Tumor necrosis factor
α immunoreactivity in the walls of the middle cerebral artery
and microvessels following subarachnoid hemorrhage
(SAH). Images represent (A) sham, SAH + vehicle and SAH + U0126, 2 days after SAH; (B) sham, SAH + vehicle and SAH + U0126, 3 days after SAH; and (C) sham and SAH, 4 days after SAH. There was a significant increase in TNFα protein level in the SMCs of the MCA after SAH + vehicle as compared to sham-operated rats at 2, 3 and 4 days with maximum at 3 days. Treatment with U0126, given at 6 h after induced SAH, prevented the increased protein expression at 2 and 3 days. In addition, treatment with U0126 decreased the TNFα immunoreactivity in the microvessels (white arrows) after induction of SAH at 2 and 3 days. (D) Bar graph showing semiquantification of fluorescence intensity for TNFα in MCA. Data are presented as the mean percentage relative to sham ± SEM; n = 5. *P <0.05, **P <0.01.