Antioxidant compounds EGB-761 and BN-520 21 attenuate heat shock protein (HSP 72 kD) response, edema and cell changes following hyperthermic brain injury - An experimental study using immunohistochemistry in the rat

Influence of the extract of Gingko biloba (EGB-761) and one of its constitu ent Gingkolide B (BN-52021) on hyperthermia induced cellular damage and hea t shock protein (HSP 72 kD) response was examined in a rat model. Rats subj ected to 4 h heat stress at 38 degrees C in a biological oxygen demand (BOD ) incubator (relative humidity 50-55%, wind velocity 20-25 cm/sec) resulted in profound edema and cell injury in many parts of the cerebral cortex, hi ppocampus, cerebellum, thalamus, hypothalamus and brain stem. Immunostainin g of HSP 72 kD showed marked upregulation in the damaged and distorted neur ons located within the edematous area. Pretreatment with EGB-761 (50 mg/kg/ day, p.o.) and BN-520 21 (2 mg/kg, p.o.) per day for 5 days significantly r educed HSP expression and attenuated cell damage. Our results show that EGB -761 and its component Gingkolide B (BN-52021) has the capacity to reduce e dema and cell injury following hyperthermia and this effect of the compound is somehow associated with a reduction in cellular stress response as evid enced with a reduction in HSP expression.