Hypoxic preconditioning reduces ceramide formation, TNFα levels, and TNFR1 expression in the rat brain in acute cerebral ischemia

To study changes in the concentration of ceramide, the main enzymes involved in its biosynthesis, as well as TNFα and TNFR1 expression in the rat brain in acute cerebral ischemia (ACI) and hypoxic preconditioning (HP); to evaluate the relationship of these factors with animal survival and neurological deficit. Experiments were performed on 37 male white nonlinear rats weighing 180–230 g. ACI was modeled by irreversible ligation of the left common carotid artery with simultaneous reversible ligation of the right common carotid artery. The animals were divided into 3 groups: Group 1 – sham operated, Group 2 – rats with ACI, Group 3 – animals with ACI and HP. On the 3rd day of monitoring, neurologic deficit was assessed using the Garcia scale; changes in TNFα and TNFR1, ceramide, serinpalmitoyltransferase, ceramide synthase, acidic and neutral sphingomyelinases were evaluated using immunofluorescence microscopy. ACI led to increased production of ceramide in the brain with elevated levels of all enzymes studied, and was also accompanied by higher levels of TNFα and expression of its receptor TNFR1. HP contributed to the reduction of these effects: the levels of ceramide and sphingomyelinases, TNFα and TNFR1 were suppressed, the neurological deficit became less severe, and the survival of animals was improved in comparison with ACI. HP has shown its effectiveness as a method to reduce the severity of neurological disorders and increase the survival of experimental animals, to prevent changes in proinflammatory factors and ceramide level by the decrease of the main enzymes of its synthesis.

hypoxic preconditioning, cerebral ischemia, phospholipids, ceramide, TNFα, TNFR1