ABSTRACT
Objectives: Peroxisome proliferator-activated receptors (PPARs) control wound healing processes in damaged tissues. PPAR agonists have neuroprotective effects in spinal cord injury (SCI); however, isotype-specific roles of PPARs are not well understood. Therefore, we evaluated protein expression changes for three isotypes of PPARs at different time points and locations relative to the epicenter after SCI in rats.
Methods: A 10-g rod was dropped on the spinal cord which located at the T10 vertebra of rats from a height of 6.25, 12.5, or 50 mm using New York University impactor. We collected the spinal cord at 6, 12, 24, and 72 h and 1, 3, and 5 weeks after SCI. The protein expression of PPARs was analyzed using western blot.
Results: The protein expression of PPAR-α declined gradually up to 5 weeks at the epicenter. PPAR-β/δ expression increased from 3 days to 5 weeks at the caudal region, but decreased at the epicenter in the severe injury group. PPAR-γ expression increased significantly at all regions in all three injury groups up to 5 weeks after SCI and increased to a greater extent in the severe injury group. In addition, PPAR-β/δ controlled protein expression of PPAR-α positively, and -γ negatively.
Conclusions: The present results suggest that different PPAR isotypes have varied protein expression patterns at the epicenter and in adjacent regions after SCI. Our results suggest that PPARs may have overlapping but distinct roles. These findings will be useful for further studies investigating PPARs in neurological disorders including SCI.
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Notes on contributors
Youngkyung Kim
Youngkyung Kim is a postdoctoral fellow at the department of physiology in Korea University College of Medicine. She has several publications in the pathological mechanisms after spinal cord injury. She has been interested in environmental changes at injured epicenter, and an interconnection between upper and lower segments after SCI.
Kyu-Won Park
Kyu-won Park is an orthopedist and a PhD student. He has been interested in traumatic damages following accidents. This is the first publication in a biography.
Jeonghwa Oh
Jeonghwa Oh is a physical therapist. She has been interested in therapeutics of spinal cord injury patients. This is the first publication in a biography
Junesun Kim
Junesun Kim is P.T. and Ph.D. in Physiology. She is a professor at Department of Physical Therapy Korea University College of Health Science. Her major fields of academic interest are the peripheral and central mechanisms of chronic pain, and regenerative mechanisms governing spinal cord injury. She has several publications in in peer-reviewed journals. She provides continuing education lectures regarding neurological physical therapy for SCI and mechanisms of chronic and pathologic pain to student majoring in rehabilitation science at graduate program.
Young Wook Yoon
Young Wook Yoon is M.D. and Ph.D. in Physiology. He is a professor at Department of Physiology Korea University College of Medicine. His major fields of academic interest are neural mechanisms of chronic and pathologic pain, and neuroprotective and restorative mechanisms after spinal cord injury, on which he published numerous articles in peer-reviewed journals. He has served numerous positions of research administration for Korea University.