Effect of chrysin on nociception in formalin test and serum levels of noradrenalin and corticosterone in rats

Abstract

Objective: The levels of corticosterone and noradrenalin as the two nociception modulators modify after stress condition. The propose of current study was to investigate the effect of chrysin on formalin-induced nociceptive behaviors and serum levels of corticosterone and noradrenalin in rats.

Materials and methods: Pain was induced by applying 20 μL of 5% formalin in distilled water in the subplantar of the right hind paw. Chrysin (50, 100 and 150 mg/kg, intraperitoneally (i.p.) was administered 60 min before formalin injection. Morphine (10 mg/kg, i.p.) was administered 30 min before formalin injection. The control group received the same volume of saline by i.p. injection 30 min before formalin injection.

Results: Chrysin treatment can significantly decrease formalin-induced pain in rat in a dose-dependent manner. Chrysin (150 mg/kg) significantly inhibit the first phase (P < 0.01), whereas, the all concentration of chrysin were affected on the later phase of formalin-induced pain (P < 0.05). Chrysin could significantly attenuate the content of corticosterone and noradrenalin in the serum versus to the control rats (P < 0.01).

Conclusion: The current study confirms that the chrysin decreased the nociceptive behaviors in the formalin test and indicate a correlation with decrease in serum corticosterone and noradrenalin levels.

Keywords: Chrysin; corticosterone; nociception; noradrenalin.

Figure 1

Analgesic effect of the chrysin (CH) on the (A) early phase and (B) late phase in formalin test in rats. Sham operated (Sham), Negative control group (C), positive control group (M), CH (50 mg/kg) - treated rats (CH1), CH (100 mg/kg) - treated rats (CH2) and CH (150 mg/kg) - treated groups (CH3) (n = 8, for each group). Values are the means ± SEM for eight rats in each group. Significantly different from Negative control group (C) rats (*: P < 0.05, **: P < 0.01, ***: P < 0.001). Significantly different from positive control group (M) rats (+: P < 0.05, ++: P < 0.01, +++: P < 0.001). Significant difference between CH1 vs CH2 and CH3 groups (#: P < 0.05, ##: P < 0.01). Significant difference between CH2 vs. CH3 groups (&: P < 0.05).

Figure 2

Effect of chrysin (CH) on serum noradrenalin concentration of rats. Sham operated (Sham), Negative control group (C), positive control group (M), CH (50 mg/kg) - treated rats (CH1), CH (100 mg/kg) - treated rats (CH2) and CH (150 mg/kg) - treated groups (CH3) (n = 8, for each group). Values are the means ± SEM for eight rats in each group. Significantly different from negative control group (C) rats (**: P < 0.01, ***: P < 0.001). Significantly different from positive control group (M) rats (++: P < 0.01, +++: P < 0.001). Significant difference between CH1 vs CH2 and CH3 groups (#: P < 0.05, ###: P < 0.001). Significant difference between CH2 vs. CH3 groups ($: P < 0.05).

Figure 3

Effect of chrysin (CH) on serum corticosterone concentration of rats. Sham operated (Sham), Negative control group (C), positive control group (M), CH (50 mg/kg) - treated rats (CH1), CH (100 mg/kg) - treated rats (CH2) and CH (150 mg/kg) - treated groups (CH3) (n = 8, for each group). Values are the means ± SEM for eight rats in each group. Significantly different from negative control group (C) rats (**: P < 0.01, ***: P < 0.001). Significantly different from positive control group (M) rats (+: P < 0.05, ++: P < 0.01, +++: P < 0.001). Significant difference between CH1 vs CH2 and CH3 groups (###: P < 0.001).