Transcript Slide 1

Importance of phenol-rich virgin olive oil in the host modified
polar fatty acids against L.monocytogenes infection in mice
Jasminka Giacomettia, Maja Abramb, Ivana Bogeticd, Hrvoje Krizana and Damir Muhvicc
University of Rijeka, School of Medicine, aDept. of Chemistry and Biochemistry, bDept. Microbiology and Parasitology, cDept. of
Physiology and Pathophysilogy; dStudent of the School of Medicine, Brace Branchetta 20, HR-51000 Rijeka, Croatia
E-mail: [email protected]
INTRODUCTION
Animal studies generally support the idea that olive oil is capable of modulating functions of cells of the immune system. The major components of olive oil that
influence some biological activities are high oleic acid and polyphenols. The Gram-positive facultative intracellular bacterium Listeria monocytogenes is a model pathogen
for elucidating important mechanisms of the immune response.
Olive oil diet produces an immunosuppressive state responsible for the impairment of host immune resistance against L.monocytogenes that hinders the efficient
elimination of microorganisms.
Here, we examine the influence of olive oil diet and isolated olive oil polyphenols on liver host polar fatty acids modification against L.monocytogenes infection in mice,
helps in the current state of knowledge concerning the effects and interactions of olive oil on immune system functions, as well as the their action in the preservation of
host immune defense.
EXPERIMENTAL
Female Balb/c mice, 8–10 weeks old were divided into 3 groups as follows: Group 1 – fed standard diet; Group 2 – fed olive oil (5%,w/w); Group 3 - fed standard diet
and then i.p. simultaneously injected saline phenolics extract (10 mg/kg) and subletal dose L. monocytogenes suspension (200 l, 2 x 107 CFU/ml). Each group had
custom control (uninfected) animals. The evaluation of L.monocytogenes infection was carried out at the days 1, 3 and 6 after induced infection by the collection and
processing of the serum, liver, brain and spleen.
A third of the liver was used for histological analyses (H&E strain), and the second third was used for the bacterial growth determination by the colony forming unit (CFU
per g of tissue). The last third was used for the determination of the polar fatty acid composition (PL FAs).
Liver PL FAs were isolated and purified by solid-phase-extraction (SPE) method using an aminopropylsilica column and subsequently determined by gas chromatography
(GC).
Calculations and Statistical Analysis
DYNAMICS OF EXPERIMENTS
SFAs=% (14:0+16:0+18:0+20:0+22:0+24:0); MUFAs=% (14:1+16:1+18:1+20:1); PUFAs=% (PUFAn-3 + PUFAn-6);
PUFAs n–3 =% (20:5n-3+22:5n-3+22:6n-3);
PUFAs n–6 =% (18:2n-6+18:3n-6+20:2n-6+20:3n-6+20:4n-6+22:4n-6); D9 C18 index =18:1n-9/18:03; D6D
index=[(18:3n-6+20:3n-6)/18:2n-6]1; D5D index=[(20:4n-6/(20:3n-6)]1.
Data are reported as mean ±S.D. Statistical significance was assumed with p<0.05. All statistical analyses were conducted
using the Statistica software package for Windows, StatSoft, Inc. (2005), Version 7.1. The significance of the differences was
analyzed by the Descriptive Statistics by Groups (Breakdown) - analysis of variance and Post-hoc Comparisons of Means
using Scheffe test.
a.
Group 1
Group 2
Group 3
Group 2
Ex
Ex
Ex
3
6
3 wks fed olive oil
1
Time post-infection (days)
START of
experiments
b.
Serum, liver, spleen and brain collection
Group 1 – fed standard diet and then 2x107 CFU/ml L. monocytogenes suspension i.p. injected
into each mouse;
Group 2 – fed 3-wks before olive oil diet and then 2x107 CFU/ml L. monocytogenes suspension
i.p. injected into each mouse;
Group 1
Group 3 – fed standard diet and then phenolics extract and 2x107 CFU/ml L. monocytogenes
suspension i.p. simultaneously injected into each mouse
OOP=10 mg/kg olive oil phenolics extracts (saline solution, i.p.)
b.
a.
Spleen
8
Group 3
Group 2
Group 1
log10 CFU/g
6
4
2
0
0
1
2
3
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5
6
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Time post-infection (days)
Liver
8
Group 3
Group 2
Group 1
log10 CFU/g
6
4
2
Group 2
0
0
1
2
3
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5
6
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Time post-infection (days)
Brain
8
Group 3
Group 2
Group 1
log10 CFU/g
6
4
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0
0
1
2
3
4
5
6
7
Time post-infection (days)
Figure 2. a. Bacterial growth by the determination of colony forming unit (CFU per g of tissue) in the
liver, brain and spleen;
b. Histological analysis of the liver from female Balb/c mice: H & E-stained liver sections at the 1st, 3th
and 6th days after infection treated mice in the group 1, 2 and 3; magnification = 100X.
Group 3
CONCLUSIONS
L.monocytogenes significantly altered the fatty acid composition of the host liver
membrane phospholipids during 6-day infection monitoring.
The n-3/n-6 ratio was significantly increased in the group fed olive oil and olive oil
polyphenols compared to the control.
MUFA was higher in the group fed olive oil and olive oil polyphenols compared to the
control.
Bacterial growth depended on the examined organs; major bacteria were found in the
spleen, and minor in the brain.
The protective role of olive oil diet reflected on found minor bacterium number and the
absence on pathohistological and metabolic liver damage.
References
Figure 1. a. Differences in the liver PL FAs profile.* significantly differences among
groups were found by the Descriptive Statistics by Groups (Breakdown) - analysis of
variance (p<0.05);
b. Differences in the liver n-6, n-3, SFA, MUFA i PUFA FAs profile.* significantly
different from the control were determined by the Descriptive Statistics by Groups
(Breakdown) - Post-hoc Comparisons of Means using Scheffe test (p<0.05).
Acknowledgements
This work was supported by the Croatian Ministry of Science, Project No. 0620000000-0221 and 062-0621273-1235, DIOKI,d.d. Zagreb and The university of
Rijeka foundation.
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