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

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.

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).

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.

Our results indicated that crocin could attenuate hyperalgesia induced by sleep deprivation in rats.