Schisandra chinensis Oil Attenuates Aristolochic Acid I-Induced Nephrotoxicity in vivo and in vitro / 中国结合医学杂志

OBJECTIVE@#To investigate the protective effects of Schisandra chinensis oil (SCEO) against aristolochic acid I (AA I)-induced nephrotoxicity in vivo and in vitro and elucidate the underlying mechanism.@*METHODS@#C57BL/6 mice were randomly divided into 5 groups according to a random number table, including control group, AA I group, and AA I +SCEO (0.25, 0.5 and 1 g/kg) groups (n=5 per group). Pretreatment with SCEO was done for 2 days by oral administration, while the control and AA I groups were treated with sodium carboxymethyl cellulose. Mice of all groups except for the control group were injected intraperitoneally with AA I (5 mg/kg) from day 3 until day 7. Histopathological examination and apoptosis of kidney tissue were observed by hematoxylin and eosin and TdT-mediated dUTP nick-end labeling (TUNEL) staining, respectively. The levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and serum creatinine (SCr), as well as renal malondialdehyde (MDA), glutathione, r-glutamyl cysteingl+glycine (GSH), and superoxide dismutase (SOD) were analyzed using enzyme-linked immunosorbent assay (ELISA). Expressions of hepatic cytochrome P450 1A1 (CYP1A1), CYP1A2, and nad(p)hquinonedehydrogenase1 (NQO1) were analyzed using ELISA, quantitative real-time polymerase chain reaction (qPCR) and Western blot, respectively. In vitro, SCEO (40 µ g/mL) was added 12 h before treatment with AA I (40 µ mol/mL for 48 h) in human renal proximal tubule cell line (HK-2), then apoptosis and reactive oxygen species (ROS) were analyzed by flow cytometry.@*RESULTS@#SCEO 0.5 and 1 g/kg ameliorated histopathological changes and TUNEL+ staining in the kidney tissues of mice with AA I-induced nephrotoxicity, and reduced serum levels of ALT, AST, BUN and SCr (P<0.01 or P<0.05). SCEO 0.5 and 1 g/kg alleviated the ROS generation in kidney, containing MDA, GSH and SOD (P<0.01 or P<0.05). SCEO 1 g/kg increased the expressions of CYP1A1 and CYP1A2 and decreased NQO1 level in the liver tissues (P<0.01 or P<0.05). Besides, in vitro studies also demonstrated that SCEO 40 µ g/mL inhibited apoptosis and ROS generation (P<0.05 or P<0.01).@*CONCLUSIONS@#SCEO can alleviate AA I-induced kidney damage both in vivo and in vitro. The protective mechanism may be closely related to the regulation of metabolic enzymes, thereby inhibiting apoptosis and ROS production.

Maternal protein restriction during lactation modulated the expression and activity of rat offspring hepatic CYP1A1, CYP1A2, CYP2B1, CYP2B2, and CYP2E1 during development

Early nutrition plays a long-term role in the predisposition to chronic diseases and influences the metabolism of several drugs. This may happen through cytochromes P450 (CYPs) regulation, which are the main enzymes responsible for the metabolism of xenobiotics. Here, we analyzed the effects of maternal protein restriction (MPR) on the expression and activity of hepatic offspring’s CYPs during 90 days after birth, using Wistar rats as a mammal model. Hepatic CYP1A1, CYP1A2, CYP2B1, CYP2B2 and CYP2E1 mRNA and protein expression, and associated catalytic activities (ECOD, EROD, MROD, BROD, PROD and PNPH) were evaluated in 15-, 30-, 60-, and 90-day-old offspring from dams fed with either a 0% protein (MPR groups) or a standard diet (C groups) during the 10 first days of lactation. Results showed that most CYP genes were induced in 60- and 90-day-old MPR offspring. The inductions detected in MPR60 and MPR90 were of 5.0- and 2.0-fold (CYP1A2), 3.7- and 2.0-fold (CYP2B2) and 9.8- and 5.8– fold (CYP2E1), respectively, and a 3.8-fold increase of CYP2B1 in MPR90. No major alterations were detected in CYP protein expression. The most relevant CYP catalytic activities’ alterations were observed in EROD, BROD and PNPH. Nevertheless, they did not follow the same pattern observed for mRNA expression, except for an induction of EROD in MPR90 (3.5-fold) and of PNPH in MPR60 (2.2-fold). Together, these results suggest that MPR during lactation was capable of altering the expression and activity of the hepatic CYP enzymes evaluated in the offspring along development.

