Cellular and physiological upregulation of inducible nitric oxide synthase, arginase, and inducible cyclooxygenase in wound healing

Abstract

Wound repair is regulated by overlapping cellular, physiological and biochemical events. Prostaglandins and nitric oxide have been a focus for inflammation research particularly since the discovery of their inducible isoforms nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Study of the cellular expression of iNOS and COX-2 and arginase which competes with iNOS for its substrate, in an in vivo model of wound healing could reveal important roles for these enzymes in the physiological progression of wound repair. Adult male rats received full thickness dermal wounds which were harvested at different times. Protein levels and activities of the enzymes were assessed by western blot and biochemical assays respectively. The cellular distribution and the colocalization were assessed by immunostaining. The protein levels and activities of iNOS, arginase, and COX-2 increased only during the inflammatory phase of wound. Immunocytochemistry showed that the three enzymes were coexpressed and the main cellular source was inflammatory cells mainly macrophages. iNOS was induced at the wound site and was the earliest to increase significantly (p < 0.05) for only up to 3 days postwounding. However, arginase and COX-2 significant (p < 0.05) upregulation started at a later time points and continued for up to 14 days postwounding. Therefore iNOS, compared with arginase and COX-2, showed a temporal difference in expression during wound healing which could be explained by their products being required at different stages of the healing process.The coordinated expression of the three enzymes at different time points could account for the physiological progression of the healing process.

A possible role for inducible arginase isoform (AI) in the pathogenesis of chronic venous leg ulcer

“…Wound healing is a multiphase process regulated by cellular and biochemical events at the site of injury (Abd El-Aleem, Abdelwahab, Am-Sherief, & Sayed, 2019;Broughton, Janis, & Attinger, 2006).…”

“…Healing requires integration between different cell types (Broughton et al, 2006;El Kahi et al, 2009;Sarrazy, Billet, Micallef, Coulomb, & Desmouliere, 2011;Singh et al, 2004); keratinocytes for epidermal proliferation (Pastar et al, 2014), fibroblasts and myofibroblasts for collagen synthesis (Abd El-Aleem et al, 2019;Sarrazy et al, 2011), and endothelial cells for angiogenesis (Kolluru, Bir, & Kevil, 2012).…”

Doxycycline Hyclate Modulates Antioxidant Defenses, Matrix Metalloproteinases, and COX‐2 Activity Accelerating Skin Wound Healing by Secondary Intention in Rats

“…The skin healing process is known as acute or chronic, according to its duration and nature [7]. During a chronification process, there is persistent activation of COX way and neutrophils and macrophages release cytokines and chemokines, which attract more cells to the location of the inflammation and promote oxidative stress in the repairing tissue [10,11]. The excess of proinflammatory mediators increases the peroxide of hydrogen (H 2 O 2 ) and oxide nitric content, which accelerate the peroxidation of lipids and proteins [12].…”

“…Oxidative Medicine and Cellular Longevity limited to the initial stages of wound healing. From COX-2 activity, intense PG levels are detected after skin injuries, which are potent proinflammatory effectors that attract immune cells, stimulate fibroblast, and endothelial cell proliferation and metabolism in the wound area [11]. COX-2 played a central and regulatory role in the arachidonic acid pathway, by regulating hemostasis and inflammation [67] and directly impacting the development of the subsequent phases of wound healing [68].…”

Soluble Fraction from Lysates of Selected Probiotic Strains Differently Influences Re-Epithelialization of HaCaT Scratched Monolayer Through a Mechanism Involving Nitric Oxide Synthase 2

“…However, further studies are needed both to identify probiotics or any combinations of them in terms of therapeutic efficacy and to fully define the underlying mechanisms. In this regard, it seems quite surprising that, according to our knowledge, there is no literature data about possible involvement in the pro-healing mechanisms activated by some probiotics, of nitric oxide (NO), one of the most important players in the regulation of the wound repair process [25][26][27][28]. The levels of NO metabolites were shown to correlate with the healing trajectory indicating the tendency of recovery or exacerbation [29].…”