1(100,200,400 mg/kg, ig, 3 d), cocaine(20 mg/kg) was injected 30 minutes after BP-1 administration on day 3.The locomotor activity during 0-180 minutes of mice was recorded individually for each animal immediately after cocaine injection. RESULTS: After the administration of cocaine, compared with corresponding solvent group, the activities of ALT [(1 571±1 161) IU/L vs. (30±16) IU/L, P<0.05], AST [(408±226) IU/L vs. (101±12) IU/L, P<0.05] and LDH [(3 963±1 431) IU/L vs. (1 935±287) IU/L, P<0.05] were significantly increased; the ratio of GSH/GSSG [(5.11±0.63) vs. (6.88±1.13),P<0.05] was decreased and the content of MDA [(1.97±1.36) µ mol/g vs. (0.07±0.06) µmol/g, P<0.01] was significantly increased. With the pretreatment of BP-1, compared with cocaine treatment group, the serum ALT [(112±96 )IU/L, (54±20) IU/L, (35±15) IU/L, P<0.05],AST [(130±33) IU/L,(107±5) IU/L, (99±9) IU/L, P<0.05] and LDH [(1 667±564) IU/L, (1 507±365) IU/L, (1 249±349) IU/L, P<0.01] were significantly decreased, the ratios of GSH/GSSG [(7.33±1.84), (9.28±0.67), (10.5±1.20), P<0.05] were increased and the contents of MDA [(1.82±1.19)µmol/g, (0.49±0.31)µmol/g, (0.35±0.30) µmol/g, P<0.05] were decreased. Significant amelioration in liver histopathology was also presented in the BP-1 treatment groups. The BP-1 pretreated mice showed significant reduction in activity counts evoked by cocaine (20 mg/kg), and shorten the time for activity counts to become normal. CONCLUSION: BP-1 has protective effect on acute hepatotoxicity and neurotoxicity of mice induced by cocaine. Its mechanisms might be associated with its antioxidant activity.

Protective effects of 5-methoxypsoralen against acetaminophen-induced hepatotoxicity in mice.

AIM: To investigate the hepatic protective effects of 5-methoxypsoralen (5-MOP) and to learn if 5-MOP causes hepatotoxicity at protective doses. METHODS: C57BL/6J mice were administrated orally with 5-MOP at doses of 12.5, 25 and 50 mg/kg body weight respectively every morning for 4 d before given acetaminophen (APAP) subcutaneously at a dose of 500 mg/kg. The 5-MOP alone group was treated with 5-MOP orally at a dose of 50 mg/kg body weight for 4 d without APAP. Twenty-four hours after APAP administration, blood samples of mice were analyzed for serum enzyme alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH) levels, and malondialdehyde (MDA), reduced glutathione (GSH) and oxidized glutathione (GSSG) of liver tissues were measured and histopathologic changes of the liver were observed. RESULTS: Compared with the vehicle control group, the serum levels (IU/L) of ALT, AST and LDH were all increased significantly in APAP group (8355 ± 3940 vs 30 ± 21, P < 0.05; 6482 ± 4018 vs 146 ± 58, P < 0.05; 24627 ± 10975 vs 1504 ± 410, P < 0.05). Compared with APAP group, the serum ALT levels (IU/L) (1674 ± 1810 vs 8355 ± 3940, P < 0.05; 54 ± 39 vs 8355 ± 3940, P < 0.05; 19 ± 9 vs 8355 ± 3940, P < 0.05), AST levels (IU/L) (729 ± 685 vs 6482 ± 4108, P < 0.05; 187 ± 149 vs 6482 ± 4108, P < 0.05; 141 ± 12 vs 6482 ± 4108, P < 0.05) and LDH levels (IU/L) (7220 ± 6317 vs 24 627 ± 10 975, P < 0.05; 1618 ± 719 vs 24 627 ± 10 975, P < 0.05; 1394 ± 469 vs 24 627 ± 10 975, P < 0.05) were all decreased drastically in the three-dosage 5-MOP pretreatment groups. Pretreatment of 5-MOP could attenuate histopathologic changes induced by APAP, including hepatocellular necrosis and infiltration of inflammatory cells, and the effect was dose-dependent. MDA levels (nmol/mg) were decreased by 5-MOP in a dose-dependent manner (0.98 ± 0.45 vs 2.15 ± 1.07, P > 0.05; 0.59 ± 0.07 vs 2.15 ± 1.07, P < 0.05; 0.47 ± 0.06 vs 2.15 ± 1.07, P < 0.05). The pretreatment of 5-MOP could also increase the GSH/GSSG ratio (3.834 ± 0.340 vs 3.306 ± 0.282, P > 0.05; 5.330 ± 0.421 vs 3.306 ± 0.282, P < 0.05; 6.180 ± 0.212 vs 3.306 ± 0.282, P < 0.05). In the group treated with 5-MOP but without APAP, the serum enzyme levels, the liver histopathologic manifestation, and the values of MDA and GSH/GSSG ratio were all normal. CONCLUSION: 5-MOP can effectively protect C57BL/6J mice from APAP-induced hepatotoxicity and possesses an antioxidative activity, and does not cause liver injury at the protective doses.

