Macrophages are activated in the rat anterior pituitary under chronic inflammatory conditions. (23rd March 2021)

• Record Type: Journal Article
• Authors: Yagasaki, Yuki; Katayama, Yoko; Kinoshita, Yoko; Nagata, Tomonari; Kawakami, Yoriko; Miyata, Mariko
• Is Part Of: Neuroscience letters. Volume 748(2021)
• Publication Date: 2021-03-23
• Subjects: Macrophages -- Folliculostellate cells -- IL-1β -- Chronic inflammatory pain model -- Chronic neuropathic pain model; Neurology -- Periodicals; Neurology -- Periodicals; Research -- Periodicals; Neurologie -- Périodiques; Neuroanatomie -- Périodiques; Neuropharmacologie -- Périodiques; Neurophysiologie -- Périodiques; Neurology; Periodicals; Electronic journals; 617.48
• DOI: 10.1016/j.neulet.2021.135688
• Languages: English
• ISSNs: 0304-3940

Abstract

Highlights: We immunohistochemically identified macrophages and folliculostellate (FS) cells in the anterior pituitary (AP). Macrophages increased in chronic inflammatory pain but not in neuropathic pain, whereas FS cells were unaffected in both conditions. The level of IL-1β in the AP increased in the chronic inflammation model. Most of the IL-1β-positive cells were macrophages, not FS cells. Abstract: In the anterior lobe of the pituitary gland (AP), non-endocrine cells regulate hormone secretion by endocrine cells. However, the functions of non-endocrine cells in the AP during chronic pain are largely unclear. Here, we show that macrophages, but not folliculostellate (FS) cells, were selectively increased in the AP in the complete Freund's adjuvant (CFA)-induced chronic inflammatory pain model in rats. In addition, IL-1β expression was increased in the AP, and the IL-1β-immunopositive cells were identified as macrophages. On the other hand, increased macrophage density and IL-1β expression were not detected in a neuropathic pain model induced by partial sciatic nerve ligation (PSL). Furthermore, we found c-Fos expression specifically in the somatotrophs under the chronic inflammatory pain condition. Because IL-1β promotes growth hormone (GH) synthesis and release, our results suggest that AP macrophage contributes to GH release through IL-1βduring chronic inflammatory pain.