| OBJECTIVETuberculosis (TB) is one of the major infectious diseases in our country. Due to the rebound of TB and the emergence of multi-drug resistant and extensively-drug resistant strains of Mycobacterium tuberculosis have complicated the tuberculosis situation, and lead to a longer treatment and an increasing quantity of anti-TB drugs. The rate of liver injury induced by anti-TB drugs is rising year by year, and liver injury induced by anti-TB drugs become one of the most common causes of drug-induced liver injury, in particular, isoniazid and rifampin induced liver damage are top two. Once there is an evidence of hepatotoxicity, the treatment of tuberculosis must be suspended and treatment of liver injury must be started. Therefore, it is very important to investigate what could inhibit the liver injury induced by RIF and INH.Garlic has been widely used in food and medicine with a long history. It has diverse biological activity including antibacterial. Especially recent years numerous studies have shown that garlic has antimycobacterial capacity against different species of mycobacteria. GO has been proved to offer protection against hepatotoxic compounds, such as acetaminophen induced liver injury. But whether or not garlic oil could inhibit the liver injury induced by RIF and INH has not been reported all around the world.Refer to some relevant articles, the animal model in the present study was induced by intragastric administration of the combination of RIF and INH. ALT, AST, ALP and TB in serum and histological changes of liver were evaluated to investigate whether garlic oil have the protective effect of the liver injury induced by the combination of RIF and INH. In order to investigate the mechanism of hepatic toxicity induced by the combination of RIF and INH and provide a scientific basis for further research and clinical application in the future, antioxidant system in both serum and liver were examined.METHODS1. Animal model Male Wistar rats, weighing180-200g were used in the experiments. They were obtained from Laboratory Animal Center of Shandong University. Animals were housed in the animal house under standard environmental conditions with standard diet and water ad libitum. All rats were acclimatized for a week before starting the experiments. All procedures were conducted in accordance with the National Institutes of Health Guidelines for Care and Use of Laboratory Animals and the principles in the "Use of Animals in Toxicology".Rats were randomly divided into5groups, control group (group1), RIF+INH model (group2), RIF+INH+low-dose GO20mg/kg (group3), RIF+INH+middle-dose GO40mg/kg (group4) and RIF+INH+high-dose GO80mg/kg (group5). Rats in control group were gavaged with5%starch solution; others were treated orally with150mg/kg of RIF and100mg/kg INH daily for28d. For garlic oil groups,20,40,80mg/kg per day of GO was administered orally2h before the RIF+INH doses. The rats of control group were given the same volume of corn oil. The changes of body weight were observed weekly. At the end of the experiment, rats were sacrificed by cervical decapitation. The livers and the serum were stored at-80℃. Ten percent homogenate was prepared before analyzing biochemical indexes. SOD, T-AOC, CAT, GSH-Px, GR, GST, MDA, GSH were estimated in both serum and homogenized liver tissues.Protein concentration was determined by using BCATM Protein assay Kit.2. Assessing of the protective effect of garlic oilALT, AST, ALP activities and TB in serum were measured by using kits. Livers were excised and washed with normal saline for biochemical analysis and histological tests. And the liver weights and organ coefficients of liver in rats were observed.3. Assessing of the influence of garlic oil on antioxidant systemTen percent homogenate was prepared before analyzing biochemical indexes. SOD, T-AOC, CAT, GSH-Px, GR, GST, MDA, GSH were estimated in both serum and homogenized liver tissues.Protein concentration was determined by using BCATM Protein assay Kit.4. Statistical analysisAll data are expressed as mean±S.D (n=12in each group). The results were analyzed by using analysis of variance (ANOVA) followed with LSD for the multiple comparisons in SPSS. The significance level was set at P<0.05. RESULTS1. Serum alanine aminotransferase, serum aspartate aminotransferase, alkaline phosphatase and serum total bilirubinWhen the model group was compared with the control group, serum ALT, AST, ALP and TB levels were significantly higher in the model group (P<0.05or P<0.01). Serum ALT, AST, ALP and TB levels were