Progesterone administration modulates expressions of toil-like receptors and NF-kB after traumatic brain injury in male rats

Objective To investigate the role of progesterone in regulating expressions of toll-like receptors （TLR） and nuclear factor-kappa B （NF-kB） in the injured brain following traumatic brain injury （TBI）. Methods A total of 18 male Wistar rats were randomly divided into control group, trauma group and progesterone treatment group. Right parietal cortical contusion was made by using weight-dropping method. Rats were injected with 16 mg/kg progesterone at 1 and 6 hours and at days 1,2, 3,4 and 5 after TBI. Rats were sacrificed to extract brain samples at day 5 after trauma for measuring mRNA expressions of TLR2 and TLR4 as well as NF-kB binding activity. Results TBI could up-regulate mRNA levels of TLR2 and TLR4 and activity of NF-kB in the contusion area （P 〈0.01 ）. But, administration of progesterone following TBI exerted a contrary effects, ie, down-regulation of level of TLR2 and TLR4 and activity of NF-kB （P 〈 0.01 ）. Conclusion Progesterone may attenuate expressions of TLR2, TLR4 and NF-kB in the injured rat brain, as may be one of mechanisms that progesterone attains neural protection following TBI. Key words: Brain injuries;  Toll-like receptors;  Nuclear factor-kappa B ;  Progesterone