Growth factor and cytokine regulation in ventral cervical spinal cord following C2 hemisection in rats

Abstract

Large shifts in growth factor and cytokine expression have been reported in several models of spinal injury. However, published reports seldom specify changes in spinal motor areas of the ventral horn, particularly in segments below the injury. Understanding injury‐induced changes in these molecules will help define abnormalities in the molecular environment that underlie spontaneous functional recovery and/or alter the response to therapeutic intervention. Thus, we studied changes in the expression of growth factors and inflammatory mediators in the spinal ventral horn after C2 hemisection (C2HS) or sham surgery in male Lewis rats 1‐28 days post‐injury. Relative changes in BDNF, VEGFA, TNF‐α and TrkB protein levels at the site of injury and near the phrenic motor nucleus (C4) were quantified by densitometry and expressed as a percentage of time‐matched sham rats. Surprisingly, no protein measured was changed 14 or 28 days post‐C2HS. BDNF levels were increased in C2 ventral horn 1 and 3 days post‐C2HS (p<0.01), but not in C4. TNF‐α increased 1 day post‐C2HS in both C2 and C4 (p<0.05), but was only marginally elevated 3 days post‐C2HS (p=0.058). Thus, despite traumatic spinal injury, BDNF and TNF‐α expression only transiently increase in the cervical ventral horn whereas other growth factors/receptors studied are unaffected by injury.Support by NIH HL69064 and HL007654 (JW)Grant Funding SourceNIH HL007654