Inflammation is defined as the response of living
tissue to injury, characterized by vasodilation,
swelling (increased vascular permeability) and
pain. The second of these cardinal signs is
demonstrable by immunostaining for plasma
proteins. In the normal central nervous system
(except in the choroid plexuses, the 5
circumventricular organs, and at the lamina
cribrosa of the optic nerve head), plasma proteins
occur only within blood vessels. If you see them
outside vessels there has been a failure of the
blood-brain barrier, which could well be due to
inflammation.

There is an artifact to avoid. Postmortem delay
can allow plasma proteins to diffuse out of the
vasculature and into some neurons and neuroglial
cells. I've seen this in human brain, and the
artifact is well documented also for animals. See:
   Mori S, Sternberger N h, Herman NM, Sternberger
l A (1991) Leakage and neuronal uptake of serum
protein in aged and Alzheimer brains: a postmortem
phenomenon with antemortem etiology. Laboratory
Investigation 64: 345-351.
   Fabian RH (1992) Poor reliability of
immunocytochemical localization of IgG in
immersion-fixed tissue from the central nervous
system. Journal of Histochemistry and
Cytochemistry 40: 987-991.
   Loberg EM, Torvik A (1992) Plasma proteins in
normal neurons: immunohistochemical studies on
autopsy material and experimental animals. Acta
pathologica et microbiologica scandinavica 100:
431-436.

A similar artifact is seen if immunohistochemistry
is attempted on unfixed cryostat sections of the
rat's brain. 
   Sparrow JR (1980) Immunohistochemical study of
the blood-brain barrier. Production of an
artifact. Journal of Histochemistry and
Cytochemistry 26: 570-572.

John Kiernan
Anatomy Dept, U.W.O.
London, Canada.
______________________
Caroline Bass wrote:
> 
> Hello,
> 
> I'm wondering if someone could suggest a marker or stain that could
> help visualize inflammation.  I am working on a project where I
> inject a virus in the brain to introduce genes in neurons.  However,
> I want to make sure that the injection itself, or the neuronal
> infection is not causing a large degree of inflammation.  Could
> someone suggest a good way to visualize this?  I imagine some sort of
> immune marker will do, perhaps mF4/80?
> 
> thanks,
> 
> Caroline
> 
> _______________________________________________
> Histonet mailing list
> Histonet@lists.utsouthwestern.edu
> http://lists.utsouthwestern.edu/mailman/listinfo/histonet

_______________________________________________
Histonet mailing list
Histonet@lists.utsouthwestern.edu
http://lists.utsouthwestern.edu/mailman/listinfo/histonet