Faculty Collaboration Database

Non-thermal Infrared Light Treatment of Ischemia/Reperfusion Injury and Subsequent Analysis of Macrophage Differentiation. J Vis Exp 2021 Dec 30(178)

Date

01/18/2022

Pubmed ID

35037662

DOI

10.3791/62908

Scopus ID

2-s2.0-85123654791 (requires institutional sign-in at Scopus site)   3 Citations

Abstract

Tissue damage and necrosis from inflammatory processes are a consequence of ischemia reperfusion injury (IRI). In skeletal muscle, ischemia reduces the aerobic energy capacity of muscle cells, leading to adverse biochemical alterations and inflammation. The goal of this study is to show that exposure to near-infrared light (NIR) during a period of ischemia reduces IRI by decreasing necrosis and inflammation in addition to decreasing proinflammatory M1 and increasing protective M2 macrophages. C57/Bl6 mice underwent unilateral tourniquet-induced hindlimb ischemia for 3 h followed by reperfusion for either 15 or 30 min. Mice were randomly assigned to 3 groups. Group 1 underwent IRI with 30 min reperfusion. Group 2 underwent IRI with a 15 min reperfusion. Each group consisted of 50% no-NIR and 50% NIR-treated mice with exposure of 50 mW/cm² for 5 min/1 h after tourniquet closure. Group 3 were sham animals anesthetized for 3 h omitting IRI. Laser doppler flow imaging was performed on all mice to confirm ischemia and reperfusion. Flow data were expressed as the ratio of ischemic limb and the contralateral control. The mice were euthanized after reperfusion, and the quadriceps and gastrocnemius were harvested. Immunoprecipitation and western blot of macrophage-markers CD68 (M1) and CD206 (M2) were performed and normalized to CD14 expression. The expression of the inflammatory markers CXCL1 and CXCL5 was significantly reduced by NIR in the IRI group. A significant decrease in CD68 and an increase in CD206 expression was observed in animals receiving IR and NIR. Tissue necrosis was decreased by NIR in the IRI group, as visualized by 2,3,5-triphenyltetrazolium chloride (TTC) staining. The findings demonstrate that exposure to NIR reduced IRI and improved tissue survival. NIR reduced inflammation, decreased proinflammatory M1, and increased protective M2 macrophages. Exposure to NIR reduced inflammation and enhanced regeneration, leading to tissue protection following ischemia.

Author List

Compton T, Poellinger N, Struve J, Krolikowski JG, Ninomiya JT, Weihrauch D

Author

Dorothee Weihrauch DVM, PhD Research Scientist II in the Anesthesiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Inflammation
Ischemia
Macrophages
Mice
Reperfusion
Reperfusion Injury