Minocycline prevents retinal inflammation and vascular permeability following ischemia-reperfusion injury.

Abstract

BACKGROUND:

Many retinal diseases are associated with vascular dysfunction accompanied by neuroinflammation. We examined the ability of minocycline (Mino), a tetracycline derivative with anti-inflammatory and neuroprotective properties, to prevent vascular permeability and inflammation following retinal ischemia-reperfusion (IR) injury, a model of retinal neurodegeneration with breakdown of the blood-retinal barrier (BRB).

METHODS:

Male Sprague-Dawley rats were subjected to 45 min of pressure-induced retinal ischemia, with the contralateral eye serving as control. Rats were treated with Mino prior to and following IR. At 48 h after reperfusion, retinal gene expression, cellular inflammation, Evan's blue dye leakage, tight junction protein organization, caspase-3 activation, and DNA fragmentation were measured. Cellular inflammation was quantified by flow-cytometric evaluation of retinal tissue using the myeloid marker CD11b and leukocyte common antigen CD45 to differentiate and quantify CD11b+/CD45low microglia, CD11b+/CD45hi myeloid leukocytes and CD11bneg/CD45hi lymphocytes. Major histocompatibility complex class II (MHCII) immunoreactivity was used to determine the inflammatory state of these cells.

RESULTS:

Mino treatment significantly inhibited IR-induced retinal vascular permeability and disruption of tight junction organization. Retinal IR injury significantly altered mRNA expression for 21 of 25 inflammation- and gliosis-related genes examined. Of these, Mino treatment effectively attenuated IR-induced expression of lipocalin 2 (LCN2), serpin peptidase inhibitor clade A member 3 N (SERPINA3N), TNF receptor superfamily member 12A (TNFRSF12A), monocyte chemoattractant-1 (MCP-1, CCL2) and intercellular adhesion molecule-1 (ICAM-1). A marked increase in leukostasis of both myeloid leukocytes and lymphocytes was observed following IR. Mino treatment significantly reduced retinal leukocyte numbers following IR and was particularly effective in decreasing the appearance of MHCII+ inflammatory leukocytes. Surprisingly, Mino did not significantly inhibit retinal cell death in this model.

CONCLUSIONS:

IR induces a retinal neuroinflammation within hours of reperfusion characterized by inflammatory gene expression, leukocyte adhesion and invasion, and vascular permeability. Despite Mino significantly inhibiting these responses, it failed to block neurodegeneration.

• Authors: Steven F Abcouwer, Cheng-Mao Lin, Sumathi Shanmugam, Arivalagan Muthusamy, Alistair J Barber, David A Antonetti
• Journal: Journal of neuroinflammation (J Neuroinflammation) Vol. 10 Pg. 149 (Dec 10 2013) ISSN: 1742-2094 [Electronic] England
• PMID: 24325836 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Neuroprotective Agents
• Minocycline

Topics

• Animals
• Blood-Retinal Barrier (drug effects, pathology)
• Capillary Permeability (drug effects)
• Fluorescent Antibody Technique
• Gene Expression (drug effects)
• Inflammation (pathology)
• Male
• Minocycline (pharmacology)
• Nerve Degeneration (pathology)
• Neuroprotective Agents (pharmacology)
• Rats
• Rats, Sprague-Dawley
• Real-Time Polymerase Chain Reaction
• Reperfusion Injury (pathology)
• Retina (drug effects, pathology)