NDGA reduces secondary damage after spinal cord injury in rats via anti-inflammatory effects

Abstract

After spinal cord injury (SCI), a series of complex pathophysiological processes follows the initial injury. Because inflammation plays a key role in this secondary pathology damage, anti-inflammatory drug treatment may reduce secondary damage and protect neurons after SCI. Though nordihydroguaiaretic acid (NDGA) can inhibit inflammatory responses, its potential roles in neuroprotection and anti- inflammation in an SCI model have not been studied. In this study, we investigated the anti-inflammatory effects of NDGA in SCI. First, histopathological alterations were evaluated with hematoxylin/eosin (HE) and Nissl staining, showing an increased number of neurons after NDGA administration. Additionally, the extent of secondary damage was assessed by TUNEL assay and measurement of astrocyte proliferation. The data showed that the numbers of apoptotic cells and the proliferative extent of astrocytes were significantly decreased by the use of NDGA. The anti-inflammatory effect of NDGA was evaluated by measuring myeloperoxidase (MPO) levels as an indicator of neutrophil activity, macrophage/microglia numbers, and expression of inflammatory cytokines including IL-1β and TNF-α. NDGA treatment significantly decreased the MPO level and the number of macrophages/microglia. In addition, NDGA also suppressed the expression of IL-1β and TNF-α after SCI. These data suggest that anti-inflammatory action by NDGA can reduce secondary damage after SCI.