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Effects of silymarin on neuropathic pain and formalin-induced nociception in mice.

Hassani FV, Rezaee R, Sazegara H, Hashemzaei M, Shirani K, Karimi G - Iran J Basic Med Sci (2015)

Bottom Line: Regarding the fact that inflammation plays an important role in neuropathic and formalin-induced pain, it was assumed that silymarin could reduce pain.The intraperitoneal administration of silymarin (25, 50, and, 100 mg/kg) 2 hr prior to the intraplantar formalin injection suppressed the nociceptive response during the late phase of the formalin test significantly, but it was not in a dose-dependent manner.Different doses of silymarin 14 days after unilateral sciatic nerve ligation in hot plate test did not induce obvious antinociception.

View Article: PubMed Central - PubMed

Affiliation: School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.

ABSTRACT

Objectives: Based on the previous reports, silymarin can suppress nitric oxide, prostaglandin E2 (PGE2), leukotrienes, cytokines production, and neutrophils infiltration. Regarding the fact that inflammation plays an important role in neuropathic and formalin-induced pain, it was assumed that silymarin could reduce pain. The present study investigates the analgesic effects of silymarin in chemical nociception and a model of neuropathic pain.

Materials and methods: Chemical nociception was produced by injection of 20 µl of formalin (0.5% formaldehyde in saline) into the plantar region of the right hind paw. A sciatic-nerve ligated mouse was applied as the model of neuropathic pain and the antinociceptive response of silymarin was examined 14 days after unilateral nerve-ligation using the hot plate test.

Results: The intraperitoneal administration of silymarin (25, 50, and, 100 mg/kg) 2 hr prior to the intraplantar formalin injection suppressed the nociceptive response during the late phase of the formalin test significantly, but it was not in a dose-dependent manner. Different doses of silymarin 14 days after unilateral sciatic nerve ligation in hot plate test did not induce obvious antinociception.

Conclusion: Results of the present study indicated that repeated administration of silymarin prevents the formalin-induced nociceptive behavior. However, it is not effective in the treatment of sciatic neuropathic pain.

No MeSH data available.


Related in: MedlinePlus

Effect of silymarin on formalin-induced nociceptive behavior during phase I and phase II. Mice were treated with one (A), three (B) or five (C) injections of silymarin at various doses intraperitoneally. Twenty µl of formalin (0.5% formaldehyde in saline) was subcutaneously injected into the plantar region of the right hind paw 120 min after the last silymarin administration. Time of licking and/or biting the injected paw was measured during the period of 0–10 min (1st phase) and 20-40 min (2nd phase). All groups were compared to negative control group (0.5% carboxymethyl cellulose solution) according to ANOVA followed by Tukey post-hoc test. Data are shown as mean±SD. The number of animals in each group was 6 (Positive control: diclofenac)
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Figure 1: Effect of silymarin on formalin-induced nociceptive behavior during phase I and phase II. Mice were treated with one (A), three (B) or five (C) injections of silymarin at various doses intraperitoneally. Twenty µl of formalin (0.5% formaldehyde in saline) was subcutaneously injected into the plantar region of the right hind paw 120 min after the last silymarin administration. Time of licking and/or biting the injected paw was measured during the period of 0–10 min (1st phase) and 20-40 min (2nd phase). All groups were compared to negative control group (0.5% carboxymethyl cellulose solution) according to ANOVA followed by Tukey post-hoc test. Data are shown as mean±SD. The number of animals in each group was 6 (Positive control: diclofenac)

Mentions: Injection of 0.5% formalin into the hind paw of the mice caused significant early nociceptive response (licking and/or biting) and lasted for about 10 min (phase I). The second phase of the formalin test started 20-30 min after the formalin administration and lasted for about 10 min (Figure 1).


Effects of silymarin on neuropathic pain and formalin-induced nociception in mice.

Hassani FV, Rezaee R, Sazegara H, Hashemzaei M, Shirani K, Karimi G - Iran J Basic Med Sci (2015)

Effect of silymarin on formalin-induced nociceptive behavior during phase I and phase II. Mice were treated with one (A), three (B) or five (C) injections of silymarin at various doses intraperitoneally. Twenty µl of formalin (0.5% formaldehyde in saline) was subcutaneously injected into the plantar region of the right hind paw 120 min after the last silymarin administration. Time of licking and/or biting the injected paw was measured during the period of 0–10 min (1st phase) and 20-40 min (2nd phase). All groups were compared to negative control group (0.5% carboxymethyl cellulose solution) according to ANOVA followed by Tukey post-hoc test. Data are shown as mean±SD. The number of animals in each group was 6 (Positive control: diclofenac)
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4556767&req=5

Figure 1: Effect of silymarin on formalin-induced nociceptive behavior during phase I and phase II. Mice were treated with one (A), three (B) or five (C) injections of silymarin at various doses intraperitoneally. Twenty µl of formalin (0.5% formaldehyde in saline) was subcutaneously injected into the plantar region of the right hind paw 120 min after the last silymarin administration. Time of licking and/or biting the injected paw was measured during the period of 0–10 min (1st phase) and 20-40 min (2nd phase). All groups were compared to negative control group (0.5% carboxymethyl cellulose solution) according to ANOVA followed by Tukey post-hoc test. Data are shown as mean±SD. The number of animals in each group was 6 (Positive control: diclofenac)
Mentions: Injection of 0.5% formalin into the hind paw of the mice caused significant early nociceptive response (licking and/or biting) and lasted for about 10 min (phase I). The second phase of the formalin test started 20-30 min after the formalin administration and lasted for about 10 min (Figure 1).

Bottom Line: Regarding the fact that inflammation plays an important role in neuropathic and formalin-induced pain, it was assumed that silymarin could reduce pain.The intraperitoneal administration of silymarin (25, 50, and, 100 mg/kg) 2 hr prior to the intraplantar formalin injection suppressed the nociceptive response during the late phase of the formalin test significantly, but it was not in a dose-dependent manner.Different doses of silymarin 14 days after unilateral sciatic nerve ligation in hot plate test did not induce obvious antinociception.

View Article: PubMed Central - PubMed

Affiliation: School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.

ABSTRACT

Objectives: Based on the previous reports, silymarin can suppress nitric oxide, prostaglandin E2 (PGE2), leukotrienes, cytokines production, and neutrophils infiltration. Regarding the fact that inflammation plays an important role in neuropathic and formalin-induced pain, it was assumed that silymarin could reduce pain. The present study investigates the analgesic effects of silymarin in chemical nociception and a model of neuropathic pain.

Materials and methods: Chemical nociception was produced by injection of 20 µl of formalin (0.5% formaldehyde in saline) into the plantar region of the right hind paw. A sciatic-nerve ligated mouse was applied as the model of neuropathic pain and the antinociceptive response of silymarin was examined 14 days after unilateral nerve-ligation using the hot plate test.

Results: The intraperitoneal administration of silymarin (25, 50, and, 100 mg/kg) 2 hr prior to the intraplantar formalin injection suppressed the nociceptive response during the late phase of the formalin test significantly, but it was not in a dose-dependent manner. Different doses of silymarin 14 days after unilateral sciatic nerve ligation in hot plate test did not induce obvious antinociception.

Conclusion: Results of the present study indicated that repeated administration of silymarin prevents the formalin-induced nociceptive behavior. However, it is not effective in the treatment of sciatic neuropathic pain.

No MeSH data available.


Related in: MedlinePlus