Behavioral test for evaluation of sense of pain was performed by means of hot water test for the hind limbs after SCI (scores were obtained on Days 1, 7, 14, 21, 28, 35, 42, 49, and 56). The response to heat stimulation was measured by the latency of hind limb paw withdrawal of hot water at 50℃. Both paws of rats were kept in a hot water container, respectively. For each rat, six trials were obtained (three trials for each paw), and mean of this trials were recorded, and nonresponders were removed from the hot water container after 60 s (Kim et al., 2013; Hosseini et al., 2015).