Comparative Histological, Histochemical and Immunohistochemical Examination of the Cranial and Caudal Gland of Each Lactating Mammary Gland Quarter of One Humped She Camel (Camelus Dromedarius)

Abstract

Studying the complete histological picture of the camel mammary gland plays a major role in understanding the variations in camel milk yield and composition. Therefore, the present study aimed to give more detailed description of the structure of the lactating dromedary she-camel mammary gland. The whole udder of 9 healthy lactating she-camels (Camelus dromedaries) was dissected of the fresh carcasses just after slaughtering. Sections were dissected out and fixed in 10% neutral buffer formalin for histological and immunohistochemical examination. Other parts were fixed in glutaraldehyde for ultrastructure examination. The gross examination of the camel mammary gland revealed that it is composed of four teats. Each teat ended by two separate orifices: cranial and caudal. Each orifice leads to a separate streak canal, separate gland cistern and separate lactating glands, cranial gland, and caudal gland. The examination of the two gland cisterns pointed out that the cranial gland cistern was significantly wider than the caudal one. The histological examination of the cranial and caudal gland revealed that the caudal gland comprised an abundant amount of interstitial connective tissue than the cranial gland. In contrast, the alveoli of the cranial gland were larger in size, more active, and stretched with secretion. The ultrastructure examination showed differences in structure and activity between the secretory cells of the two glands. The immunohistochemical examination of the lactating mammary gland showed strong expression of CK5/6 in both glands. On the other hand, the two glands showed different reactions to CK8/18, Estrogen Receptors and Progesterone Receptors (PR).