Protective effects of 2,4-dihydroxybenzophenone against acetaminophen-induced hepatotoxicity in mice.

AIM: To examine the effects of 2,4-dihydroxybenzophenone (BP-1), a benzophenone derivative used as an ultraviolet light absorbent, on acetaminophen (APAP)-induced hepatotoxicity in C57BL/6J mice. METHODS: Mice were administered orally with BP-1 at doses of 200, 400 and 800 mg/kg body weight respectively every morning for 4 d before a hepatotoxic dose of APAP (350 mg/kg body weight) was given subcutaneously. Twenty four hours after APAP intoxication, the serum enzyme including serum alaine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) were measured and liver histopathologic changes were examined. RESULTS: BP-1 administration dramatically reduced serum ALT, AST and LDH levels. Liver histopathological examination showed that BP-1 administration antagonized APAP-induced liver pathological damage in a dose-dependent manner. Further tests showed that APAP-induced hepatic lipid peroxidation was reduced significantly by BP-1 pretreatment, and glutathione depletion was ameliorated obviously. CONCLUSION: BP-1 can effectively protect C57BL/6J mice from APAP-induced hepatotoxicity, and reduction of oxidative stress might be part of the protection mechanism.

Longitudinal study to assess the safety and efficacy of a live-attenuated SHIV vaccine in long term immunized rhesus macaques.

Live-attenuated viruses derived from SIV and SHIV have provided the most consistent protection against challenge with pathogenic viruses, but concerns regarding their long-term safety and efficacy have hampered their clinical usefulness. We report a longitudinal study in which we evaluated the long-term safety and efficacy of DeltavpuSHIV(PPC), a live virus vaccine derived from SHIV(PPC). Macaques were administered two inoculations of DeltavpuSHIV(PPC), three years apart, and followed for eight years. None of the five vaccinated macaques developed an AIDS-like disease from the vaccine. At eight years, macaques were challenged with pathogenic SIV and SHIV. None of the four macaques with detectable cellular-mediated immunity prior to challenge had detectable viral RNA in the plasma. This study demonstrates that multiple inoculations of a live vaccine virus can be used safely and can significantly extend the efficacy of the vaccine, as compared to a single inoculation, which is efficacious for approximately three years.

[The hepatoprotective effect of aqueous extracts from Ficus hirta on N, N-dimethylformamide induced acute liver injury in mice].

