الفهرس 
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Abstract
Cardiovascular diseases are huge problem on human health and one of the leading causes of mortality around the world. One of these diseases is cardiac hypertrophy, which is a thickening of the cardiac muscles as a common complication of hypertension.
Calanus oil is a natural product extracted from the marine zooplankton Calanus finmarchicus. It is being the major zooplankton biomass and a novel source of omega-3 fatty acids. There is no side effects for calanus oil is seen. It has many medical uses such as anti-hypertensive, anti-inflammatory, anti-fibrotic and anti-obesity effects.
Thus, the present work was designed to investigate the potential role of calanus oil to ameliorate cardiac hypertrophy and to assess the mechanism of its action in adult male albino mice.
In the current work, a total of forty healthy adult male mice were used. One week after the acclimatization period, the animals were randomly assigned into five groups as follows:
group I (negative control group, n= 7): normal mice, neither treated with calanus oil nor injected with isoproterenol.
group II (CO group, n= 7): mice orally-treated with calanus oil at a daily dose of 400 mg/kg b.wt for 4 weeks.
group III (ISO group, n= 12): Isoproterenol-injected mice. Cardiac hypertrophy was induced by subcutaneous injections with isoproterenol (5 mg/kg in 0.9% saline), once daily for 14 consecutive days.
group IV (ISO+ CO200 group, n= 7): ISO-injected mice, then orally-treated with calanus oil (200 mg/kg b.wt) daily for 4 weeks.
group V (ISO+ CO400 group, n= 7): ISO-injected mice, then orally-treated with calanus oil (400 mg/kg b.wt) daily for 4 weeks.
At the end of the experiment, blood and heart samples was collected and subjected to different analyses according to the following protocol:
ــEchocardiography was performed to assess alternations in cardiac structure and function.
ــ Biochemical analyses to study the effect of calanus oil on LDH, CK-MB, in addition to heart MDA and TAC.
ــ Histopathological studies to study the effect of calanus oil on the pathological characteristics of heart tissue of cardiac hypertrophy mice.
ــ Ultrastructural studies to study the effect of calanus oil on the ultrastructure of heart tissue of cardiac hypertrophy mice.
Quantitative data were analyzed statistically using One-way ANOVA followed by post hoc multiple comparisons (Tukey’s test) for comparative analyses between the groups.
Cardiac hypertrophied mice showed significant increase in heart gross morphology, cardiomyocytes diameter, serum LDH CK-MB, and tissue MDA concentrations, as well as significant decrease in TAC concentrations compared with those of the negative control group.
Histological results showed that cardiac hypertrophied mice exhibited disorganization in their cardiac architecture, increase in the thickness of left ventricle, inflammatory cells, edema and severe interstitial fibrosis that was confirmed by echocardiography, which showed significant increase in left ventricular mass and interventricular septal thickness, and significant thickening of left ventricular posterior walls. Such thickening was accompanied by a significant decrease in the left ventricular cavity size, which affected the cardiac function as manifested by significant decreases in the measurements of the ejection fraction and fractional shortening.
Ultrastructural results showed that the heart of the cardiac myofibrils hypertrophy group exhibited mitochondria ruptured and dissolved; swollen with fragmented cristae and presence of vacuolations.
However, treating cardiac hypertrophic mice with calanus oil significantly reduced the relative heart weight, cardiomyocytes diameter, LDH, CK-MB and MDA, and significantly increased TAC.
However, treating cardiac hypertrophy with calanus oil showed significant decrease in the thickness of left ventricle, organization in their cardiac architecture with no inflammation, edema and very few fibrosis. This result was confirmed by echocardiography results such as significant decrease in LVPW, IVS, and LVM, and significant decrease in LVID, as well as increase in cardiac function (FS, EF).
However, treating cardiac hypertrophic mice with calanus oil showed nearly normal appearance of myofibrils, sarcomere structure, mitochondria and presence of very few vacuolations. The low and high dose of calanus oil nearly gave the same results, but the high dose ameliorated better cardiac hypertrophy.
In conclusion, the current study provided morphometric, biochemical, histological and ultrastructural evidences supporting the promising anti-hypertrophic effect of calanus oil against isoproterenol induced cardiac hypertrophy and fibrosis. Therefore, it could be used as a potential pharmacological intervention in the management of cardiac hypertrophy.