Assessment of 2-chloroadenosine treatment after experimental traumatic brain injury in the rat using arterial spin-labeled MRI: a preliminary report.

C. L. Robertson, K. S. Hendrich, P. M. Kochanek, E. K. Jackson, J. A. Melick, S. H. Graham, D. W. Marion, D. S. Williams, C. Ho

Research output: Contribution to journalArticle

Abstract

Adenosine is a putative endogenous neuroprotectant. Its action at A1 receptors mitigates excitotoxicity while action at A2 receptors increases cerebral blood flow (CBF). We hypothesized that cerebral injection of the adenosine analog, 2-chloroadenosine, would decrease swelling and increase CBF early after experimental traumatic brain injury (TBI). To test this hypothesis, rats were anesthetized and subjected to TBI using a controlled cortical impact (CCI) model (n = 5/group). Immediately after injury, 2-chloroadenosine (0.3 nmole in 2 microliters) or an equal volume of vehicle were stereotactically injected lateral to the area of contusion. Using magnetic resonance imaging (MRI), in vivo spin-lattice relaxation time of tissue water (Tlobs) and CBF (arterial spin labeling) were measured in a 2-mm thick slice in the injured and non-injured hemispheres at 3-4 h after CCI. In a separate, preliminary experiment, the effect of 2-chloroadenosine injection in normal rat brain was studied. Rats (n = 2) were anesthetized and a burr hole was made for injection of 2-chloroadenosine into the same site as in the TBI model. One rat received the standard dose of 0.3 nmole and one rat received a 6 nmole injection. Tlobs and CBF studies were obtained 1.5-3.5 h after injection, using the same MRI methods as in the TBI study. In rats subjected to TBI, treatment with 2-chloroadenosine attenuated the increase in Tlobs after injury (p < 0.05 for treatment vs vehicle) in both hippocampus and cortex ipsilateral to injury. However, treatment with 2-chloroadenosine did not improve post-traumatic hypoperfusion. In normal rats, injection of 0.3 nmole of 2-chloroadenosine did not increase CBF, but the higher dosage of 6 nmole dramatically increased hemispheric CBF by 1.5-2.0-fold. The effect of local injection of 2-chloroadenosine at a dose of 0.3 nmole after experimental TBI on Tlobs presumably represents a reduction in post-traumatic edema. This reduction in edema, along with the augmentation of CBF seen in normal rats at higher dosage (6 nmole), supports a role for adenosine in neuroprotection following TBI.

Original languageEnglish (US)
Pages (from-to)187-189
Number of pages3
JournalActa neurochirurgica. Supplement
Volume76
StatePublished - 2000
Externally publishedYes

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology

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    Robertson, C. L., Hendrich, K. S., Kochanek, P. M., Jackson, E. K., Melick, J. A., Graham, S. H., Marion, D. W., Williams, D. S., & Ho, C. (2000). Assessment of 2-chloroadenosine treatment after experimental traumatic brain injury in the rat using arterial spin-labeled MRI: a preliminary report. Acta neurochirurgica. Supplement, 76, 187-189.