Abstracts

Rationale: Experimental studies of erythropoetin (EPO) and interleukin 1 receptor antagonist (anakinra) in models of traumatic brain injury and stroke have demonstrated a neuroprotective effect. The objective of this study was to examine the brain gene expression effects of EPO and anakinra when administered at doses selected to produce serum concentrations obtained in clinical studies in patients. Methods: 30 rats received moderate unilateral cortical contusion injury (CCI), with another 5 rats serving as intact sham controls. EPO (2500 units/kg), anakinra (100 mg/kg) or vehicle were administered twice daily for three days with an i.p loading dose at 2 hours post-CCI and then s.c. doses at 12, 24, 36, 48, 60 and 72 hours post-injury. Groups of animals were euthanized at 24 hours, 72 hours and 7 days to examine gene expression in brain. RNA samples passed stringent quality control, were processed and submitted to microarray analysis using Affymetrix GeneChip Rat Gene 1.0 ST arrays. Microarray data analysis was performed with the Bioconductor packages limma and Ingenuity Pathway Analysis. Results: The number of differentially expressed genes (>1.5-fold up or down, p<0.05) at 24 hr, 72hr and 7 days are given in the table 1 below. At 24 hrs post-CCI, genes involved in the immune and inflammatory response, cell signaling, cell adhesion, metabolic processes and transporters were affected by both EPO and anakinra compared to vehicle. At 72 hrs and 7 days post-CCI, EPO treatment, but not anakinra, altered genes involved in inflammatory and immune response. At 72 hrs and 7 days post-CCI, EPO treatment also affected genes involved in cellular movement, cell to cell signaling and interaction and cellular growth, proliferation, function and maintenance. At 72 hrs and 7 days post-CCI, anakinra treatment effected genes involved in carbohydrate and lipid metabolism, cell to cell signaling, molecular transport and free radical scavenging. Conclusions: EPO and anakinra treatment resulted in significant effects on brain gene expression in the CCI model of traumatic brain injury when administered at doses designed to produce serum concentrations observed clinically. This research was supported by a grant from the NIH/NICHD (R01 HD061944-01).