A total of twelve healthy adult Madras Red ewe and Boer local she-goat teats were histologically and immunohistochemically examined. In between the teat canal and teat cistern Furstenberg’s rosette was appeared as modified zone of mucosa thrown into primary and secondary folds. The mucosal folds were lined by a bilayered cuboidal epithelium. Subepithelial area of rosette was composed of numerous lymphocytes, polymorphonuclear leukocytes, macrophages and plasma cells. Mucosa below the Furstenberg’s rosette was lined by stratified squamous keratinized epithelium. Immunohistochemical staining of rosette by CD3 antibody revealed the localization of intraepithelial ‘T’ lymphocytes in the mucosal folds. ‘T’ lymphocytes were also localized in the lamina propria region
Teat is the primary route of entry of ascending infections by microorganisms that causes mastitis in mammary gland of ruminants. Apart from the natural protective barriers in the teat end such as keratin produces by teat canal epithelium and teat skin, there is a rosette like structure that comprises numerous antibody producing cells and phagocytes to fight entering antigens from the external environment.
In cows, at the union of teat cistern and teat canal, the double-layered epithelium of teat cistern, abruptly changed ventrally to stratified squamous epithelium of teat canal. This region is called Furstenberg’s rosette (Nickerson and Akers, 2011). Under low magnification, examination of cross section of the teat sinus in cows reveals the epithelial folds, covering the closed teat canal resembling the petal-like arrangement or rosette of a flower (Smolenski, 2018). There is a Furstenberg’s rosette associated lymphoid tissue (FALT) in mammary gland of cow and antigens are received in this region. Specific response is formed locally against these antigens and has an important role in mucosal immune defense of teat end (Asti
Furstenberg’s rosette is acting less as mechanical seal of teat canal and more as a local immune cell defense. (Avdic
Madras Red sheep (
The present study was conducted in the Department of Veterinary Anatomy, Madras Veterinary College, Chennai.
Teat samples were collected from apparently healthy, adult Madras Red ewes and Boer local she-goats (n=6 each) immediately after the slaughter from corporation slaughter house, Chennai. Fixatives such as 10 per cent neutral buffered formalin (NBF) and bouin’s fluid was used for sample fixation (Chaurasia
3 µm paraffin sections were cut and mounted on charged slides and incubated at 60-70 °C for 30 minutes. The sections were deparaffinized by two changes in xylene, dehydrated in absolute alcohol (two changes) and washed twice in distilled water. Heat mediated antigen retrieval was done using TRIS-EDTA buffer (pH 8.5 – 9.0). Then the sections were washed twice in distilled water for two minutes. Blocking of endogenous peroxidase was done with 3 per cent hydrogen peroxide for ten minutes. Then the sections were incubated in CD3 (ready to use) primary antibody in a moist chamber for one hour. Polyexcel HRP (ready to use) secondary antibody was added and incubated for 12 minutes and sections were washed three times in PBS. Diaminobenzidine (DAB) chromogen solution (1ml DAB buffer + 1 drop DAB chromogen) was added and kept for two to five minutes and washed in distilled water. Gill’s haematoxylin was used to counter stained the sections for one minute. Bluing the sections was done with running tap water for five minutes. Finally, sections were dehydrated through graded series of alcohol, cleared in xylene and mounted in synthetic mountant (Senthilkumar
In both Madras Red ewes and Boer local she-goats, the portion situated between the teat cistern and teat canal showed the presence of a modified structure called Furstenberg’s rosette. The structure was made of mucosa thrown into longitudinal folds. Under lower magnification, cross-section of teat revealed the mucosal folds occluded the teat canal in a petal-like fashion or rosette of a flower. There were about 11-13 folds observed (
Photomicrograph of the cross section of teat Boer graded local goat showing (D) Dermis, (Ep) Epidermis, (FR) Furstenberg’s rosette Masson’s trichrome × 12.5
Photomicrograph of the Furstenberg’s rosette of Madras Red ewe showing mucosal (1°) Primary folds, (2°) Secondary folds H&E × 50
The folds were named according to their position by primary and secondary folds. These folds were projected into the lumen. A similar observation was made by Ganga Naik (2015) in cows. Avdic
Photomicrograph of the Furstenberg’s rosette of Boer local goat showing lining epithelium (E) H&E × 400
Furstenberg’s rosette was lined by a bi-layered cuboidal epithelium. Mucosa below the rosette was the teat canal and it is lined by a stratified squamous keratinized epithelium. Nickerson and Akers (2011) Nigam and Tyagi (1971) reported that the teat/streak canal was lined by a stratified squamous keratinized epithelium in cows and buffalos respectively. Lamina propria was comprised connective tissue made up of collagen, elastic fibres (
Photomicrograph of the Furstenberg’s rosette region of Boer local she-goat showing elastic fibres (arrows) Verhoff’s method × 400
Longitudinal and circular smooth muscle bundles were located surrounding the Furstenberg’s rosette. In addition, a sub-epithelial layer of Furstenberg’s rosette showed the presence of large number of lymphocytes (
Photomicrograph of the Furstenberg’s rosette region of Madras Red ewe showing the lymphoid aggregation containing large number of lymphocytes (arrows) H&E × 400
Photomicrograph of the teat of Madras Red ewe showing CD3+ intraepithelial ‘T’ lymphocytes (brown coloured cells) in fold of Furstenberg’s rosette IHC (DAB) × 400
Asti
He also mentioned that presence of lymphoid aggregations were indicative of previous exposure to infections. In both ewes and she-goats, immunohistochemical staining for CD3 positive ‘T’ lymphocytes revealed the presence of intraepithelial lymphocytes in Furstenberg’s rosette (
Photomicrograph of the teat of Boer local she-goat showing CD3+ intraepithelial ‘T’lymphocytes (brown coloured cells) in fold of Furstenberg’s rosette IHC (DAB) × 400
Asti
Madras Red ewes and Boer local she-goats were the meat type breeds, mostly used for meat production in northern regions of Tamil Nadu. Even, in these animals, occurrence of mastitis and other teat infections were common. Hence, the study was conducted to explore the basic histological details and lymphoid aggregations in the area of Furstenberg’s rosette. The study results will be used to correlate with the microscopic lesions in histopathological study in different disease conditions.
The author acknowledges the Dean, Madras Veterinary College for providing the necessary facilities to carry out the study.