Ultrastructural Studies on the Oviduct in emu (Dromaius novaehollandiae).
Raghu Naik1, Santhi lakshmi2, Pramod kumar3, and K.B.P.Raghavender4.
Department Of Veterinary Anatomy
College of Veterinary Science,Rajendranagar,Hyderabad-500030.(Telangana)
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ABSTRACT
The mucosal surface contained spirally oriented unbranched longitudinal ridges in the funnel part of infundibulum. The magnal mucosa contained different folds, of which the primary folds were more prominent and showed deep clefts in between. The surface epithelium of the magnum contained ciliated and non ciliated columnar cells, goblet cells. The mucosa of isthmus contained large mucosal folds in longitudinally orientation with deep crypts in between opening to the surface. These large folds were branched and carried secondary and tertiary ones. The mucosa of uterus contained leaf like longitudinal folds, which were compact and tortuous and separated by deep narrow clefts. The mucosa was lined by ciliated cells with several openings of the tubular glands opening on to the surface in between and some of these openings contained secretary substances. The mucosa of vagina contained thin longitudinal mucosal folds, the surfaces of which were lined with both ciliated and non ciliated columnar epithelial cells.
Key words: Emu, Oviduct, Ultrastructure.
The emu is the second largest bird and belonged to order Ratite. These birds are reared commercially in many parts of the world for their meat, oil, skin and feathers, which are of high economic value (Sibley and Ahlquist, 1990; Patodkar et al., 2009; Sreedevi et al, 2012; Supriya Shukla et al, 2013). The ultrastructural studies on the Oviduct have been carried out in Ostrich (Sharaf et al. 2012). So the present study was initiated to examine the ultrastructure of the Oviduct in emu ( Dromaius novaehollandiae).
MATERIALS AND METHODS
For SEM, fixed samples collected from different regions of oviduct were dehydrated in series of graded alcohol and were dried with CPD unit.The dried samples were mounted over the stubs with double-sided conductivity tape and were coated by a thin layer of gold metal over the samples using an automated sputter coater for about 3min (Bozzola et al., 1999).The samples were scanned under Scanning Electron Microscope (model: JOEL-JSM 5600, JAPAN).
For TEM, the tissues from different regions of the oviduct were dehydrated in series of graded alcohol from 50% to 100% for 40 minutes each, infiltrated in 1:1 alcohol and resin, pure resin and later embedded in pure Spurr resin. Both semi thin and ultra thin sections were cut with a glass knife on a Leica Ultra cut UCT-GA-D/E-1/00 ultramicrotome. Semi thin sections of 200-300 nm were stained with Toludine blue whereas, ultra thin sections (50-70 nm) were mounted on copper grids. Then the sections were stained with saturated aqueous Uranyl acetate for 30 minutes and counter stained with 4% Lead citrate for 20minutes (Bozzola et al.,1999) and were later observed under Transmission Electron Microscope (Model:Hitachi,H-7500,JAPAN).
RESULTS AND DISCUSSION
1.Infundibulum:- The mucosal surface contained spirally oriented unbranched longitudinal ridges in the funnel part of infundibulum. The tubal part of infundibulum contained small secondary folds on the larger primary ridges. Parto et al. (2011) also reported that the infundibulum of the turkey showed spirally oriented longitudinal ridges and contained small secondary folds on them.
The surface of infundibulum was lined by ciliated columnar epithelium with deep furrows in between. Similar finding was reported in ostrich by Saber et al. (2009). In the present study, the epithelial cells contained cylindrical cilia of uniform length and microvilli.
In the present study, the tubular glands were opened onto the surface epithelium between the mucosal folds. However Wyburn et al. (1970) reported that the tubular glands in sub-epithelial layer were lined with cells containing large granular endoplasmic reticular (GER) space filled with homogeneous material of low electron density. Similar observations were reported in fowl.
In the present study, four types of cells were observed in the lining epithelium of the infundibulum, Viz., ciliated, non ciliated, basal and mucous secretary cells (Goblet cells). However, Wyburn et al. (1970) reported that the surface ridges of infundibulum in fowl was lined with columnar epithelium and contained only ciliated cells, with little secretary activity and granular cells with electron dense granules.
2.Magnum:– The magnal mucosa contained different folds, of which the primary folds were more prominent and showed deep clefts in between. Deep furrows or clefts between the ridges were reported to be observed in adult chicken (Jung et al., 2011) and turkey (Parto et al., 2011). Secondary folds were noticed on the primary folds of magnum. However, the primary folds accompanied by secondary and tertiary folds were reported to be noticed in the proximal part of the magnum, while in the distal part the folds were reported simple without secondary ones in turkey (Parto et al., 2011). The openings of the proprial glands appeared on the surface epithelium and at the bases of the deep clefts, which agreed with the observations in ostrich by Saber et al. (2009). The surface epithelium of magnum was pseudostratified ciliated columnar epithelium. Similar finding was reported in fowl by Hodges (1974).
