Aquaporin-4 protein expression in normal canine brains

Abstract

Background Aquaporin-4 (AQP4) is in growing recognition as potential marker for cancer progression, differentiation and therapeutic intervention. No information is available about AQP4 expression in the normal canine brain. The aim of this histopathological study is to confirm the presence of AQP4 by immunohistochemistry technique in a group of non-pathological canine brains and to describe its expression and distribution across the brain. Results Twelve non-pathological canine brains of various ages (ranging from 21 days to 17 years) and breeds were included in the study. Immunohistochemical expression of AQP4 was analyzed using formalin-fixed paraffin-embedded brain tissue sections. The findings were correlated between AQP4 expressing cells and astrocytes using glial fibrillary acidic protein (GFAP). AQP4 expression was more marked in the astrocyte foot processes of subpial, perivascular and periventricular surfaces in all specimens. The majority of the canine brain sections (9/12) presented with an AQP4 predilection for white matter tracts. Interestingly, the two youngest dogs (21 days and 3 months old) were characterized by diffuse AQP4 labelling in both grey and white matter tracts. This result may suggest that brain development and ageing may play a role in the AQP4 distribution throughout the canine brain. Conclusions This is the first study to describe immunohistochemical distribution of AQP4 in normal canine brains. The AQP4 expression and distribution in non-pathological canine brains was comparable to other species. Larger studies are needed to substantiate the influence of breed and ageing on AQP4 expression in the normal canine brain.

A Novel Gating Mechanism of Aquaporin-4 Water Channel Mediated by Blast Shockwaves for Brain Edema

“…Brain edema is one of the leading causes of death and disability worldwide, which occurs as a consequence of various cerebral injuries, , including blast induced traumatic brain injury (bTBI) . Especially, bTBI has become the “signature” injury of modern military services. − During the period 2000–2011, the number of service members suffering from bTBI in Operation Iraqi Freedom, Operation Enduring Freedom, and Operation New Dawn is as high as 229 106 . Unfortunately, more civilians are also vulnerable to such injury in accidents such as terrorist attacks and industrial explosions .…”

“…After blast impacts, the brain can develop malignant cerebral edema very quickly, on the order of an hour or so, as opposed to several hours to a day after conventional TBI . Reliable clinical treatment for blast cerebral edema remains a challenge; thus, it is urgent to reveal its mechanisms and develop more efficient therapeutic strategies. − …”