Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, 791-0295, Japan.
Department of Animal Science, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh.
Cell Tissue Res. 2018 Aug;373(2):439-457. doi: 10.1007/s00441-018-2835-9. Epub 2018 Apr 14.
Salivary glands produce various neurotrophins that are thought to regulate salivary function during normal and pathological conditions. Prosaposin (PSAP) is a potent neurotrophin found in several tissues and various biological fluids and may play roles in the regulation of salivary function. However, little is known about PSAP in salivary glands. As the functions of salivary glands are diverse based on age and sex, this study examines whether PSAP and its receptors, G protein-coupled receptor 37 (GPR37) and GPR37L1, are expressed in the salivary glands of rats and whether sex and aging affect their expression. Immunohistochemical analysis revealed that PSAP and its receptors were expressed in the major salivary glands of rats, although their expression varied considerably based on the type of gland, acinar cells, age and sex. In fact, PSAP, GPR37 and GPR37L1 were predominantly expressed in granular convoluted tubule cells of the submandibular gland and the intensity of their immunoreactivity was higher in young adult female rats than age-matched male rats, which was more prominent at older ages (mature adult to menopause). On the other hand, weak PSAP, GPR37 and GPR37L1 immunoreactivity was observed mainly in the basal layer of mucous cells of the sublingual gland. Triple label immunofluorescence analysis revealed that PSAP, GPR37 and GPR37L1 were co-localized in the basal layer of acinar and ductal cells in the major salivary glands. The present findings indicate that PSAP and its receptors, GPR37 and GPR37L1, are expressed in the major salivary glands of rats and their immunoreactivities differ considerably with age and sex.
唾液腺产生各种神经营养因子，这些因子被认为在正常和病理条件下调节唾液功能。前导丝氨酸蛋白酶原（PSAP）是一种存在于多种组织和各种生物液中的有效神经营养因子，可能在调节唾液功能中发挥作用。然而，关于唾液腺中的 PSAP 知之甚少。由于唾液腺的功能因年龄和性别而异，本研究检查了 PSAP 及其受体 G 蛋白偶联受体 37（GPR37）和 GPR37L1 是否在大鼠唾液腺中表达，以及性别和年龄是否影响其表达。免疫组织化学分析显示，PSAP 和其受体在大鼠主要唾液腺中表达，尽管其表达因腺体类型、腺泡细胞、年龄和性别而异。事实上，PSAP、GPR37 和 GPR37L1 主要在颌下腺的颗粒迂曲管细胞中表达，并且在年轻成年雌性大鼠中的免疫反应性强度高于同龄雄性大鼠，在老年（成年到更年期）更为明显。另一方面，在舌下腺的粘液细胞的基底层观察到较弱的 PSAP、GPR37 和 GPR37L1 免疫反应性。三重标记免疫荧光分析显示，PSAP、GPR37 和 GPR37L1 在主要唾液腺的腺泡和导管细胞的基底层共定位。本研究结果表明，PSAP 和其受体 GPR37 和 GPR37L1 在大鼠主要唾液腺中表达，其免疫反应性随年龄和性别有很大差异。