Changes in activity of hepatic xenobiotic-metabolizing enzymes of tiger puffer (Takifugu rubripes) exposed to paralytic shellfish poisoning toxins.

Attempts were made to examine the effect of paralytic shellfish poisoning toxins (PSP) on hepatic xenobiotic-metabolizing enzymes (XMEs) of tiger puffer (Takifugu rubripes). Two groups of nontoxic tiger fish were analyzed, and one group was fed with a PSP-containing diet (PSP group), and another with a PSP-free diet (control group). After 60 days of feeding, they were compared to each other mainly in terms of the activity of XMEs. Both groups did not differ from each other significantly in body weight gain, hepatosomatic index, and condition factor Hepatic level of cytochrome P450 was lower in PSP group than control group. NADPH-cytochrome P450 reductase, NADH-cytochrome b5 reductase, and ethoxyresorufin-O-deethylase (EROD) exhibited a reduced activity in PSP group than control group. Statistical analysis found that the activity or concentration of those enzymes correlated with the hepatic level of PSR with r2=0.497-0.611.

Changes of biomarkers with oral exposure to benzo(a)pyrene, phenanthrene and pyrene in rats

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants present in air and food. Among PAHs, benzo(a)pyrene(BaP), phenanthrene (PH) and pyrene (PY) are considered to be important for their toxicity or abundance. To investigate the changes of biomarkers after PAH exposure, rats were treated with BaP (150 microgram/kg) alone or with PH (4,300 microgram/kg) and PY (2,700 microgram/kg) (BPP group) by oral gavage once per day for 30 days. 7-ethoxyresorufin-O-deethylase activity in liver microsomal fraction was increased in only BaP groups. The highest concentration (34.5 ng/g) of BaP, was found in muscle of rats treated with BaP alone at 20 days of treatment; it was 23.6 ng/g in BPP treated rats at 30 days of treatment. The highest PH concentration was 47.1 ng/g in muscle and 118.8 ng/g in fat, and for PY it was 29.7 ng/g in muscle and 219.9 ng/g in fat, in BPP groups. In urine, 114-161 ng/ml 3-OH-PH was found, while PH was 41-69 ng/ml during treatment. 201-263 ng/ml 1-OH-PY was found, while PH was 9-17 ng/ml in urine. The level of PY, PH and their metabolites in urine was rapidly decreased after withdrawal of treatment. This study suggest that 1-OH-PY in urine is a sensitive biomarker for PAHs; it was the most highly detected marker among the three PAHs and their metabolites evaluated during the exposure period and for 14 days after withdrawal.

CYP1A1 inducing potential of airborne particulate extracts collected during a 25-year period (1975-2000).

