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Neonatal and Juvenile Ocular Development in Sprague‐Dawley Rats: a Histomorphological Study
Author(s) -
Vrolyk Vanessa,
Apreutese Ancuta,
Gordon Cedric,
Forster Roy,
Graham Andrew,
Palate Bernard,
Haruna Julius,
BenoitBiancamano MarieOdile
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1179.14
Subject(s) - outer nuclear layer , inner nuclear layer , ganglion cell layer , biology , anatomy , juvenile , epithelium , inner plexiform layer , retina , prenatal development , pathology , andrology , ganglion , fetus , medicine , pregnancy , neuroscience , genetics
This study aimed at evaluating the histomorphological developmental features of the eye in Sprague‐Dawley rats, with focus on the postnatal and juvenile periods. Tissues were collected from 51 rats, from both sexes, aged 1 to 30 days old. As in other altricial species, the eyes of newborn rats are underdeveloped and the eyelids remain closed for approximately two weeks after birth. During the postnatal development, dramatic changes occurred within the retina, when programmed cell death and cell differentiation coexisted. A complete separation of the inner nuclear layer from outer nuclear layer was first observed close to the end of the first week of life, while the nerve fiber, ganglion cell and inner plexiform layers almost reached maturity concurrently with the opening of the eyes, around the end of the second week. At birth, apoptotic bodies were frequently seen within the undifferentiated nuclear layer and peaked at post‐natal day (PND) 8 within the inner nuclear layer. In newborn animals, mitoses formed a contiguous band of proliferating cells within the undifferentiated nuclear layer, adjacent to the photoreceptors layer. Perinatally, the corneal stroma and sclera exhibited high cellularity and became thinner and less cellular with maturity. The corneal epithelium consisted of a single layer of non‐stratified columnar cells during the first ten PNDs, and transformed into 4 to 5 cell layers of stratified squamous epithelium at about PND 14. The lens continuously developed by addition of new lens fibers from the lens epithelium. Between PND8 and PND17, a band‐like region of apoptotic bodies was seen centrally within the zone of nucleated lens fibers. We conclude that, during the first month of life, the rat's eyes undergo a rapid phase of growth and almost reach adult maturity at PND30. These observations will serve as an historical database, useful in pediatric ocular drug development. Support or Funding Information Mitacs