Journal of Stress Physiology & Biochemistry, Vol. 7, No. 4,
2011, pp. 51- 68. ISSN 1997-0838
Original Text Copyright (cc) 2011 by Bhat Manjula S. and Yajurvedi H.N.
ORIGINAL
ARTICLE
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QueryDate : 2016-12-24
Cites : 1
Stress induced alterations in pre-pubertal ovarian follicular development in rat
Bhat Manjula S. and Yajurvedi H.N.*
Department of Zoology, University of Mysore, Manasagangotri, Mysore-570 006, India Phone: +91-0821-2419778 (O) 09740970928 9(Mob)
*E-mail: hnyajurvedi@rediffmail.com
Received August 13, 2011
The objective of the study
was to find out whether stress experienced during neo-natal period
alters the timing of formation of pre-antral and antral follicles and
if so, whether pre-treatment with CRH receptor antagonist prevents
these effects in rats. New born rat pups (n= 15) were exposed to
maternal separation (6 hours/ day) from post-natal day (PND) 1 to 7 and
were killed on PND 8, 11 and 15. The time of exposure was randomly
changed every day during light phase (7Am to 7Pm) of the day to avoid
habituation. There was a significant increase in serum corticosterone
levels on PND 8 and 11 in stress group rats compared to controls
indicating stress response in these pups. The ovary of both control and
stressed rats contained oocytes and primary follicles on PND 8 and 11
and in showed progress of follicular development upto to pre-antral and
early antral follicle formation on PND 11 and 15. However, mean number
of healthy oocytes and all categories of follicles at all ages studied
were significantly lower in stressed rats compared to controls.
Concomitant with these changes, number of atreatic follicles showed an
increase over control values in stressed rats. The increase in atresia
of follicles was due to apoptosis as shown by increase in the
percentage of granulosa cells showing TUNEL positive staining and
caspase 3 activity. On the other hand, pre-treatment with CRH- receptor
antagonist (CRH 9-41) 2ng/ 0.1 ml/ rat prior to undergoing stress
regime on PND 1 to 7, prevented alterations in pre- pubertal follicular
development thereby indicating that the ovarian changes were due to
effects of stress induced activation of HPA axis. The results indicate
that, stress during neonatal phase, though does not affect timing of
formation of pre-antral and antral follicles, it does enhance atresia
of follicles of all categories, including follicular reserve, which may
affect the reproductive potential of adults. The results, for the first
time reveal that CRF receptor antagonist prevents pre-pubertal ovarian
stress response.
