Gonadotropin-releasing hormone treatment improves locomotor activity, urinary function and neurofilament protein expression after spinal cord injury in ovariectomized rats

Abstract

It was reported that the hypothalamic decapeptide, gonadotropin-releasing hormone (GnRH) produces neurotrophic effects and that the spinal cord possesses GnRH receptors. The aim of the present study was to determine whether administration of GnRH improves locomotor activity, urinary function and neurofilament (NFs) protein expression after spinal cord injury (SCI) in ovariectomized rats. SCI was induced by balloon inflation model resulting in paraplegia. Locomotion was evaluated according to the Basso, Beattie, and Bresnahan Scale. Rats were subjected to bladder compression, twice daily until bladder reflex was established. NFs of 68, 160 and 200 kDa from spinal cords were analyzed by electrophoresis. GnRH (60 μg/kg) or physiologic NaCl solution was administered at 1 day after SCI and then daily for 15 days and the functional evaluation was realized for 5 weeks. Our results indicate that locomotor activity, restoration of urinary dysfunction and NFs expression of 160 and 200 kDa were improved in SCI animals given GnRH compared to those without treatment. These findings suggest that GnRH acts as a neurotrophic factor and may be used as a potential therapeutic agent for treatment of SCI.