The Expression and Cellular Distribution of DOR in Two Different Animal Models During the Orofacial Neuropathic Pain
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| Year of publication | 2024 |
| Type | Appeared in Conference without Proceedings |
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| Description | Facial skeleton fractures are common injuries connected with the injury of the 2nd or the 3rd branch of the trigeminal nerve, which is manifested by anesthesia in the innervation area of the damaged branch, and the condition may progress to neuropathic pain. The incidence, risk factors, and early signs of this disability are not satisfactorily known. Opioid receptors (PORs) are widely distributed in the nervous system and play a pivotal role in analgesia. Growing evidence has shown the involvement of PORs in the modulation of orofacial pain. We studied the role of DOR during orofacial neuropathic pain using two animal models. Rats were divided into 3 groups: a group of animals that underwent unilateral ligature of the infraorbital nerve and unilateral transection of the alveolar inferior nerve, a shamoperated groups, and a control group of naive rats. After putting the animals under deep anesthesia, the left infraorbital nerve (ION) was ligated according to the modified approach of Vos et al. (1994). Two silk ligatures (6-0 Ethicon) were tied to compress the nerve. The inferior alveolar nerve (IAN) was operated on according to the model described in the publication Němec, 2020. The nerves of sham-operated rats were merely exposed without any lesions. The harvested tissues (gingival mucose, trigeminal ganglion, and trigeminal subnucleus caudalis) were processed using indirect immunohistochemical staining and immunostained sections were analyzed under an epifluorescence microscope. We found the increased level of DOR in operated groups compared to naive and DOR immunofluorescence in the IANT model was higher than in the IONL model. DOR was detected not only in the neurons but also in the glial cells within the trigeminal pathway. This study provides unique data on DOR expression in two animal models through trigeminal pathways. The activation of DOR could produce a significant analgesic effect in orofacial pain without central side effects. |
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