Increases in the phosphorylated form of caveolin-1 in the spinal cord of rats with clip compression injury.

The phosphorylation of caveolin-1, a lipid raft protein, alters cell shape, which is an important finding in the activation and migration of inflammatory cells. We studied the level of the phosphorylated form of caveolin-1 (p-caveolin-1) in the spinal cord of rats with a clip compression injury to determine whether the phosphorylation of caveolin-1 is involved in the pathogenesis of spinal cord injury. Spinal cords, sampled on days 0, 1, 4, 7, and 14 post-injury, were analyzed by Western blot and immunohistochemistry. Western blot analysis showed that the level of p-caveolin-1 significantly increased in the spinal cord at day 4 post-injury compared to the sham-operated control (p<0.05), and its increased level remained in the elevated condition until day 14 post-injury. Immunohistochemistry showed that p-caveolin-1 was mainly localized in the macrophages/activated microglia in the injured spinal cords, even though caveolin-1 was immunodetected in neurons and reactive astrocytes as well as in inflammatory macrophages. Considering these findings, we postulated that the increased level of p-caveolin-1 is involved in intracellular signaling in affected cells, particularly macrophages/activated microglia, in the course of rat spinal cord injury.