Histological and Ultra Structure Observations of the Adrenal Gland of Fruit Eating Bat (Rousettus Aegyptiacus)

As general in all mammals, adrenal gland is composed of two distinct portions: an outer cortex and an inner medulla [15] paired right and left flat adrenal glands located to the craniomedial of the kidneys were observed in porcupine (Hystrixcristata). In human, the adrenal glands (suprarenal glands) associated with the kidneys. A gland present top on each kidney like a cap and is embedded in the mass of adipose tissue that encloses the kidney. The adrenal glands are shaped like pyramids; each gland is very vascular and consists of two parts. The central portion is the adrenal medulla and the outer part is the adrenal cortex [6]. Adrenal cortex is subdivided into three zones; the outermost zona glomerulosa that contained cells formed cords and contained lipid vacuoles, the middle thickness and palest zona fasciculata formed of large polyhedral spongiocytes which arranged in longitudinal straight cords separated by straight blood capillaries and the last third narrow zona reticularis formed of small polyhedral deeply stained cells arranged in branching anastmosing cords separated by irregular blood capillaries [7]. Adrenal medulla formed of chromaffin cells that are large polygonal and arranged either in groups around blood vessels or in branching cords. These cells secrete catecholamines (adrenaline and nor-adrenaline). One pair of adrenal glands was found in the Emballonurid bat, Taphozous longimanus against the lateral kidney, left one was pyramidal, but the right was oval. The gland has two layers, inner medulla and outer cortex which have zona glomerulosa and zona fasciculata while the third zone zona reticularis is absent [8]. Adrenal gland considered as a key organ in bat because it plays an important role in metabolism and homeostasis of animals, it protects the organism against acute and chronic stress; Catecholamine’s of the medulla mobilize glucose and fatty acids for energy, muscles and lung for action in acute actress. There is a little information available on anatomy of adrenal gland of Egyptian bats. The present report reveals the anatomy of adrenal glands in Rousettus eagyptiacus.


Introduction
As general in all mammals, adrenal gland is composed of two distinct portions: an outer cortex and an inner medulla [1][2][3][4][5] paired right and left flat adrenal glands located to the craniomedial of the kidneys were observed in porcupine (Hystrixcristata).
In human, the adrenal glands (suprarenal glands) associated with the kidneys. A gland present top on each kidney like a cap and is embedded in the mass of adipose tissue that encloses the kidney. The adrenal glands are shaped like pyramids; each gland is very vascular and consists of two parts. The central portion is the adrenal medulla and the outer part is the adrenal cortex [6].
Adrenal cortex is subdivided into three zones; the outermost zona glomerulosa that contained cells formed cords and contained lipid vacuoles, the middle thickness and palest zona fasciculata formed of large polyhedral spongiocytes which arranged in longitudinal straight cords separated by straight blood capillaries and the last third narrow zona reticularis formed of small polyhedral deeply stained cells arranged in branching anastmosing cords separated by irregular blood capillaries [7]. Adrenal medulla formed of chromaffin cells that are large polygonal and arranged either in groups around blood vessels or in branching cords. These cells secrete catecholamines (adrenaline and nor-adrenaline). One pair of adrenal glands was found in the Emballonurid bat, Taphozous longimanus against the lateral kidney, left one was pyramidal, but the right was oval. The gland has two layers, inner medulla and outer cortex which have zona glomerulosa and zona fasciculata while the third zone zona reticularis is absent [8]. Adrenal gland considered as a key organ in bat because it plays an important role in metabolism and homeostasis of animals, it protects the organism against acute and chronic stress; Catecholamine's of the medulla mobilize glucose and fatty acids for energy, muscles and lung for action in acute actress. There is a little information available on anatomy of adrenal gland of Egyptian bats. The present report reveals the anatomy of adrenal glands in Rousettus eagyptiacus.

Material and Methods
The specimen used was females non pregnant adult Frugivorous bat Rousettus eagyptiacus. Each animal was euthanized by chloroform, dissected and the adrenal gland go out, thin fixed with 10% formalin for general histology and stained with Hematoxylin and eosin stain [9].

Transmission Electron Microscopy:
For transmission electron microscope, small pieces of 1 x 1 x 1 mm of pituitary gland of bats were obtained and were rapidly processed as follow: -a. Fixation: Small pieces of fresh specimens were fixed in a mixture of

Infiltration:
Dehydrated tissues were initiated in 1: 1 solution of propylene oxide and epon mixture. Infiltration was continued with 1: 3 (propylene oxide: epon mixture) overnight at room temperature.

e. Embedding:
Embedding was carried out using freshly prepared araldite epon mixture in capsules pre-dried for 1-3 hours.

f. Polymerization:
The capsules were polymerized at 60˚C and then the polymerized capsules were cured at room temperature for at least a day before attempting to section. Grids were washed in three successive glass bottles containing distilled water. After the last bath, grids were dried on a filter paper.
Sections were then stained with freshly prepared lead citrate that centrifuged at 5000 rpm for 10 minutes and used for staining for 10 minutes as in uranyl acetate, then washed with 0.02 N Noah and finally with freshly distilled water. The grids dried on filter paper and examined with electron microscope (TEM Philips 400 T at 80 Kv). Photos were made on Kodak EM sheet films; developed then enlarged and printed and investigated.

Result The Histological Structure
In R. aegyptiacus the pair glands appear embedded at the lateral surface of each kidney covered by thick connective tissue capsule.
It is oval and has two zones an outer cortex and an inner medulla

The Zona Fasciculate
This layer constitutes the major portion of the adrenal cortex.

The Medulla
The, medulla consists of chromaffin cells arranged in small groups or short cords surrounded by blood capillaries and

Discussion
The study aims to describe the histological and the ultrastructure of the adrenal gland of Rousettus aegyptiacus. The result showed that the left and right gland oval different from Emballonurid bat, Taphozous longimanus in which the left adrenal gland is pyramidal, and the right adrenal gland is oval [8]. Adrenal gland divided into cortex and medulla, the cortex surrounding the medulla in different thickness as same to other species of mammals.
According to [10], the duck cortex constitutes 68.2%, the medulla 28.6% and vascular space 3.2% of the total area. The adrenal cortex is divided into three distinct zones, zona glomerulosa, zona fasciculata and zona reticularis. A distinct zone of the cortex is observed in M schereibersii [11], M lyra lyra [12], V pipistrellus [9], P giganteus giganteus and R leschenaultia [13], Cynopterus sphinx, H lankadiva [14] and P giganteus giganteus [15]. In the present species, zona reticulosa is distinct but in some species, it is present in the form of islets of cortical cells in the medullary region in T melanopogon [16]. In the present study, zona glomerulosa consists of polyhedral glomerular cells which appear group of 3-7 acini or cells. Similar structure is also observed in the zona glomerulosa of Taphozous Kachhensis [17] in T longimanus, Hipposideros lankadiva [18]. In Cynopterus sphinx the cells are arranged in groups.