Histopathological effects of repeated 14-day administration of rizatriptan benzoate in a nitroglycerin-induced migraine rabbits model.

Abstract

Background: Migraine is one of multiple attack neurological conditions that causes moderate to severe headaches with no defined pathophysiology and few animal models.

Aim: Establishing an animal model that reproduces migraine-like action is important in medical research to identify the mechanism underlying this disorder. Additionally, it facilitates the availability and reliability of new models that may act as human surrogate models.

Method: Rabbits were divided into four groups. Negative group, migraine group, rizatriptan-nitroglycerin group, and rizatriptan group. The frequency of head scratching and the histopathological changes in the brain, liver, kidney, and heart for groups were evaluated in all groups.

Results: The behavioral characteristic of head scratching was significantly increased in the NTG group (50.4 ± 3.8) compared with the control group (9.2 ± 1.3) after 30 min of the experiment. Moreover, animals treated with rizatriptan benzoate (Riza) 10 mg/kg/orally for 14 days followed by NTG injection showed a significant decrease in the head scratch action (16.8 ± 2.3 and 17.6 ± 3.3) than the animals of NTG group (50.4 ± 3.8 and 43.6 ± 2.3) after 30 min and 60 min, respectively. Furthermore, animals treated with Riza alone showed no statistical differences in the head scratches (7.8 ± 1.3, 9.2 ± 0.8, 10.6 ± 1.1 and 9.6 ± 1.3, respectively) during the 120 min of the experiment, compared with the control group. Histopathological alterations in the brain of rabbits that received NTG showed severe diffuse dilated and engorged blood vessels. These changes were also recorded in the liver and kidney of this group. This marked vasodilation of blood vessels and central and portal veins confirms the successful induction of migraine in the rabbit model. In contrast, animals treated with Riza for 14 days demonstrated substantially less vascular dilation following NTG injection. No significant pathological lesions were observed in animals treated with Riza.

Conclusion: The current study successfully established a rabbit model of migraine using a single dose of NTG to induce migraine-like behavior. Moreover, pre-treatment with rizatriptan benzoate for fourteen days significantly reduced the symptoms of migraine and histopathological changes in different organs.