Investigation of Excitatory and Inhibitory Effects of L-Arginine and L-NAME on the thickness of the cortex and medulla of Thymus in Pregnant Rats

Subject Areas : Developmental biology of plants and animals , development and differentiation in microorganisms

SMH Noori Moogahi ¹ , ZN Sharifi ² , shabnam movaseghi ³ , عطارد السادات Mostafavinia ⁴

1 - School of medicine, Tehran University of medical sciences, Tehran, Iran
2 - Department of Anatomy & Cognitive Neurosciences, Faculty of Medicine, Tehran Medical sciences, Islamic Azad University, Tehran, Iran
3 - Department of Anatomy & Cognitive Neurosciences, Faculty of Medicine, Tehran Medical sciences, Islamic Azad University, Tehran, Iran
4 - Department of Anatomy & Cognitive Neurosciences, Faculty of Medicine, Tehran Medical sciences, Islamic Azad University, Tehran, Iran

Received: 2022-02-19 Accepted : 2022-02-19 Published : 2022-02-20

Keywords: nitric oxide, Thymus, L-arginine, Morphometry, L-NAME,

Abstract :

Considering the important role of Nitric Oxide (NO) in many biologic processes of cells and tissues including during pregnancy and its different stages, this study investigated the effects of L-Arginine as a NO precursor and L-NAME as a NO inhibitor on structural and stereological changes of the thymus in pregnant rats. In this experimental study, thirty-two female Wistar rats, aged 8 weeks and weighing 200-250g, were randomly divided into 4 groups: Control, L-Arginine (200 mg / kg), L-NAME (20 mg / kg) and L-Arginine + L-NAME; 8 rats in each group. On the 18th day of pregnancy, the rats anesthetized with ether, then, their thymus was extracted and fixed in 10% formalin. After tissue passage, the sections were stained with H&E and the histological and morphometric studies were performed. L-Arginine with its stimulative effect on NO synthesis in thymus causes to increase T-lymphocyte population, therefore thickness of cortex is increased and thickness of medulla decreased. Analysis of variance showed that the thickness of cortex and medulla of thymus in the L-Arginine group was significantly different in comparison with the control group, with p=0.000 and p=0.002, respectively. The thickness of cortex and medulla in the L-NAME group showed a significant decrease, with p=0.000, compared to the control group.