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.
Keywords: Analgesic; Crocin; Pain; Secondary insomnia.
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