Analgesic effect of He-Ne (632.8 nm) low-level laser therapy on acute inflammatory pain.

OBJECTIVE: The aim of this study was to evaluate the analgesic effect of the low level laser therapy (LLLT) with a He-Ne laser on acute inflammatory pain, verifying the contribution of the peripheral opioid receptors and the action of LLLT on the hyperalgesia produced by the release of hyperalgesic mediators of inflammation. BACKGROUND DATA: All analgesic drugs have undesired effects. Because of that, other therapies are being investigated for treatment of the inflammatory pain. Among those, LLLT seems to be very promising. MATERIAL AND METHODS: Male Wistar rats were used. Three complementary experiments were done. (1) The inflammatory reaction was induced by the injection of carrageenin into one of the hind paws. Pain threshold and volume increase of the edema were measured by a pressure gauge and plethysmography, respectively. (2) The involvement of peripheral opioid receptors on the analgesic effect of the laser was evaluated by simultaneous injection of carrageenin and naloxone into one hind paw. (3) Hyperalgesia was induced by injecting PGE2 for the study of the effect of the laser on the sensitization increase of nociceptors. A He-Ne laser (632.8 nm) of 2.5 J/cm2 was used for irradiation. RESULTS: We found that He-Ne stimulation increased the pain threshold by a factor between 68% and 95% depending on the injected drug. We also observed a 54% reduction on the volume increase of the edema when it was irradiated. CONCLUSION: He-Ne LLLT inhibits the sensitization increase of nociceptors on the inflammatory process. The analgesic effect seems to involve hyperalgesic mediators instead of peripheral opioid receptors.

Avaliação clínica e histopatológica de alo-transplante de bexiga em cães / Clinical and histopathological evaluation of urinary bladder allotransplant in dogs

Testou-se a hipótese de o alo-transplante de bexiga devolver a capacidade estrutural e funcional desse órgão, usando-se 10 cães machos, saudáveis, submetidos à cistectomia parcial com preservação do trígono vesical. Utilizou-se o alo-transplante na reconstrução da vesícula urinária com acompanhamento dos animais durante 60 dias. Aos oito dias de pós-operatório, os cães apresentavam capacidade de contenção urinária e micção espontânea. Houve aumento gradativo do volume da vesícula urinária, alcançando, aos 60 dias, valores significativamente mais altos que os observados antes da cirurgia. Verificou-se integração tecidual com regeneração parcial na interface do transplante, caracterizada por reconstituição epitelial, proliferação fibroblástica, neoangiogênese e surgimento de fibras musculares lisas, aos 60 dias. Problemas como rejeição e obstrução uretral ocorreram em três cães. Conclui-se que o alo-transplante de bexiga em cães é viável e devolve a capacidade de repleção e as demais funções fisiológicas da vesícula urinária, ocorrendo regeneração parcial dos tecidos aos 60 dias de pós-operatório.

The hypothesis that urinary bladder allotransplant in dogs repairs the functional and structural capacity of this organ. Ten healthy male dogs were submitted to partial cystectomy, preserving the vesicle trigon. Allotransplant was used on the reconstruction of the urinary bladder and the animals were kept under observation for 60 days. On day seven after surgery, the dogs presented spontaneous capacity of contention and micturition. There was a gradual increase of the volume of the urinary bladder reaching to significantly higher values on day 60. Tissue integration with partial regeneration on the interface of the transplant, characterized by epithelial reconstitution, fibroblastic proliferation, neoangiogenesis and smooth muscular fibers appearance were observed on day 60. Problems as rejection and urethral obstruction occurred in three dogs. It is concluded that the allotransplant in dogs is viable, repairing the bladder capacity and other physiologic functions of the urinary bladder, although partial tissue regeneration is observed 60 days after operation.