Banca de DEFESA: LAURO JEFERSON TARGINO DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LAURO JEFERSON TARGINO DA SILVA
DATE: 30/03/2026
TIME: 14:00
LOCAL: meet.google.com/soo-ygmx-zss
TITLE:

Effects in the Hot Plate test and preservation of nerve fibers (PGP 9.5) induced by a lidocaine–capsaicin nanoemulgel in experimental diabetic neuropathy

KEY WORDS:

Diabetic Neuropathy; Diabetic Polyneuropathy;  Capsaicin; Lidocaine

PAGES: 70
BIG AREA: Ciências da Saúde
AREA: Odontologia
SUMMARY:

Distal Symmetric Polyneuropathy (DSP), a common manifestation of Diabetic Neuropathy (DN), is characterized by the loss of protective sensation and reduced intraepidermal nerve fiber density. This study investigated whether the topical application of a nanoemulgel containing lidocaine and capsaicin (FLC) is capable of modulating thermal sensitivity and promoting neuroprotection in the paws of Wistar rats in an experimental model of streptozotocin-induced diabetic neuropathy (65 mg/kg). Animals were allocated into groups treated with vehicle (CN), commercial capsaicin, or the FLC nanoemulgel, with applications performed three times daily for 15 days. Nociceptive sensitivity was assessed using the Hot Plate test (47 °C), and neural integrity was evaluated by immunohistochemistry using the pan-neuronal marker PGP 9.5 in the plantar region. Behavioral findings from the Hot Plate test (47 °C) demonstrated that the FLC nanoemulgel did not alter thermal sensitivity in healthy animals (p = 0.425), maintaining withdrawal latencies comparable to baseline values and the vehicle-treated group. This result indicates that the formulation does not interfere with physiological nociception, preserving sensory function in intact tissue. In contrast, topical application of commercial capsaicin in healthy animals significantly increased withdrawal latency compared to the control group (p < 0.05), indicating a hypoalgesic effect in normal skin. In the diabetic neuropathy model, animals exhibited increased thermal withdrawal latency compared to non-diabetic controls, confirming the presence of hypoalgesia. The vehicle-treated group (CN diabetic) maintained elevated latencies throughout the experimental period, indicating that the vehicle did not aggravate the sensory deficit. Similarly, treatment with the FLC nanoemulgel did not produce significant differences between pre- and post-treatment periods in diabetic animals (p = 0.3125), demonstrating that the formulation did not exacerbate diabetic hypoalgesia. In contrast, animals treated with commercial capsaicin showed a significant increase in withdrawal latency after treatment (p = 0.0313), indicating worsening of thermal hyposensitivity. Immunohistochemical analysis revealed that FLC significantly increased PGP 9.5 immunoexpression, with elevated % DAB-positive area (p < 0.01) and H-score (p < 0.01). Additionally, an increase in nerve fiber density per mm² (p < 0.05) and a reduction in the axonal fragmentation index (p < 0.01) were observed, indicating improved integrity of nerve terminals. Effect size analysis (Hedges’ g) confirmed large magnitudes (|g| > 0.8) for all structural and molecular parameters evaluated. In conclusion, the FLC nanoemulgel did not exacerbate the progressive sensory deficit associated with diabetes and was able to prevent peripheral nerve fiber degeneration. Its superiority over commercial capsaicin may be related to the formulation design, in which lidocaine is present in the aqueous phase and capsaicin is dispersed in the oil phase, which may favor a more gradual release of active compounds and a more progressive modulation of nociceptive function. Thus, FLC represents a promising and safe therapeutic strategy for the management of diabetic neuropathy.

COMMITTEE MEMBERS:
Presidente - 2374605 - AURIGENA ANTUNES DE ARAUJO
Interno - 3486175 - CIRO DANTAS SOARES
Externo à Instituição - RICARDO DIAS DE CASTRO - UFPB