Detection of neuron specific enolase in the lip and ear pinna of goat (Capra hircus): an immunohistochemical study

Goat skin is considered a multifunctional organ with regulatory, sensory, and protective roles. Despite the goat's economic importance and use as a model in biomedical research, it remains not given the suitable position in academic publications. This study aimed to investigate the expression of neuron-specific enolase (NSE) in the lips and ear pinnae of goats, revealing its considerable location among several sensory and structural components using immunohistochemical techniques. Also, we identified a new structure in different locations of the skin of the goat, referred to as the goat corpuscle. In the lip, NSE was strongly expressed in Ruffini corpuscles, goat corpuscles located in the skin and mucosa, and Merkel cells present in the stratum basale of the epidermis and hair follicles. NSE expression was also found in large nerves among skeletal muscle fibers, near sweat glands, sebaceous glands, and in the superficial layers of the dermis, where free nerve endings were directed. Vascular elements, including arteries, veins, and lymphatic vessels, exhibited NSE positivity in their endothelial and smooth muscle layers. Additionally, NSE was present in myoepithelial cells surrounding sweat and salivary gland secretory end pieces, fibroblasts, and telocytes in the connective tissue. In the ear, NSE was detected in Ruffini corpuscles, goat corpuscles, and a range of nerve fibers around cartilage and blood vessels. NSE expression was also observed in fibroblasts, chondroblasts, and telocytes in the cartilage and dermal tissues. This detailed mapping of NSE distribution provides new insights into its role in sensory and structural components, revealing its extensive involvement in the tissues.