Vol. 10, No 3, 2003 pp. 111 - 115
UC 616 .61:577.15
ANALYSIS FOR DNA ADDUCTS, OCHRATOXIN A
CONTENT
AND ENZYME EXPRESSION IN KIDNEYS OF PIGS
EXPOSED TO MILD EXPERIMENTAL CHRONIC OCHRATOXICOSIS
T. Petkova-Bocharova1, C. El Adlouni1,
V. Faucet1, A. Pfohl-Leszkowicz1,
P.G. Mantle2
1 Ecole Nationale Supérieure Agronomique
de Toulouse, Lab. Toxicology & Food Safety, Avenue Agrobiopole,
31326 Auzeville-Tolosane, France
2 Imperial College London, Department
of Environmental Science & Technology, SW7 2AZ, UK
E-mail: p.mantle@imperial.ac.uk
Summary. Further study of pig renal tissue obtained by unilateral
nephrectomy after six months on feed artificially contaminated with ochratoxin
A (OTA) has revealed significant new information. Whereas there was no
evidence of DNA adducts in either control animal, as tested by 32P
post-labelling, there was a differential pattern of occurrence in male
and female treated pigs. DNA adducts occurred across cortex and medulla
in the male, but most clearly in the cortico-medullary region. Adducts
were only detected in the female in the cortex. Microsomal preparation
from these kidneys consistently catalysed the formation of DNA adducts
in vitro in the presence of OTA; none was formed without OTA. The ochratoxin
A content of a kidney of a treated pig (about 15 micrograms) contrasted
with the 1 micrograms found in that of control pigs, the latter reflecting
significant though slight contamination of some commercial feed with ochratoxin
A in Bulgaria but which did not appear to have any adverse effects in this
pig experiment. Small amounts of fluorescent compounds more polar than
OTA were detected in kidney extracts. Activities of the enzymes ECOD, PROD
and EROD in microsome preparations from renal cortex and medulla were variously
different in male and female animals, reflecting different expressions
of cytochromes P450. Western blot analysis
also indicated that OTA modulated cyclooxygenase (COX) pathways differently
in males and females in ways that might theoretically be disadvantageous
for the male.
Key words: Ochratoxin A, DNA adducts, 32P
post-labelling, protein synthesis, renal enzyme activity, pig, nephrotoxicity
ANALIZA DNA ADUKTA SADRŽAJA OCHRATOXIN-A
I EKSPRESIJE ENZIMA
U BUBREZIMA PRASADI IZLOŽENIH BLAGOJ EKSPERIMENTALNOJ
HRONIČNOJ OCHRATOXICOSI
Kratak sadržaj: Dalja studija tkiva bubrega dobivenih unilateralnom
nefrektomijom prasadi koji su hranjeni hranom veštački kontaminiranom ochratoxin-om
A (OTA), dala je značajne nove informacije. Nije bilo dokaza DNA adukta
kod kontrolnih životinja testiranih obeležavanjem pomoću 32P,
već je zabeleženo različito ponašanje muških i ženskih tretiranih životinja.
DNA adukti su se javljali u korteksu i meduli mužjaka, ali najjasnije u
kortiko-medularnoj regiji. Kod ženki su uglavnom nalaženi u korteksu. Mikrozomalna
preparacija ovih bubrega, permanentno je katalizovala stvaranje DNA adukta
in vitro u prisustvu OTA, dok se isti nije formirao u odsustvu OTA. Sadržaj
ochratoxin-a A u bubregu tretiranih prasadi (oko 15 mikrograma) značajno
se razlikovao od 1 mikrograma nadjenog u kontroli, što je bila posledica
kontaminacije neke komercijalne hrane ochratoxin-om A u Bugarskoj, što
nije dovelo do neželjenih efekata u ovim eksperimentima. Male količine
fluorescentnih sastojaka polarnijih od OTA su otkrivene u ekstraktima bubrega.
Aktivnosti enzima ECOD, PROD i EROD u preparacijama mikrozoma iz korteksa
i medule bubrega u različitom stepenu su se razlikovale kod ženki i mužjaka,
što je odražavalo različitu ekspresiju cytochrom-a P450.
Western blot analiza je takodje pokazala da OTA različito moduliše cyclooxigenase-ni
put (COX) u mužjaka i ženke na način koji bi možda teorijski bio nepovoljniji
za mužjake.
Ključne reči: Ochratoxin A, DNA adukti, obeležavanje 32P,
sinteza proteina, aktivnost renalnih enzima, prase, nefrotoksičnost
