Assessments of Reactive Astrogliosis Following CNS Injuries - Animal Models of Acute Neurological Injuries: Injury and Mechanistic Assessments - page 58

a transgenic mouse in which the expression of the enzyme
herpes simplex virus-thymidine kinase (HSV-TK) is targeted to
astrocytes via the mouse GFAP promoter. Ablation of prolifer-
ating cells is achieved by administration of the thymidine
analogue and antiviral agent ganciclovir, which inhibits DNA
synthesis and kills dividing cells ( 32 ). Ganciclovir was adminis-
tered peripherally by osmotic minipump beginning immedi-
ately after the traumatic CNS injury. Using this genetic tool to
evaluate the role of proliferating reactive astrocytes after trau-
matic SCI, they reported that ablation induced failure of
blood-brain barrier repair, extensive leukocyte infi ltration,
and increased tissue disruption, demyelination, cell death, and
motor defi cits as compared to mice without ablation of reac-
tive astrogliosis ( 29 ). Similarly in a model of TBI, moderate
controlled cortical impact in HSV-TK mice treated immedi-
ately post-injury with ganciclovir induced a signifi cant increase
in cell death and infl ammation that resulted in an increased loss
of cortical tissue as compared to control mice. Interestingly,
with severe TBI, substantial cell death and tissue loss was seen
in HSV-TK ganciclovir and control mice, but no signifi cant
differences between these groups were found. Taken together,
these data suggest that ablation of proliferating reactive
astrocytes is protective in moderate TBI but has little effect on
the large lesion that develops after severe TBI ( 30 ). Thus, this
mouse model of selective ablation of proliferating reactive
astrocytes has great utility in studying the functional role of
reactive astrogliosis after CNS injury.

2. Materials

1. Phosphate-buffered saline (PBS) (pH 7.2), need ~150 ml per
adult rat and ~50 ml per adult mouse
a. For 1 L of PBS add:

2.1. Buffers for Tissue
Fixation

dH 2 O 1,000 ml

NaOH Pellets ~4-6 pellets

NaH 2 PO 4 (Monobasic) 3.40 g

Na 2 HPO 4 (Dibasic) 10.24 g

NaCl 8.76 g

KCl 0.20 g

b. Once solute is completely dissolved, then pH to 7.2.
c. Chill to 4°C before use.
d. See Note 1.