[Requirement of LRG in endotoxin-mediated brain protection]

To explore the protective mechanism of LPS pretreatment in a rat model of cerebral ischemia-reperfusion injury.

Sixty-six male Spraque-Dawley rats were randomly divided into a sham group (n=22), a control group (n=22) and a LPS group (n=22).The control group and the LPS group were subjected to focal cerebral isehmia induced by middle cerebral artery occlusion (MCAO) for 2 hours. The LPS group was pretreated with LPS for five consecutive days with the last pretreatment at 24 hours before the surgery, while the control group and the sham group were pretreated similarly with normal saline. Seventy-two hours after reperfusion, the rats were examined for neurological behavior scores and then killed to measure the infarct volumes and the brain levels of TNF-α, IL-1β, IL-6 and IL-10.

The brain levels of LRG and IL-10 in the LPS group were significantly higher than those in the control group, while obvious decrease of TNF-α, IL-1β and IL-6 was observed in the brains of the LPS group. Accordingly, the neurological behavior scores in the LPS group were better than those in the control group, whereas the infarct volumes in the LPS group were significantly smaller than those in the control group (P<0.05).

LPS pretreatment has neuroprotective effect, which involves LRG upregulation and interference in the dynamic balance of inflammatory reactions.