N-tosyl- l-phenylalanyl-chloromethylketone reduces hypoxic–ischemic brain injury in rat pups

Abstract

N-tosyl- l-phenylalanyl-chloromethylketone (TPCK) in vitro blocks apoptotic pathways leading to cell death. We wished to see if TPCK would reduce brain injury in vivo. Seven-day-old rat pups had the right carotid artery ligated and then received either vehicle or TPCK (5 to100 mg/kg i.p.). They were then given 8% oxygen for 2.25 h. Twenty-two days later, the cerebral hemispheres were weighed to determine the reduction in size in the right hemisphere. TPCK decreased the reduction in right hemisphere weight from 15±3% (vehicle, n=20), to 4±2% (10 mg/kg, n=19, P<0.01). TPCK reduced the number of cells staining for DNA breaks 3 days after injury from 1729±275 mm −2 (vehicle, n=8) to 550±236 mm −2 (10 mg/kg TPCK, n=9, P<0.01), decreased the amount of DNA fragmentation 3 days after injury by gel electrophoreses (20 mg/kg, n=16, P<0.01) and eliminated the increase in nitric oxide metabolites 6 h after injury (vehicle 1.5±0.4, n=10; and 20 mg/kg TPCK 0.0±0.1 nM/mg protein, n=10, P<0.001). TPCK pretreatment in the newborn rat model of hypoxic–ischemic brain injury reduces DNA fragmentation, nitric oxide production and brain injury.