Samples of airborne particles from Sapporo, the capital of Hokkaido, Japan, were collected between 1975 and 2000. Major polycyclic aromatic hydrocarbons (PAHs) included in the extracts of airborne particles were investigated for their mutagenicity and potential for inducing drug-metabolizing enzyme cytochrome P450 (CYP)1A1, which is considered to be responsible for the activation of PAHs in airborne particle extracts, as well as in cigarette smoke, to carcinogens and is associated with risk of several cancers. There was a dose-related increase in CYP1A1 activity in human lymphoblastoid cells after exposure to airborne particulates containing PAHs. The mutagenicity of the airborne particles collected in summer was lowest and for those collected in spring was lower than in autumn or winter. Likewise, the winter sample had the strongest CYP1A1 inducing potential while the summer sample had the weakest. CYP1A1 inducing potency was strongly related to the amount of benzo(k)fluorathene (Spearman's rank correlation coefficient (gamma) = 0.97), benzo[a]pyrene g = 0.96), benzo[g,h,i]perylene (gamma = 0.94), benz[a]anthracene (g = 0.93), chrysene (gamma = 0.93) in the extracts during the 25-year period, while the enzyme activity was measurably related to the amount of pyrene (gamma = 0.64) and fluorathene (gamma = 0.54). During the 25-year period, CYP1A1 inducing potential decreased every year together with a decrease in PAHs in the airborne particle extracts. CYP1A1 inducing potential may be one of the most convenient biomarkers with which to estimate the overall carcinogenicity/mutagenicity of airborne particle extracts.

Qualitative study of three cell culture methods / 华中科技大学学报（医学）（英德文版）

Primary rat hepatocytes were cultured using different in vitro models and the enzyme leakage, albumin secretion, and cytochrome P450 1A (CYP 1A) activity were observed. The results showed that the level of LDH was decreased over time in culture. However, on day 5, LDH showed a significant increase in monolayer culture (MC) while after day 8 no LDH was detectable in sandwich culture (SC). The levels of AST and ALT did not change significantly over the investigated time. The CYP 1A activity was gradually decreased in a time-dependent manner in MC and SC. The decline of CYP 1A was faster in MC than in SC. This effect was partially reversed by using cytochrome P450 (CYP450) inducer such as Omeprazol and 3-methylcholanthrene (3-MC) and the CYP 1A induction was always higher in MC than in SC. In bioreactor basic CYP 1A activity was preserved over 2 weeks and the highest albumin production was observed in bioreactor followed by SC and MC. Taken together, it was indicated each investigated model had its advantages and disadvantages. It was also underlined that various in vitro models may address different questions.

Effects of pregnancy and protein-energy malnutrition on monooxygenase O-dealkylation activity in rat liver microsomes

Xenobiotic metabolism is influenced by a variety of physiological and environmental factors including pregnancy and nutritional status of the individual. Pregnancy has generally been reported to cause a depression of hepatic monooxygenase activities. Low-protein diets and protein-energy malnutrition have also been associated with a reduced activity of monooxygenases in nonpregnant animals. We investigated the combined effects of pregnancy and protein-energy malnutrition on liver monooxygenase O-dealkylation activity. On pregnancy day 0 rats were assigned at random to a group fed ad libitum (well-nourished, WN) or to a malnourished group (MN) which received half of the WN food intake (12 g/day). WN and MN rats were killed on days 0 (nonpregnant), 11 or 20 of pregnancy and ethoxy- (EROD), methoxy- (MROD) and penthoxy- (PROD) resorufin O-dealkylation activities were measured in liver microsomes. Only minor changes in enzyme activities were observed on pregnancy day 11, but a clear-cut reduction of monooxygenase activities (pmol resorufin min-1 mg protein-1) was noted near term (day 0 vs 20, means + or _ SD, Student t-test, P<0.05) in WN (EROD: 78.9 + or - 15.1 vs 54.6 + or - 10.2; MROD: 67.8 + or - 10.0 vs 40.9 + or - 7.2; PROD: 6.6 + or - 0.9 vs 4.3 + or - 0.8) and in MN (EROD: 89.2 + or - 23.9 vs 46.9 + or - 15.0; MROD: 66.8 + or - 13.8 vs 27.9 + or - 4.4; PROD: 6.3 + or - 1.0 vs 4.1 + or - 0.6) dams. On pregnancy day 20 MROD was lower in MN than in WN dams. Malnutrition did not increase the pregnancy-induced reduction of EROD and PROD activities. Thus, the present results suggest that the activities of liver monooxygenases are reduced in near-term pregnancy and that protein-energy malnutrition does not alter EROD or PROD in pregnant rats