Histological and Stereological Changes in Growing and Regressing Chicken Ovaries During Development

Abstract

The aim of this study was to evaluate the sequence of the histological and stereological changes that occur in diverse components of left growing and right regressing ovaries of Gallus domesticus as well as the variations in the number and size of the different cell subpopulations from 8-day-old chicken embryo to 4-week-old chickens. Results indicate a bilateral asymmetry in favor of the left ovary at all ages studied. The left ovary shows cortex and medulla, but the right ovary has no cortex, only a medulla. Stereological results show in the left ovary an increase in total volume of all components of the ovarian medulla with advancing development. The right ovary follows a similar pattern until the age of 1-day-old chicken, to regress afterward, thereby, reducing the total volume of blood vessels, lacunar channels, and interstitium, but increasing the total volume of interstitial cells as development progresses; consequently, the total volume of interstitial cells is the dominant component in the right ovary of 4-week-old chickens. Results also reveal that the increase in total volume of interstitial cells in the left ovary at all ages and in the right ovary from 8-day-old chicken embryo to 1-day-old chicken is due to hyperplasia and cell hypertrophy of interstitial cells; hence, in the right ovary, cell hypertrophy is the main cause for the increase in the total volume of interstitial cells from 1-week-old to 4-week-old chickens. Anat Rec, 294:893-904, 2011. V V C 2011 Wiley-Liss, Inc.Key words: histology; stereology; left ovary; right ovary; chickenIn vertebrates, the reproductive system arises as bilateral anlagen, and consequently paired genital organs are commonly found in the adult. In birds, the female reproductive system is unique. Although paired anlagen appear, only the left genital primordia develop further to functional organs, except in birds of prey (Jacob and Bakst, 2007).In the chick, formation of the ovary differs between the right and left sides. In the left ovary, whose development proceeds normally, cortical cords (secondary cords) extend inward from the gonadal epithelium. From 7 days of incubation onward, the cords develop to form a cortex, whereas the medulla is composed of epithelium derived from medullary cords (primary cords) and their enlarged inner spaces (medullary lacunae). In contrast, the right ovary stops further development from 7 days onward. This is due to the absence of secondary cord formation; the right ovary has only a medulla composed of the epithelium of the medullary cord and enlarged lacunae. Eventually, the right ovary becomes smaller than the left (Romanoff, 1960;Stahl and Carlon, 1973;Ebensperger et al

Age Related Histomorphochemical Changes in Ovaries of Punjab White Quail

“…With advancing age, these lacunar channels increased and became wider as reported earlier by Gonzalez Moran [19] in chicken. The medullary vasculature supplied necessary supply for follicular development.…”

“…Similarly, Gonzalez-Moran [19] observed in chicken that the cortex was separated from medulla by a thin layer of connective tissue, which formed the primary tunica albuginea at 8 day old chicken. The tunica albuginea was composed of abundance of collagen fibers with few reticular and elastic fibers in all the age groups studied (Figure 14).…”

“…Similarly, Rao & Vijayaragvan [9] in domestic duck reported that distinction between cortex and medulla was not evident. [19] observed that the left ovary showed welldifferentiated regions, cortex and medulla at 1 day-old chicken but no distinction between cortex and medulla at 4 week old chicken. However, Deka [20] in Pati and Chara-Chemballi ducks found that divisions between cortical and medullary layers became obscured.…”

Pre-Hatching Development of the Alexandria Chicken Ovaries

“…[28] The PGCs and somatic cells had tight junction and desmosomes between them, these junctions important for nutrient, gaseous and energy transmission from somatic cells to PGCs. [18] The left and right gonadal asymmetry detected at HH20 (E.3), [17,29] different from Carlon and Stahl mentioned the L: R gonadal asymmetry appeared at HH23-24 (E. 4-4.5). [20] The L: R gonadal asymmetry detected by the number of PGCs migrating toward the left gonadal ridge more than the right where the left gonadal ridge produce a chemotactic for PGCs more than that produced by the right one.…”

“…[18,31] The undifferentiated gonads enter the stage of sexual differentiation at HH29 (E.6), [32] while, Smith and Sinclair revealed the sexual differentiation in chicken embryo occurred at HH23 (E.4), [33] Sekido and LovellBadge at HH31 (E.7), [9] González Morán at HH34 (E.8). [29] While Intarapat and Satayalai noted the sexual differentiation stage in the quail embryo at days 5-7 of the development. [16] The differentiated left ovary composed of an outer cortex and inner medulla separated from each other by a thin layer of connective tissue that form the primary tunica albuginea.…”