Department of Human Anatomy, Yaroslavl State Medical University, Yaroslavl, Russia.
Department of Normal and Pathological Anatomy, Kabardino-Balkarian State University Named After H.M. Berbekov, Nalchik, Russia.
Histochem Cell Biol. 2024 Nov;162(5):385-402. doi: 10.1007/s00418-024-02322-9. Epub 2024 Aug 17.
Somatostatin (SST) is a peptide expressed in the peripheral and central nervous systems, as well as in endocrine and immune cells. The aim of the current study is to determine the percentage of SST immunoreactive (IR) neurons and their colocalization with choline acetyltransferase (ChAT), neuronal nitric oxide synthase (nNOS), neuropeptide Y (NPY), and glial fibrillary acidic protein (GFAP) in the myenteric plexus (MP) and submucous plexus (SP) of the small intestine (SI) and large intestine (LI) of rats across different age groups from newborn to senescence using immunohistochemistry. In the MP of the SI and LI, the percentage of SST-IR neurons significantly increased during early postnatal development from 12 ± 2.4 (SI) and 13 ± 3.0 (LI) in newborn rats to 23 ± 1.5 (SI) and 18 ± 1.6 (LI) in 20-day-old animals, remaining stable until 60 days of age. The proportion of SST-IR cells then decreased in aged 2-year-old animals to 14 ± 2.0 (SI) and 10 ± 2.6 (LI). In the SP, the percentage of SST-IR neurons significantly rose from 22 ± 3.2 (SI) and 23 ± 1.7 (LI) in newborn rats to 42 ± 4.0 in 20-day-old animals (SI) and 32 ± 4.9 in 30-day-old animals (LI), before declining in aged 2-year-old animals to 21 ± 2.6 (SI) and 28 ± 7.4 (LI). Between birth and 60 days of age, 97-98% of SST-IR neurons in the MP and SP colocalized with ChAT in both plexuses of the SI and LI. The percentage of SST/ChAT neurons decreased in old rats to 85 ± 5.0 (SI) and 90 ± 3.8 (LI) in the MP and 89 ± 3.2 (SI) and 89 ± 1.6 (LI) in the SP. Conversely, in young rats, only a few SST-IR neurons colocalized with nNOS, but this percentage significantly increased in 2-year-old rats. The percentage of SST/NPY-IR neurons exhibited considerable variation throughout postnatal development, with no significant differences across different age groups in both the MP and SP of both intestines. No colocalization of SST with GFAP was observed in any of the studied animals. In conclusion, the expression of SST in enteric neurons increases in young rats and decreases in senescence, accompanied by changes in SST colocalization with ChAT and nNOS.
生长抑素（SST）是一种在外周和中枢神经系统以及内分泌和免疫细胞中表达的肽。本研究的目的是使用免疫组织化学方法确定不同年龄组（从新生到衰老）大鼠小肠（SI）和大肠（LI）的肌间神经丛（MP）和黏膜下神经丛（SP）中 SST 免疫反应（IR）神经元及其与胆碱乙酰转移酶（ChAT）、神经元型一氧化氮合酶（nNOS）、神经肽 Y（NPY）和胶质纤维酸性蛋白（GFAP）的共定位百分比。在 SI 和 LI 的 MP 中，SST-IR 神经元的比例在出生后早期发育过程中显著增加，从新生大鼠的 12±2.4（SI）和 13±3.0（LI）增加到 20 日龄动物的 23±1.5（SI）和 18±1.6（LI），直到 60 日龄保持稳定。然后，2 岁老年动物中的 SST-IR 细胞比例下降到 14±2.0（SI）和 10±2.6（LI）。在 SP 中，SST-IR 神经元的比例从新生大鼠的 22±3.2（SI）和 23±1.7（LI）显著上升到 20 日龄动物的 42±4.0（SI）和 30 日龄动物的 32±4.9（LI），然后在 2 岁老年动物中下降到 21±2.6（SI）和 28±7.4（LI）。从出生到 60 日龄，MP 和 SP 中 97-98%的 SST-IR 神经元与两个肠段的 ChAT 共定位。老年大鼠中 SST/ChAT 神经元的比例下降到 MP 中的 85±5.0（SI）和 90±3.8（LI）以及 SP 中的 89±3.2（SI）和 89±1.6（LI）。相反，在幼鼠中，只有少数 SST-IR 神经元与 nNOS 共定位，但在 2 岁大鼠中，这一比例显著增加。SST/NPY-IR 神经元的比例在整个出生后发育过程中变化很大，在两个肠段的 MP 和 SP 中，不同年龄组之间没有显著差异。在任何研究动物中都没有观察到 SST 与 GFAP 的共定位。总之，肠神经元中 SST 的表达在幼鼠中增加，在衰老中减少，同时伴随着 SST 与 ChAT 和 nNOS 共定位的变化。
