Intra-cerebroventricular Administration of Crocin Attenuates Sleep Deprivation-induced Hyperalgesia in Rats

Introduction: Sleep deprivation can cause hyperalgesia and interfere with analgesic treatments. The aim of the present study was to establish an obligatory sleep-abstinence model and also evaluate the effects of intracerebroventricular (ICV) injection of crocin on pain perception in Wistar rats. Methods: In this experimental study, 35 adult male Wistar rats were randomly divided into 5 groups (n=7). The intra-ventricular cannulation was done for all rats before sleep deprivation. Sleep deprivation was performed by placing animals on a chamber equipped with an automatic animated conveyor (5 s with an interval of 3 min) for 72 h. Subsequently, the sleep-deprived animals received ICV injection of saline (MOD), Morphine 10 µg (MOR), Crocin 10 ug (Cr10), and Crocin40 µg (Cr40) using a microsyringe. Besides, a non-sleep-deprived group was allocated as a Control Group (NC) and only received an ICV injection of saline. Fifteen minutes after the ICV injections, pain perception was evaluated by the hot plate test (54±0.4◦C).  Results: Compared with the NC group, latency significantly decreased in the MOD group (6.28±0.48 vs. 4.28± 0.48, p<0.0001). In comparison with the MOD group, both morphine (8.42±1.53) and crocin (7.60±1.45 for Cr10 and 8.14±0.89 for Cr40) could significantly increase latency in the sleep-deprived animals (p<0.0001). There was no statistically significant difference between the Cr10 and Cr40 (p=0.42), Cr10, and MOR (p=0.059) and Cr40 with MOR (p=0.86) groups. Conclusion: Our results indicated that crocin could attenuate hyperalgesia induced by sleep deprivation in rats.