Influence of aflatoxin B1 on mRNA levels of acute-phase proteins and oncoproteins in albino rat liver

Abstract

Background: The effect of aflatoxin B1 (AFB1) administration on expression of genes coding for acute-phase proteins, and nuclear protooncogenes c-fos and c-jun, and alpha-fetoprotein gene has been studied in rats. Methods: AFB1 was administered to male Albino Oxford (AO) rats as a single intraperitoneal dose (1 mg/kg body weight). The expression of genes for albumin, cystein protease inhibitor, fibrinogen, haptoglobin, a1-acid glycoprotein and for c-Fos, c-Jun and alpha-fetoprotein in rat liver was measured by Northern hybridization. Results: The mild increase in the levels of mRNA for acute-phase proteins after AFB1 administration was observed during the first 24 hours. The exceptions were the mRNA levels in liver for cystein protease inhibitor, which were 50%, decreased as compared to the control values. In addition, mild increase of the expression of c-fos protooncogene with two peaks were noted at three (1.3 fold) and 72 hours (1.5 fold) after injection AFB1 to rats. The expression of nuclear protooncogene c-jun at 1 hour and 72 hour after acute poisoning was 2.6 fold and 3.7 fold increased as compared to control values, respectively. The mRNA levels in liver for the alpha-fetoprotein reached a maximum at 1 hour after AFB1 injection and it was 1.8 times higher than the levels in the livers of nontreated animals. Conclusion: Single administration of AFB1 induced increased transcription of c-jun and c-fos genes while typical acute-phase response was not found

Acute phase protein mRNA expressions and enhancement of antioxidant defense system in Black-meated Silkie Fowls supplemented with clove (Eugenia caryophyllus) extracts under the influence of chronic heat stress

“…This result was consistent with the APPs mRNA response to ET and the association of these APPs mRNA levels with tissue damage ensued during ET treatment. The present findings are in agreement with the results reported by previous studies [ 18 , 35 , 36 ] in which APR mRNA expression was reduced in the liver tissue. Moreover, the current study revealed that the diet supplemented 400 mg clove maintained OVT, CP, AGP, CRP and SAA mRNA expression levels in all the organs of heat-stressed Silkie fowls to approximately levels of those fowls maintained at TC.…”

“…The expression of mRNA coding for APPs in the liver is commonly controlled at the transcriptional level [ 35 ]. The liver regulates the expression of these genes in response to diverse extracellular stimuli [ 36 ]. We noted in the current finding that changes in the APPs concentrations were due primarily to the changes in their synthesis by hepatocytes.…”

“…Stress increases the synthesis of APPs which are constitutively expressed and play a crucial protective role for DNA against oxidative damage [ 18 , 35 , 36 ] by maintaining the homeostasis and structural integrity of organs over the stress-induced tissue damage [ 21 ]. Both low and chronic concentrations of ROS may generate DNA damages by allowing gene mutations and structural modifications into the DNA.…”

“…Though, clove induced OVT, CP, AGP, CRP and SAA mRNA expression in the fowls supplemented this level through activation and mobilization of the organs antioxidant protective mechanisms. Clove as natural polyphenolic bioactive compound has a characteristics of overlapping properties that triggered self-maintenance and defense mechanisms in rats [ 35 , 36 , 56 ]. We deduce that the nature of this mechanism might be a tissue specific at different levels of clove and the patterns of diverse APPs mRNA expression.…”

“…However, the mechanisms underlying heat stress induced APR mRNA expression in the immune organs of black Silkie fowls is unobtainable. Studies have revealed that APPs protect DNA from oxidative damage [ 18 , 35 , 36 ], where clove may serve as possible DNA protector. The mechanism by which the elevated temperatures suppress immunity is not completely understood.…”