OBJECTIVETo establish a rat model of focal lymphatic encephalopathy by partial ligation of the cerebral superficial artery for observation of the changes of Virchow-Robin spaces (VRS).

METHODSThirty male SD rats were randomized into 3 groups (n=10), including two model groups and a sham-operated group. The rats in the model groups were subjected to partial ligation of the cerebral superficial arteries under EEG monitoring to induce focal lymphatic encephalopathy, and those in the sham-operated group underwent only dissociation of the cerebral superficial artery without ligation. The rats in the two model groups were executed at 24 and 48 h, and those in the sham-operated group at 48 h following the operation, respectively. Frozen sections of the brain tissues were prepared for microscopic morphological observation and quantitative analysis of the VRS using HE staining and an image analysis system, respectively.

RESULTSEEG remained normal during the operations suggesting intact brain function. Partial ligation of the cerebral superficial arteries resulted in obvious dilation of the VRS in the cerebral cortex and subcortical medulla, and the tissues around the dilated VRSs appeared pale and structurally loosened. The two model groups showed significantly enlarged VRS areas as compared to the sham-operated group (P<0.01), but no significant differences were found in the mean VRS areas between the two model groups.

CONCLUSIONPartial dilation of the cerebral superficial artery is effective and convenient to induce focal lymphatic encephalopathy in rats, and this model can be ideal for studying focal cerebral lymph circulation.