Poster presented at British International Congress of Obstetrics and Gynaecology - 2007

1. The Effect of Exogenous Leptin Administration on Folliculogenesis,
Ovarian Weight and Total Body Weight of Immature Albino Rats
Mona Elshafie, Lecturer in Histology,1 Ola Elgaddar, Resident in Chemical Pathology,2 Ghada Fouad, Assistant Professor in Histology,1 Ayman Ewies,
Consultant Gynaecologist3
1 = Faculty of Medicine, University of Alexandria, Egypt 2 = Medical Research Institute, University of Alexandria, Egypt 3 = The Ipswich Hospital NHS Trust, UK
Background
 Leptin may be the permissive factor for puberty by serving as
a signal to the CNS with information on the critical amount of
adipose tissue stores that is necessary for activation of the
hypothalamic-hypophyseal-ovarian axis.1
 It regulates body metabolism leading to ↓ appetite and ↑
energy expenditure with a net result of ↓ total body weight.2
 Exogenous leptin accelerated the onset of puberty in
immature female rats and stimulated all aspects of their
reproductive endocrine system.3
Objectives
To quantify the number of follicles, ovarian weight and body
weight of immature albino rats treated with leptin when
compared with controls.
Sample
50 immature female albino rats aged 22
days (age of weaning), with an average
body weight of 20-25 grams. They were
house kept under the same environmental
conditions and fed a standard rat food.
No males were housed in the same rack.
Setting
The Histology Department, Faculty of Medicine, Alexandria
University, Egypt, which is licensed for animal care and use.
Method
2. The effect of leptin on ovarian weight:
The weight of both ovaries of leptin-treated rats (mean 52.9 mg ±
SD 6.5) was significantly (p<0.001) higher than that of the
controls (mean 35.9 mg ± SD 11.4), irrespective of age.
3. The effect of leptin on total body weight:
The total body weight of leptin-treated rats (27.4 g ± SD 1.8) was
significantly (p<0.001) less than that of controls (34.6 g ± SD
3.9). Pearson's correlation (r), showed a significant negative
correlation between the duration of treatment and body weight (r
= -0.622, p=0.001).
Conclusion
Exogenous leptin enhanced folliculogenesis, increased ovarian
weight, and reduced total body weight of rats. Its potential role, in
obese women with impaired reproductive functions, needs to be
elucidated.
References
1.Baldelli R., Dieguez C., Casanueva F. (2002) The role of leptin in reproduction:
experimental and clinical aspects. Ann Med, 34, 5-18.
2.Considine R., Sinha M., Heiman M. et al. (1996) Serum immunoreactive-leptin
concentrations in normal-weight and obese humans. N Engl J Med, 334, 292-5.
3.Almog B., Gold R., Tajima K., Dantes A. et al. (2001) Leptin attenuates follicular
apoptosis and accelerates the onset of puberty in immature rats. Mol Cell
Endocrinol, 183, 179-91.
Control Group
 26 rats, 2 of them were
sacrificed at the age of 22
days
 The rest (24) received
daily S.C. injection of 5µg
of the solvent
 Rats were weighed and
sacrificed following the
same regimen as in the
experimental group
Experimental Group
 24 rats
 Each rat received daily
S.C. injection of 5µg
leptin
 Each rat was weighed, 3
were sacrificed every 2
days after injection, i.e. at
24, 26, 28, 30, 32, and 34
days of age
 Then, on approaching the
expected age of maturity
(42-44 days), they were
sacrificed every 4 days
i.e. at 38 and 42 days
 The Ovaries were dissected and weighed.
 Ovarian sections were stained with haematoxylin & Eosin,
and the antral follicles were counted using light microscope.
 The given result represents the mean count / measure of 3
animals in each age category.
 Data presented in the form of mean ± SD for normally
distributed data and median for non-parametric data.
Results
1.The effect of leptin on follicular maturation:
The number of antral follicles was significantly (p<0.001) higher
in the leptin-treated rats (median = 4, range = 0-6) when
compared with controls (median = 0, range 0-5), irrespective of
age.
0
10
20
30
40
50
60
70
22 24 26 28 30 32 34 38 42
Age (days)
OvarianWeight(mg)
Leptin-treated Control
0
1
2
3
4
5
6
22 24 26 28 30 32 34 38 42
Age (days)
numberoffollicles
leptin-treated Control
0
5
10
15
20
25
30
35
40
45
22 24 26 28 30 32 34 38 42
Age (days)
Weight(g)
Leptin-treated Control