Therapeutic concentration of morphine reduces oxidative stress in glioma cell line

Morphine is a potent analgesic opioid used extensively for pain treatment. During the last decade, global consumption grew more than 4-fold. However, molecular mechanisms elicited by morphine are not totally understood. Thus, a growing literature indicates that there are additional actions to the analgesic effect. Previous studies about morphine and oxidative stress are controversial and used concentrations outside the range of clinical practice. Therefore, in this study, we hypothesized that a therapeutic concentration of morphine (1 μM) would show a protective effect in a traditional model of oxidative stress. We exposed the C6 glioma cell line to hydrogen peroxide (H₂O₂) and/or morphine for 24 h and evaluated cell viability, lipid peroxidation, and levels of sulfhydryl groups (an indicator of the redox state of the cell). Morphine did not prevent the decrease in cell viability provoked by H₂O₂) but partially prevented lipid peroxidation caused by 0.0025% H₂O₂) (a concentration allowing more than 90% cell viability). Interestingly, this opioid did not alter the increased levels of sulfhydryl groups produced by exposure to 0.0025% H₂O₂), opening the possibility that alternative molecular mechanisms (a direct scavenging activity or the inhibition of NAPDH oxidase) may explain the protective effect registered in the lipid peroxidation assay. Our results demonstrate, for the first time, that morphine in usual analgesic doses may contribute to minimizing oxidative stress in cells of glial origin. This study supports the importance of employing concentrations similar to those used in clinical practice for a better approximation between experimental models and the clinical setting.

Partial time use of anterior repositioning splints in the management of TMJ pain and dysfunction: a one-year controlled study

This study aimed at evaluating the effectiveness of partial use of anterior repositioning appliances in the management of TMJ pain and dysfunction when compared to stabilization splints and a control group in a one-year follow-up. Sample was initially constituted by 60 patients, randomly divided into three groups: I- stabilization splints, II- repositioning splints and III- no treatment. The whole sample was evaluated by means of TMJ and muscle palpation, mandibular AROM, analysis of occlusal contacts, joint sounds inspection and Visual Analogue Scale (VAS) for one year; 52 patients composed the final sample. A significant (after 15 days) improvement in pain report (VAS) and palpation index was found for group II (p≤0.01). The occurrence of occlusal alterations as posterior open bite or gross interferences after the splint therapy and increased muscle tenderness were not problems in this study. Similar results in joint noises reduction were observed for the entire sample. It was concluded that controlled partial use of repositioning splints is a beneficial tool in the management of intra-articular pain and dysfunction, with no risks of irreversible occlusal changes.