67: Early Melittin and Apitoxin Acupuncture as an Analgesic Intervention for Neuropathic Pain in Females

Topic: Basic Science
Subtopic: Pain category (ICD-11), Chronic neuropathic pain, , , , , , , , , , Behavioral studies

Background and Aims: Neuropathic pain is one of the most prevalent chronic pain, affecting approximately 8% of the global population, with women representing 60% of neuropathic pain cases. Sex-related differences in pain sensibility and analgesic efficacy of drugs are reported. However, basic searches, pre-clinical assays, and clinical trials are still mostly conducted in males. This accounts for the poor understanding of the painful mechanism, hormonal influence, and the effectiveness of new compounds in females. Considering that the treatment of chronic pain remains a challenge, mainly for women, we currently focus on delaying its establishment and the pain onset using apitoxin and melittin.

Methods: Neuropathy was induced in Wistar female (CEUA 9080280324) rats (3-6 weeks, 180– 200g), by the chronic constriction of the sciatic nerve (CCI). Initially, 9 treatments were realized, starting on the 1 day after CCI induction. The treatments were performed with apitoxin (1 mg/kg) and mellitin (0,6 mg/kg) applied as pharmacopuncture at the Suzanli (ST36) acupoint to evaluate the ability to delay pain onset. Pain nociceptive behaviors were assessed using the stimulus-evoked tests (Acetone Test and Von Frey filaments test) and weight-bearing. The estrous cycle was analyzed by vaginal lavage in the same period of the behavioral assessments.

Results: Evaluating the mechanical test, the treatment with melittin and apitoxin promotes analgesia for 86 days, and the weight-bearing recovery was observed for 88 days. In thermal assessment, apitoxin was not effective in to promote thermal analgesia, while melittin induced analgesia for 7 days. Repetitive administration was not able to induce tolerance. The pain threshold of female rats in baseline conditions and 1 day after CCI surgery was not influenced by the estrous cycle.

Conclusions: In conclusion, melittin demonstrated potential to induce analgesic effects on mechanical and thermal sensitivity in chronic pain model in rodents, both in acute and chronic phases.

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Presenting Author: Mariana Gianfrancesco Rodrigues Leonor
Submitting Author: Mariana Leonor

Senior Author: Gisele Picolo

IASP 2026 Global Year theme of Neuropathic Pain: Yes

• Ana Maria Boaventura De Oliveira - Butantan Institute
• Tamires Cunha Almeida - Butantan Institute
• Morena Brazil Martins Sant Anna - Butantan Institute
• Rafael Marques Porto - Butantan Institute
• Gisele Picolo - Butantan Institute