significantly lower in low, middle and high dose garlic oil groups when compared with the model group (P<0.05or P<0.01).2. Serum MDA and liver MDABoth serum and liver MDA levels in the model group were significantly higher than those of the control group (P<0.05). When compared to the model group, the serum MDA levels in low, middle and high dose garlic oil groups were decreased by2.91%,9.30%(P>0.05),20.35%(P<0.05), while the liver MDA were decreased (P<0.05).3. Serum and liver GSH levelsSerum and the liver GSH levels were significantly lower in the model group than in the control group (P<0.05). When compared to the model group, serum GSH levels in high dose garlic oil groups were significantly higher. The liver GSH levels were higher high dose garlic oil groups when compared to the model group (P<0.05).4. Serum and liver GST levels, serum and liver GSH-Px levels, serum and liver GRSerum GST levels were significantly lower in the model group than in the control group. The liver GST levels were lower in the model group than in the control group, but there was no statistically significant difference. When compared with the model group, serum GST levels were higher in low, middle and high dose garlic oil groups (P>0.05). The low, middle and high dose garlic oil groups showed a significant increase in liver GST levels when compared to the model group. When compared with the control group, serum and liver GSH-Px levels were significantly lower in the model group. When the model group was compared with middle and high dose garlic oil groups, GSH-Px levels were significantly higher in the middle and high dose garlic oil groups. There was no statistically significant difference in both the serum and liver GR levels in the model group when compared with the control group. When compared to the model group, the serum GR levels had increased in the low, middle and high dose garlic oil groups, while the liver GR levels were increased by 10.81%(P>0.05),18.92%(P>0.05),29.73%(P<0.05).5. Serum and liver SOD, serum and liver CAT levelsSerum and liver SOD levels in the model group were significantly lower than that in the control group. When compared to the model group, the serum SOD levels were significantly higher in the low, middle and high dose garlic oil groups. The SOD levels in liver were significantly higher in low, middle and high dose garlic oil groups compared with the model group.When compared to the control group, the serum and liver CAT levels in the model group were significantly lower (P<0.05). The serum CAT levels in the low, middle and high dose garlic oil groups had decreased by23.96%,19.26%,10.75%, but there was no statistically significant difference. The liver CAT levels in the low, middle and high dose garlic oil groups had significantly decreased by42.15%(P<0.05),32.31%(P<0.05),28.62%(P<0.05). When compared with the model group, the low, middle and high dose garlic oil groups had lower serum CAT levels. The serum CAT levels in the low, middle and high dose garlic oil groups had increased by4.13%,10.59%,22.22%, but there was no statistically significant difference. The liver CAT levels were significantly higher in the low, middle and high dose garlic oil groups than in the model group6. Serum and liver tissue T-AOC levelsOnly in the model group and the low dose garlic oil group the serum T-AOC levels were significantly lower when compared to the control group (P<0.05). When compared with the model group, the serum T-AOC levels were lower in the low, middle and high dose garlic oil groups. The serum T-AOC levels were increased by6.20%,18.25%,25.00%, but there was no statistically significant difference. The liver tissue T-AOC levels were higher in the low, middle and high dose garlic oil groups than in the model group, and the liver tissue T-AOC levels were increased by1.52%(P>0.05),15.15%(P<0.05),22.22%(P<0.05).7. The histological changes of liverThe results of HE staining showed that the model group showed mild liver damage when compared with the control group. The cell swelling and ballooningdegenerationaround the central vein were found in the model group. The situations in there garlic oil groups were much better than in the model group. There garlic oil groups showed no significant histological changes when compared with the control group. CONCLUSIONS1. Garlic oil can prevent the hepatotoxicity induced by rifampicin and isoniazid.2. The mechanism of garlic oil against rifampicin and isoniazid hepatotoxicity may be related to its antioxidant capacity. |
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