Titanium scaffold osteogenesis in healthy and osteoporotic rats is improved by the use of low-level laser therapy (GaAlAs).

The present study aimed to assess the effects of low-level laser therapy (GaAlAs) on the bone repair process within titanium scaffolds in the femurs of healthy and osteoporotic rats. Fifty-six rats were divided into four groups: group Sh: SHAM animals that received scaffolds; group LSh: SHAM animals that received scaffolds and were subjected to laser therapy; group OV: ovarietomized (OVX) animals that received scaffolds; and group LOV: OVX animals that received scaffolds and were subjected to laser therapy. Thirty days following ovariectomy or sham surgery, scaffolds were implanted in the left femurs of all animals in the study. Immediately after opening the surgical site, the inner part of the surgical cavity was stimulated with low-level laser (GaAlAs). In addition to this procedure, the laser group was also subjected to sessions of low-level laser therapy (LLLT) at 48-h intervals, with the first session performed immediately after surgery. The rats were sacrificed at 2 and 6 weeks, time in which femur fragments were submitted for histological and histomorphometric examination, and skin tissue above the scaffold was submitted to histological analysis. At the end of the study, greater bone formation was observed in the animals submitted to LLLT. At 2 and 6 weeks, statistically significant differences were observed between LSh and Sh groups (p = 0.009 and 0.0001) and LOV and OV (p = 0.0001 and 0.0001), respectively. No statistical difference was observed when assessing the estrogen variable. On the basis of our methodology and results, we conclude that LLLT improves and accelerates bone repair within titanium scaffolds in both ovariectomized and healthy rats, when compared to animals not subjected to radiation.

Healing of normal and osteopenic bone with titanium implant and low-level laser therapy (GaAlAs): a histomorphometric study in rats.

The study investigates the influence of low-level laser therapy (LLLT) on bone healing in the femur of osteopenic and normal rats with titanium implants. Ovariectomy and control group were randomly submitted to LLLT, which was applied by gallium-aluminum-arsenium (GaAlAs) laser at the surgical site before and after placing the implant, for seven times. Histomorphometric and statistical analysis were performed. Most irradiated groups showed higher values than the nonirradiated groups. The GaAlAs infrared diode laser may improve the osseointegration process in osteopenic and normal bone, particularly based on its effects in the initial phase of bone formation.

Negative effects of alcohol intake and estrogen deficiency combination on osseointegration in a rat model.

Alcohol intake and estrogen deficiency can both affect bone physiology and have shown to have an adverse effect on dental implant therapy. However, the combination of both factors on osseointegration is unknown. The aim of this study was to evaluate osseointegration in rats fed with alcohol and presenting induced estrogen deficiency. Ninety-six female rats were divided according to diet and hormonal condition into 6 groups as follows: group Sh-W: sham (simulated ovariectomy) control, food and water ad libitum; group Sh-Et: sham, food and 20% ethanol solution ad libitum; group Sh-Su: sham, food and sucrose solution controlled to ensure an isocaloric diet in relation to Sh-Et; group Ov-W: ovariectomy, food and water ad libitum; group Ov-Et: ovariectomy, food and 20% ethanol solution ad libitum; and group Ov-Su: ovariectomy, food and sucrose solution controlled to ensure an isocaloric diet as Ov-Et. The groups were subdivided according to time of euthanasia: 30 and 45 days after placement of implants. Implant surgery was performed 1 month after ovariectomy or sham. After euthanasia, the femurs were removed and evaluated by histomorphometry. Groups Ov-Et and Ov-Su showed the lowest percentage of bone-to-implant contact. The combination of alcohol intake and estrogen deficiency, and the combination of estrogen deficiency and reduced ingestion of food can negatively affect osseointegration in rats.

Particularidades na utilização de animais no ensino e na pesquisa científica / Particularities in the use of animals in education and the scientific research

O Brasil não possui uma legislação específica que regule a criação e o uso de animais para a pesquisa e o ensino em âmbito nacional, sendo que, muitas vezes, a ética e o bom senso de nossas instituições e pesquisadores prevalecem e norteiam muitas pesquisas com animais. Descrever a regulamentação para o uso de animais na pesquisa científica no Brasil e orientar o pesquisador sobre alguns comitês do Estado de São Paulo. Para a execução deste estudo, foi realizada uma revisão sobre o tema por meio de periódicos e websites sobre legislação existente no Brasil e sobre comitês de ética para a experimentação animal do estado de São Paulo. Não existe norma sistematizadora atualizada referente à vivisseção e experimentação com animais. A única lei referente a esse tópico é de 1979 e não chegou a ser regulamentada. Leis mais recentes preocupam-se com a prática de experimentos científicos aos maus tratos de animais, na presença de tecnologia alternativa. No Estado de São Paulo, os comitês adotam fundamentos baseados no Conselho Nacional de Controle de Experimentação Animal (Concea). Ainda não existe uma regulamentação para a utilização de animais no ensino e na pesquisa científica em nosso país. As instituições vinculadas ao Colégio Brasileiro de Experimentação Animal (Cobea) deverão manter comissões de ética operantes que avaliem a necessidade de uso de animais e que, sobretudo, vigiem como o animal está sendo mantido e manipulado durante e após o término do experimento.