Curcumin Ameliorates Benzo[a]pyrene-Induced DNA Damages in Stomach Tissues of Sprague-Dawley Rats.

Benzo[a]pyrene (BaP) is a well-known carcinogen formed during the cooking process. Although BaP exposure has been implicated as one of the risk factors for lung cancer in animals and humans, there are only limited data on BaP-induced gastrointestinal cancer. Therefore, this study investigated the protective effects of curcumin on BaP-induced DNA damage in rat stomach tissues. BaP (20 mg/kg/day) and curcumin (50, 100, or 200 mg/kg) were administered daily to Sprague-Dawley rats by oral gavage over 30 days. Curcumin was pre-administered before BaP exposure. All rats were euthanized, and liver, kidney, and stomach tissues were removed at 24 h after the last treatment. We observed that aspartate aminotransferase (AST), alanine aminotransferase (ALT), and glucose levels were significantly reduced in rats treated with high dose co-administration of curcumin (200 mg/kg) compared to BaP alone. The expression levels of cytochrome P450 (CYP) 1A1 and CYP1B1 were significantly increased in the liver of rats treated with BaP. However, co-administration of curcumin (200 mg/kg) with BaP markedly reduced CYP1A1 expression in a dose-dependent manner. Furthermore, plasma levels of BaP-diolepoxide (BPDE) and BaP metabolites were significantly reduced by co-administration of curcumin (200 mg/kg). Additionally, co-administration of curcumin (200 mg/kg) with BaP significantly reduced the formation of BPDE-I-DNA and 8-hydroxydeoxy guanosine (8-OHdG) adducts in the liver, kidney, and stomach tissues. The inhibition of these adduct formations were more prominent in the stomach tissues than in the liver. Overall, our observations suggest that curcumin might inhibit BaP-induced gastrointestinal tumorigenesis and shows promise as a chemopreventive agent.

Comparative study of serum 8-hydroxydeoxy-guanosine levels among healthy offspring of diabetic and non-diabetic parents.

OBJECTIVE: Parental diabetic status might inherit the likelihood of disease susceptibility. The risk of Type 2 diabetes mellitus is increased among individuals with diabetic parents. Moreover, oxidative stress is thought to be a risk factor in the onset and progression of diabetes. 8-hydroxydeoxy-guanosine (8-OHdG) is widely analyzed biomarker to assess the oxidative DNA damage. We aimed to investigate that serum 8-OHdG level among offspring of diabetic and non-diabetic parents. MATERIALS AND METHODS: A total of 84 volunteers participated in the study. Questionnaires were applied to record information including demographics, physical activity, smoking, and family history. Blood samples were collected, and laboratory investigations 8-OHdG levels, lipid, and glucose were analyzed using the standard technique. Finally, 24 samples were considered for further analysis. Student's t-test was applied for statistical analysis. RESULTS: Serum 8-OHdG levels were significantly (P < 0.05) high among healthy offspring of diabetic in comparison of healthy offspring of non-diabetic parents. While nonsignificant differences were found in their body mass index, glucose, and lipid level between the groups. CONCLUSION: There is possibility of a mild degree of oxidative DNA damage among offspring of diabetic due to family history. Such understanding is essential to avoid other modifiable risk factors related to lifestyle and dietary habit which could possibly control further oxidative stress, to delay the onset of diabetic especially among offspring of diabetic parents.

Effects of Ginkgo biloba extract on biomarker expressions during aflatoxin B_1-induced hepatocarcinogenesis in Wistar rats / 肿瘤

Objective:To study the effect of Ginkgo biloba extract (EGb761) on metabolism of aflatoxin B_1(AFB_1) in Wistar rats. Methods:Seventy one Wistar rats were divided into three groups at random: group A (AFB_1 group), group B (AFB_1+EGb761 group), and group C (control group). The rats in groups A and B were given AFB_1(intraperitoneal injection, 100-200 μg/ kg body weight, 1-3 times/week). The rats in group B were fed the food containing EGb761 while the rats in groups A and C were given normal food. Blood samples were collected and liver biopsy was performed on the 14th, 28th and 42nd week. All the rats were sacrificed at the 64th week. The incidence of hepatoma was observed. The hepatic phase Ⅰ drug-metabolizing enzyme CYP450 and phase Ⅱ enzyme GST were detected by spectrometry. The serum AFB_1-lysine adduct was determined by high performance liquid chromatography (HPLC). The expression of 8-hydroxydeoxyguanosine(8-OHdG) was measured by immunohistochemistry. Results:The incidence of hepatocellular carcinoma (HCC) in group B was significantly lower than that in group A (26.92% vs 76.00%,P<0.001). No hepatocellular carcinoma developed in group C. EGb761 had no effects on the activities of CYP450 and GST in rat liver tissues. The level of AFB_1-lysine adduct reached the peak (4 356.01 pg/mg albumin) at the 14th week in group A. EGb761 significantly inhibited the formation of AFB_1-lysine adducts in serum by 13.07% at the 14th week (P＝0.033), and 73.63% at the 42nd week (P＝0.002). The expression of 8-OHdG protein in rat liver tissues in group B was significantly lower than that in group A at the 28th, 42nd, and 64th week (P<0.05). Conclusion:The main mechanism underlying the effect of EGb761 in blocking hepatogenesis induced by AFB_1 may not be fully related with its influence on the activity of liver phase Ⅰ and phase Ⅱ metabolizing enzymes. EGb761 inhibites the production of AFB_1-lysine addcuts, decreases the expression of 8-OHdG protein, and finally alleviates the DNA oxidative injury, which may be one of the mechanisms for the effects of EGb761 in inhibiting or delaying hepatogenesis induced by AFB_1.