OBJECTIVE: To investigate the effect of aqueous extract from Ficus hirta on N, N-Dimethylformamide (DMF) induced liver injury in mice. METHODS: C57BL/6 mice and ICR mice were randomly divided into 5 groups: negative control group, positive control group and three treated groups respectively. Treated groups were administered orally with 100, 200, 300 g/kg Ficus hirta aqueous extract per day respectively for 5 days. On the 4th day, 2. 3 g/kg DMF was given by intraperitoneal injection to all C57BL/6 mice except negative control group, while for ICR, DMF was administration at a 2.75 g/kg dose. 48h after DMF injection, serum samples were collected to determine the activities of ALT, AST and LDH and the pathological changes of liver tissue were analyzed under microscope. RESULTS: Compared with the positive control, the activities of ALT, AST and LDH were significantly reduced and the liver injury obviously attenuated in treated groups. CONCLUSION: The aqueous extract of Ficus hirta has an obvious protective effect against DMF-induced acute liver injury in mice.

[Effect of roots of Ficus hirta on cocaine-induced hepatotoxicity and active components].

OBJECTIVE: To investigate the protective effect of the roots of F. hirta against the cocaine-induced hepatotoxicity and it's active components. METHOD: Cocaine hydrochloride was subcutaneously injected to make male ICR mice liver wounded. Male ICR mice were randomly ig administered with the F. hirta decoction. The dose groups are 100, 200, 300 g x kg(-1) herb materials per body weight. Cocaine hydrochloride was subcutaneously injected into the mice after the administration. The serum ALT, AST activity and the activity of CAT in liver homogenate were assayed, and liver change of pathomorphism was evaluated to prove the effect of the F. hirta decoction on cocaine-induced hepatotoxicity. And the activity of psoralean which was separated from the F. hirta decoction by bioassay-guided fractionation, was proofed in the same method. RESULT: We find that the F. hirta decoction shows a distinct effect on reducing serum transferase. The serum transferase and the content CAT in liver homogenate were dose-related reduced, and the histopathological examination found a significantly change of the liver tissues. And the psoralean, qua the mainly component, shows the same effect. CONCLUSION: F. hirta has the protective effect against the cocaine-induced hepatotoxicity. Psoralean is the basis.

A noninfectious simian/human immunodeficiency virus DNA vaccine that protects macaques against AIDS.

Simian/human immunodeficiency virus SHIV(KU2) replicates with extremely high titers in macaques. In order to determine whether the DNA of the viral genome could be used as a vaccine if the DNA were rendered noninfectious, we deleted the reverse transcriptase gene from SHIVKU2 and inserted this DNA (DeltartSHIVKU2) into a plasmid that was then used to test gene expression and immunogenicity. Transfection of Jurkat and human embryonic kidney epithelial (HEK 293) cells with the DNA resulted in production of all of the major viral proteins and their precursors and transient export of a large quantity of the Gag p27 into the supernatant fluid. As expected, no infectious virus was produced in these cultures. Four macaques were injected intradermally with 2 mg of the DNA at 0, 8, and 18 weeks. The animals developed neutralizing antibodies and low enzyme-linked immunospot assay (E-SPOT) titers against SHIVKU2. These four animals and two unvaccinated control animals were then challenged with heterologous SHIV89.6P administered into their rectums. The two control animals developed viral RNA titers exceeding 10(6) copies/ml of plasma, and these titers were accompanied by the loss of CD4+ T cells by 2 weeks after challenge. The two control animals died at weeks 8 and 16, respectively. All four of the immunized animals became infected with the challenge virus but developed lower titers of viral RNA in plasma than the control animals, and the titers decreased over time in three of the four macaques. The fourth animal remained viremic and died at week 47. Whereas the control animals failed to develop E-SPOT responses, all four of the immunized animals developed anamnestic E-SPOT responses after challenge. The animal that died developed the highest E-SPOT response and was the only one that produced neutralizing antibodies against the challenge virus. These results established that noninfectious DNA of pathogenic SHIV could be used as a vaccine to prevent AIDS, even though the immunological assays used did not predict the manner in which the challenge virus would replicate in the vaccinated animals.

Protection against late-onset AIDS in macaques prophylactically immunized with a live simian HIV vaccine was dependent on persistence of the vaccine virus.