The surface epithelium of the magnum contained ciliated and non ciliated columnar cells, goblet cells. Similar observations were reported in the magnum of adult chicken by Jung et al. (2011). However, the epithelium was reported to contain ciliated and non ciliated cells predominated with ciliated cells by Saber et al. (2009) in ostrich. In contrary to this, in the present study, the lining epithelium of magnum contained more number of non ciliated columnar cells and goblet cells. However, the similar epithelium with more number of goblet cells was also reported in the mucosa of magnum in hen by Mehta and Guha (2012) and Sharaf et al., (2012) in ostrich.
The columnar epithelial cells contained granules of low electron density, which agreed with the reports of Wyburn et al. (1970) in fowl. Three basic cells were observed in the basal part of tubular glands viz., type A cells packed with strongly electron dense granules, type B cells filled with amorphous material of low electron density and numerous RER profiles and type C cells with few strongly electron dense granules and prominent organelles, RER Spaces and golgi complex. The above features correlated with the reports of Wyburn et al. (1970) in the magnum of fowl.
3.Isthmus:- In present study, the mucosa of isthmus contained large mucosal folds in longitudinally orientation with deep crypts in between opening to the surface. These large folds were branched and carried secondary and tertiary ones. Similar findings were reported by Parto et al. (2011) in turkey. *The openings of the tubular glands on the surface epithelium covering the mucosal folds and covered by secretary substances in present study, which agreed with the observations reported by Balash et al. (2013) in turkey. In present study, the surface epithelium was pseudostratified ciliated columnar and contained three types of cells viz., ciliated and non ciliated columnar cells and goblet cells. However the surface epithelium was reported to comprise two cell types, ciliated columnar cells and non ciliated secretary cell in turkey by Balash et al. (2013).
In present study, the ciliated epithelial cells were less columnar containing microvilli and cilia on their apical surfaces and presented clusters of mitochondria around the roots of the cilia, which agreed nearly the observations of Draper et al. (1972) in fowl. However, the microvilli were reported to be presented amongst the cilia as elsewhere in the oviduct epithelium in fowl (Aitken and Johnston, 1963 and Aitken and Wyburn, 1963). In present study, the lining cells were reported to contain nuclei and numerous scattered electron dense granules in their apical expanded parts more towards the apex. Similar observations reported by Draper et al. (1972) in fowl. The non ciliated cells associated with GER profiles and cisternae filled with a homogeneous material of medium electron density, which was found to be similar to the observations reported in fowl by Draper et al. (1972).
4.Uterus:- In present study, the mucosa of uterus contained leaf like longitudinal folds, which were compact and tortuous and separated by deep narrow clefts. The mucosa was lined by ciliated cells with several openings of the tubular glands opening on to the surface in between and some of these openings contained secretary substances. Similar findings observed by Saber et al. (2009) in ostrich. Our findings also agreed the observations of Parto et al. (2011), who revealed that uterine mucosal folds in turkey were longer and more complex, compressed and longitudinally oriented with voluminous interfold spaces between folds.
The surface epithelium was pseudo stratified columnar ciliated epithelium with ciliated, non-ciliated, basal and goblet cells, of which the non ciliated columnar cells were predominant. While, Johnston et al. (1963), reported that the lining epithelium of uterus in fowl contained ciliated cells, non ciliated cells and electron lucent cells.
According to Jhonson et al. (1963), the ciliated cells exhibit well developed regularly arranged cilia intermingled with microvilli. The ciliated cells contained elongated or irregular shaped nuclei of euchromatic type. In the present study also the ciliated cells exhibit well developed regularly arranged cilia intermingled with microvilli, but the nuclei of ciliated cells positioned apically and that of non ciliated cells lay basally.
The cytoplasm of the ciliated cells contained several mitochondria, rough endoplasmic reticulum, free ribosomes, electron dense granules and bundles of fibrils in the supra nuclear region. Similar observations were reported in fowl by Jhonson et al. (1963) and ostrich by Saber et al. (2009)
5.Vagina:- In the present study, the mucosa of vagina contained thin longitudinal mucosal folds, the surfaces of which were lined with both ciliated and non ciliated columnar epithelial cells. These observations are in total agreement with description in vagina by Parto et al. (2011) in turkey. However, the primary and secondary mucosal folds of the vagina were reported to be flattened during the fixation process with numerous parallel surface grooves in turkey (Bakst et al., 2007).
In present study, the surface epithelium showed four types of cells, ciliated, non ciliated granular cells, goblet and basal cells. Similar observations were reported in quail by Bansal et al. (2010) in quail.
In present study, the ciliated cells were narrow with an expanded apex carrying the cilia. Ciliated cells typically contain oval or round shaped nucleus. The apical plasma membrane exhibits cilia and microvilli. In present study, the apical cytoplasm contained secretary granules and both electron dense and ectronlucent membrane bounded granules in addition to rough endoplasmic reticulum, mitochondria, free ribosomes and golgi apparatus. The nuclei were euchromatic with prominent nucleoli. The above features were similar to the findings recorded by Muwazi et al. (1982) in ostrich, Wyburn et al. (1970) in hen and Fertuck and Newstead (1970) in quail
The non-ciliated cells contained secretory granules and vacuoles either in the middle or apical regions of cells. These observations are in total agreement with reported in vagina by Saber et al. (2009) in ostrich.
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