[Protective effect and mechanism of pretreatment with curcumin on infectious brain edema in rats]

Curcumin is a natural compound extracted from the spice tumeric, possessing both anti-inflammatory antioxidant, and anti-carcinogenic effect, is a potent stimulator of the stress-induced expression of heat shock protein 70 kd (HSP70).

To study the protective effect of pretreatment with curcumin against infectious brain edema in rats, and investigate its mechanism by assessing the free radical, cytokine and HSP70 expression of the brain.

An animal model of infectious brain edema induced by injecting pertussis bacilli (PB) through carotid artery was used. SD rats were randomly divided into five groups: (1) Normal control group (NS group, n = 9); (2) Infectious brain edema group (PB group, n = 12); (3) DMSO control group (DMSO group, n = 9); (4) HS pretreatment group (HS group, n = 9); (5) Curcumin pretreatment group (CUR group, n = 13). The water content (WC), Na(+) and K(+) content in brain tissue were measured. The content of malondialdehyde (MDA) and super oxide dismitase (SOD) were assessed by chemical colorimetry. The levels of tumor necrosis factor alpha (TNF-alpha) and interleukin-1beta (IL-1beta) were detected by ELISA. The HSP70 expression was examined by Western blot analysis.

(1) The WC and Na(+), MDA, TNF-alpha and IL-1beta were increased in PB group compared with NS group (P < 0.01); they were decreased in HS and CUR groups compared with PB group (P < 0.01 or P < 0.05). (2) The content of SOD was decreased in PB group than in NS group (P < 0.05), and was increased in HS and CUR group Compared with PB group, (P < 0.05). (3) Western blot analysis showed that the band density areas of HS, CUR and PB groups were higher than those in NS and DMSO groups, especially in CUR group (P < 0.01).

Pretreatment with curcumin showed a protective effect against infectious brain edema in rats. The effect might be associated with antioxidant, inhibition of the activity of cytokines and inducing expression of HSP70 by curcumin.