Melatonin administration provokes the activity of dendritic reticular cells in the seminal vesicle of Soay ram during the non-breeding season

Abstract

Dendritic cells (DCs) are innate immune cells which engulf, process and present antigens to the naïve T-lymphocyte cells. However, little is known about the effect of melatonin on the DCs. The present study aimed to investigate the morphology and distribution of the DCs by transmission electron microscopy and Immunohistochemistry after melatonin administration. A total of 8 out of 15 adult ram was randomly selected to receive the melatonin implant and the remaining 7 animals received melatonin free implants. DCs showed positive immunoreactivity for CD117, S-100 protein and CD34. There is an obvious increase in the number of the positive immunoreactive cells to CD3, estrogen receptor alpha and progesterone in the treated groups. The expression of CD56 and MHCII in the DCs was abundant in the treated groups. The ultrastructure study revealed that melatonin exerts a stimulatory effect on the DCs which was associated with increment in the secretory activity of DCs. The secretory activity demarcated by an obvious increase in the number of mitochondria, cisternae of rER and a well-developed Golgi apparatus. The endosomal- lysosomal system was more developed in the treated groups. A rod-shaped Birbeck granule was demonstrated in the cytoplasm of the melatonin treated group. DCs were observed in a close contact to telocytes, T-Lymphocytes, nerve fibers and blood vessels. Taken together, melatonin administration elicits a stimulatory action on the DCs and macrophages through increasing the size, the number and the endosomal compartments which may correlate to increased immunity.

Developmental stages and growth of the proventriculus of post‐hatching Muscovy duck: Light and electron microscopic study

“…open image with CMEIAS Color Segmentation, then select "Process" from the menu items and subsequently choose "Negative image" (Gross, Reddy, & Dazzo, 2010). This program was used by some authors (Abd-Elhafeez, Abou-Elhamd, Abdo, & Soliman, 2020; Abd-Elhafeez, Abou-Elhamd, & Soliman, 2020; Abd-Elhafeez, Hassan, & Hussein, 2021).…”

Endocrine, Stemness, Proliferative, and Proteolytic Properties of Alarm Cells in Ruby-Red-Fin Shark (Rainbow Shark), Epalzeorhynchos frenatum (Teleostei: Cyprinidae)

“…Negative images were performed by using CMEIAS Color Segmentation, which is a free, improved computing technology. This has been done by the following steps: open image with CMEIAS Color Segmentation, then select “Process” from the menu items and subsequently choose “Negative image" (Gross et al, 2010; Abdel-Hakeem et al, 2019; Mustafa, 2019; Soliman et al, 2020; Abd-Elhafeez et al, 2021).…”

Potential and Possible Therapeutic Effects of Melatonin on SARS-CoV-2 Infection

“…Moreover, it was demonstrated that SARS-CoV-2 receptor binding domain (RBD) binds to bat angiotensin-converting enzyme 2 (ACE2) with lower affinity than to human ACE2 [ 33 ]. On the other hand, it has been recently shown that melatonin administration stimulates the activity of dendritic reticular cells and macrophages through increasing the size, number, and endosomal compartments which may correlate to increased immunity; melatonin activates the proliferation and maturation of all immune cells including T and B lymphocytes, granulocytes, and monocytes [ 34 ]. Based on these data we can speculate that the high levels of this molecule can be beneficial for antiviral immunity.…”

“…Animal studies Stimulates dendritic cells and macrophages 1 g (subcutaneous implant) [34] Decreases the levels of IL-6, TNF-α, leptin 1 mg/kg [55] Inhibits the activation of the NLRP3 inflammasome; reduces the level of IL-1β 30 mg/kg [65] Inhibits NF-κβ and down-regulates MMP-3 3 mg/kg [66,67] Reduces the levels of Hsp70e, CRP, IL-6 and TNF-α 200 mg/kg [68] Decreases oxidative stress after lung irradiation by enhancing the regulation of catalase, superoxide dismutase, glutathione, NADPH-oxidase 2 and 4, and by reducing the level of malondialdehyde 100-200 mg/kg [75] Reduces bleomycin-induced experimental lung fibrosis and decreases transforming growth factor-β1-induced fibrogenesis in lung fibroblasts 5 mg/kg [76] No lethality was observed 800 mg/kg […”