This is a 5-year follow-up study on 12 macaques that were immunized orally with two live SHIV vaccines, six with V1 and six with V2. All 12 macaques became persistently infected after transient replication of the vaccine viruses; all were challenged vaginally 6 mo later with homologous pathogenic SHIV(KU-1). Two of the V1 group developed full-blown AIDS without evidence of vaccine virus DNA in tissues. The data on the 10 vaccinated survivors showed that all 10 became infected with SHIV(KU-1) and that DNA of both vaccine and SHIV(KU-1) viruses were present 6 mo postchallenge, with minimal replication of SHIV(KU-1). During the following 5 years, these animals remained persistently infected, but with only one of the two viruses. Six animals eliminated their vaccine virus after variable periods of time and four of these succumbed to reactivation of the challenge virus and AIDS. Five years after challenge, four latently infected animals, two with V2 and two with SHIV(KU-1), were reinoculated with SHIV(KU-1.) This resulted in transient superinfection and the animals promptly returned to their prechallenge status. Immunosuppression of the four animals 1 year later with Abs to CD8+ lymphocytes resulted in transiently productive replication of their respective latent viruses, and upon recovery of CD8+ lymphocytes, they reverted to their latent virus status. The major finding was that of eight animals that eliminated the vaccine virus, six developed AIDS. The two others harboring SHIV(KU-1) remain at risk for developing late-onset disease. The primary correlate against AIDS was persistence of the vaccine virus.

Systemic infection and limited replication of SHIV vaccine virus in brains of macaques inoculated intracerebrally with infectious viral DNA.

SHIV deleted in two accessory genes, DeltavpuDeltanef SHIV(PPC), functioned well as a vaccine against later challenge with highly pathogenic SHIV(KU), and it was able to reach the brain after oral inoculation of live virus. In this study, the proviral genome cloned into a plasmid was inoculated as DNA intracerebrally and spread systemically. Few regions of the brain had detectable proviral DNA by real-time PCR. Two measures of virus replication, detection of viral mRNA expression and circular proviral DNA, were negative for those brain regions, with the exception of the infection site in the right parietal lobe, whereas lymphoid tissues were positive by both measures. Histopathological analyses of all the sampled brain and spinal cord regions did not reveal any abnormalities. Despite intracerebral inoculation of the viral DNA, the brain was not targeted for high levels of virus replication.

[Effect of 7,12-dimethylbenz(a)athrancene on immune function in metallothionein gene-knocked-out mice].

OBJECTIVE: To study the immunotoxicity induced by 9,10-dimethyl-1,2-benzathrancene (DMBA) in metallothionein gene-knocked-out mice [MT(-/-)] as compared with that in wild-type mice [(MT(+/+)]. METHODS: Female mice were treated with 25 mg/kg and 50 mg/kg of DMBA i.p., respectively and immunized with sheep red blood cells (SRBC) i.v. on the following day and rechallenged by injection of SRBC via footpad s.c. on the fourth day post-immunization. Humoral and cell-mediated immune function was assessed by the number of spleen IgM antibody plaque formation cells (PFC) to SRBC and cell-mediated delayed-type hypersensitivity (DTH) measured by footpad swelling thickness. RESULTS: After treatment with 25 mg/kg DMBA, a decrease in weight of their spleen and thymus and PFC/spleen were observed in MT(-/-) mice, while only decrease in thymus weight of MT(+/+) mice. The humoral function was suppressed by 72% in MT(-/-) mice. No obvious change in cell-mediated immune function was observed both in MT(-/-) and MT(+/+) mice. Both humoral and cell-mediated immune function were suppressed more severe (91%) in MT(-/-) mice treated with 50 mg/kg DMBA than those treated with 25 mg/kg DMBA (72%). DTH was not altered by DMBA in MT(+/+) mice. The weight of their spleen and thymus decreased and humoral immune function suppressed in MT(+/+) mice, but these changes were significantly less severe. No obvious suppression of cell-mediated immune function was observed in MT(+/+) mice. CONCLUSION: Their humoral and cell-mediated immune function was more susceptible to being suppressed by DMBA in MT(-/-) mice, indicating that MT could protect their immune function from damage caused by DMBA.