[Effect of progesterone on cerebral cortex edema in rats exposed to focal ischemia/reperfusion]

To explore the effects of progesterone (PROG) on brain edema in rats.

Forty eight rats were randomly divided into 6 groups that were ischemia/reperfusion (I/R), dimethylsulfoxide (DMSO), and pretreatment, pre + posttreatment, posttreatment with PROG, and dexamethasone (DEXA) groups. The model of focal cerebral ischemia was established in rats by reversible inserting a nylon thread into the anterior cerebral artery. All rats were decapitated at 24 hours after the left middle cerebral artery occlusion (MCAO) respectively, and then brain H2O, Na+, K+, Ca2+ contents were determined.

Compared with the result in DMSO group, the content of water (P < 0.01), Na+ (P < 0.01), Ca2+ (P < 0.01) was significantly reduced, but K+ (P < 0.01) was obviously elevated in ischemia cortex in pretreatment group or pre + posttreatment group with PROG. There was also significant reduction in water (P < 0.05) and Na+ (P < 0.01), but was not significantly changed in Ca2+ (P > 0.05) and K+ (P > 0.05) in posttreatment group with PROG. The changes occurring in DEXA group were similar to those found in pretreatment group or pre + posttreatment group with PROG.

Pretreatment or pretreatment plus posttreatment with progesterone can significantly reduce brain edema in I/R.