Mario Roberto Pontes Lisboa

Orofacial musculoskeletal pain (OMP) is a common feature of temporomandibular disorders (TMD), a group of conditions affecting the temporomandibular joint, chewing muscles, and associated structures. The etiology of muscular TMD is currently understood within a biopsychosocial model of pain, highlighting the complexity related to OMP. In this context, the objective of this study was to investigate the OMP induced by psychological/emotional stress (ES) in rats, regarding the role of the endocannabinoid system (ECS) through CB1 and CB2 receptors. Male Wistar rats were divided into Control and ES groups. OMP was induced by ES using the communication box model and evaluated through the mechanical threshold in masticatory muscles. c-Fos, CB1, and CB2 immunostaining was evaluated in the trigeminal ganglion (TG) and in the trigeminal nucleus caudalis (Sp5C). The selective CB1 or CB2 antagonist (AM251 or AM630, respectively) or the cannabinoid receptor non-selective agonist (WIN55,212-2) were administered to both groups, and the OMP was evaluated. The mechanical sensitivity of the masticatory muscles increased in the ES group, accompanied by increased c-Fos expression in the TG and Sp5C. AM251 and AM630 increased mechanical sensitivity, while WIN55,212-2 decreased the OMP. Furthermore, ES increased CB1 density in the TG and elevated both CB1 and CB2 in the Sp5C. Additionally, CB2 was increased in the masseter muscle. Thus, cannabinoid receptors played a protector role in OMP caused by ES, indicating that cannabinoid drugs or the modulation of the ECS may represent a promising approach for the treatment of OMP frequently observed in patients with TMD.

Implantes osseointegráveis são considerados o tratamento com maior índice de sucesso em Odontologia. Apesar da alta previsibilidade, a instalação de implantes ainda pode apresentar falhas técnicas e complicações biológicas, como mucosite peri-implantar e peri-implantite. Peri-implantite trata-se da infecção causada por bactérias, nos tecidos peri-implantares, que podem causar perda óssea e até perda do implante. O tratamento da peri-implantite ainda é o desbridamento mecânico de biofilme e cálculo na região do implante, porém, alguns pacientes necessitam de adjuvantes à terapia mecânica. O objetivo desse trabalho foi revisar a literatura sobre a eficácia da terapia fotodinâmica antimicrobiana (aPDT) como adjuvante à terapia mecânica para a peri-implantite. Foram selecionados artigos usando a base de dados PUBMED, com os seguintes descritores: “terapia fotodinâmica” e “peri-implantite” nos últimos 5 anos, incluindo apenas estudos clínicos. Foram incluídos 6 artigos. Com base nos achados da literatura, podemos afirmar que a aPDT, adjuvante à terapia mecânica, mostrou benefícios quanto aos parâmetros clínicos e microbiológicos no manejo da peri-implantite. Esta terapia adjuvante pode ser considerada como uma alternativa viável e eficaz, além de apresentar vantagens, como a ausência de efeitos colaterais observada no uso de antibióticos sistêmicos, e não contribuir para a resistência bacteriana.

Periodontitis and rheumatoid arthritis (RA) are inflammatory diseases characterized by chronic inflammation and bone erosion. Electroacupuncture (EA) shows anti-inflammatory and anti-resorptive effects in experimental periodontitis (EP) and in RA. It is important to investigate whether EA shows these effects in periodontal tissues in the presence of these two inflammatory diseases or not. For this, Wistar rats were divided into six groups: control (C); experimental rheumatoid arthritis (RA; bovine type II collagen-induced (CII)); experimental periodontitis (EP); RA/EP (RA + EP); EP/EA (EP treated with EA); RA/EP/EA (RA + EP treated with EA). EP was induced 21 days after RA induction and EA was performed previously and during the EP induction period, every 3 days until the 36th experimental day. The rats were euthanized on day 39. RA was evaluated by edema and the withdrawal threshold of hind paws. The maxillae were removed, and alveolar bone loss (ABL) and bone radiographic density (BRD) were evaluated. Immunohistochemical analyses for interleukins (IL)-6 and -17 and nuclear factor (NF)-κB were performed. Our results showed that EA reduced only the pain intensity in arthritic rats. Histomorphometric, macroscopic, and radiographic analyses did not show differences between the control and EP/EA groups. EA caused a reduction in ABL and BRD only in the presence of EP. EA caused a reduction in IL-6 and -17 in all groups, but NF-κB was only reduced in the arthritic rats with EP. In conclusion, EA reduced the inflammation related to periodontitis in arthritic rats but did not prevent ABL.

Sensory neuropathy is a dose-limiting side effect of oxaliplatin-based cancer treatment. This study investigated the antinociceptive effect of amifostine and its potential neuroprotective mechanisms on the oxaliplatin-related peripheral sensory neuropathy in mice. Oxaliplatin (1 mg/kg) was injected intravenously in Swiss albino male mice twice a week (total of nine injections), while amifostine (1, 5, 25, 50, and 100 mg/kg) was administered subcutaneously 30 min before oxaliplatin. Mechanical and thermal nociceptive tests were performed once a week for 49 days. Additionally, c-Fos, nitrotyrosine, and activating transcription factor 3 (ATF3) immunoexpressions were assessed in the dorsal root ganglia. In all doses, amifostine prevented the development of mechanical hyperalgesia and thermal allodynia induced by oxaliplatin (P<0.05). Amifostine at the dose of 25 mg/kg provided the best protection (P<0.05). Moreover, amifostine protected against neuronal hyperactivation, nitrosative stress, and neuronal damage in the dorsal root ganglia, detected by the reduced expression of c-Fos, nitrotyrosine, and ATF3 (P<0.05 vs the oxaliplatin-treated group). In conclusion, amifostine reduced the nociception induced by oxaliplatin in mice, suggesting the possible use of amifostine for the management of oxaliplatin-induced peripheral sensory neuropathy.