Abstracts

Rationale: Epilepsy patients often have reduced bone mineral density and are at an increased risk of bone fracture. Whether these bone abnormalities are due to the use of anti-epileptic drugs (AEDs) or the disease itself is unknown. For example, although decreased bone health in epilepsy patients is often attributed to the use of AEDs, seizures can also trigger a number of pathophysiological processes that have the potential to be detrimental to bone. Therefore, to assess whether bone abnormalities occur in epilepsy in the absence of AEDs, the current study investigated cortical and trabecular bone morphology in rats with chronic epilepsy. Methods: Ten-week old male Wistar rats underwent kainic acid induced-status epilepticus (SE; n = 5) for four hours or a sham procedure (n = 5). Nine weeks post-SE, rats were implanted with EEG recording electrodes and video-EEG was recorded for one week to confirm that all post-SE rats were having spontaneous seizures. Open-field testing to assess locomotion was conducted at 22-weeks post-SE. At 24-weeks post-SE, rats were killed and tibia were extracted to determine cortical and trabecular morphology by micro-computed tomography (mCT). Results: All post-SE rats had spontaneous seizures at 9-weeks post-SE, while none of the sham rats had seizures. Initial mCT analysis indicates that post-SE rats had significantly reduced trabecular bone volume fraction and trabecular number when compared with sham rats. There were no differences in total distance travelled in the open field between post-SE and sham rats suggesting that activity levels did not account for the bone differences. Further analysis of additional bone parameters is ongoing. Conclusions: All post-SE rats had spontaneous seizures at 9-weeks post-SE, while none of the sham rats had seizures. Initial mCT analysis indicates that post-SE rats had significantly reduced trabecular bone volume fraction and trabecular number when compared with sham rats. There were no differences in total distance travelled in the open field between post-SE and sham rats suggesting that activity levels did not account for the bone differences. Further analysis of additional bone parameters is ongoing. Funding: RB is supported by a grant from NINDS (NINDS RFA-NS-16-012) to TOB and SS·SS is supported by a fellowship from NHMRC.