Avaliação do extrato de uncaria tomentosa na prevenção de mucosite oral induzida: estudo experimental em animais / Assessment of the uncaria tomentosa extract in the prevention of induced oral mucositis: an experimental study in animals

Mucosite é uma inflamação da mucosa oral e/ou gastrintestinal ocasionada pelo tratamento antineoplásico caracterizada por eritema, úlceras dolorosas e formação de pseudomembrana. As condutas atuais para prevenção e tratamento são paliativas. A unha-de-gato (Uncaria tomentosa) é uma planta cujo extrato tem ação imunomoduladora, antiinflamatória, antioxidante, antiviral e antimutagênica. Este trabalho visou comparar clinicamente o efeito preventivo de três doses sistêmicas de UT nas mucosites bucais induzidas por 5-FU em hamsters Sírios dourados. Foram estudados 10 animais por grupo: GC (controle), G2 (2 mg de alcalóide/kg de animal), G5 (5mg/kg) e G10 (10 mg/kg), que foram sedados e receberam a solução de UT dos dias 1 ao 5 por gavagem. Para a indução da mucosite, nos dias 4 e 6 os animais foram anestesiados e receberam 5- FU via intraperitoneal nas doses de 100mg/kg e 60mg/ kg respectivamente e no dia 6 ranhura com fio ortodôntico em ambas mucosas. Nos dias 1, 8, 10, 12, 15 os animais foram pesados, anestesiados e tiveram suas mucosas evertidas para fotografia. Dois avaliadores calibrados, sem conhecimento dos grupos, avaliaram as fotografias e deram escores para as mucosites. Todos os animais apresentaram algum grau de mucosite, a perda de peso foi significativa no grupo G10 e nas condições deste estudo, a Uncaria tomentosa não preveniu ou tratou a mucosite.

Mucositis is an inflammation of oral and/or gastrointestinal mucosa caused by antineoplasic treatment, characterized by eritema, painful ulcers and pseudo membrane formation. There is no widely accepted protocol to prevent and/or to treat mucositis. Cat's claw (Uncaria Tomentosa - UT) is a plant with immunomoduladory, antinflammatory, antioxidant and antimutagenic properties. The objective of this study was to clinically compare the effects of three systemic doses of UT in Golden Sirius hamsters that had mucositis induced by 5-fluorouracil. The experimental groups were divided according to alkaloid dose present at the aqueous extracts of UT: GC (control group), G2 (2mg of alkaloid/kg of animal), G5 (5mg/kg) and G10 (10mg/kg), being ten animals per group, in a total of forty animals. To perform the experiment, the animals received UT extracts at days 1 to 5 through gavage, and to induce the mucositis, an intraperitoneal injection of 5-FU at days 4 and 6, besides, at day 6 a mechanical trauma with orthodontic wire on both mucosas was performed.At days 1, 8, 10, 12 and 15 the animals were weighted, anesthetized and their mucosas were everted to be photographed. Two calibrated observers, with no previous knowledge of the groups evaluated the images and scored the mucositis. All animals developed mucositis, the weight loss was significant in G10, and under the conditions of this study Uncaria tomentosa did not prevent neither treated mucositis.

A simple method to measure cell viability in proliferation and cytotoxicity assays

Resazurin dye has been broadly used as indicator of cell viability in several types of assays for evaluation of the biocompatibility of medical and dental materials. Mitochondrial enzymes, as carriers of diaphorase activities, are probably responsible for the transference of electrons from NADPH + H+ to resazurin, which is reduced to resorufin. The level of reduction can be quantified by spectrophotometers since resazurin exhibits an absorption peak at 600 çm and resorufin at 570 çm wavelengths. However, the requirement of a spectrophotometer and specific filters for the quantification could be a barrier to many laboratories. Digital cameras containing red, green and blue filters, which allow the capture of red (600 to 700 çm) and green (500 to 600 çm) light wavelengths in ranges bordering on resazurin and resorufin absorption bands, could be used as an alternative method for the assessment of resazurin and resorufin concentrations. Thus, our aim was to develop a simple, cheap and precise method based on a digital CCD camera to measure the reduction of resazurin. We compared the capability of the CCD-based method to distinguish different concentrations of L929 and normal Human buccal fibroblast cell lines with that of a conventional microplate reader. The correlation was analyzed through the Pearson coefficient. The results showed a strong association between the measurements of the method developed here and those made with the microplate reader (r² = 0.996; p < 0.01) and with the cellular concentrations (r² = 0.965; p < 0.01). We concluded that the developed Colorimetric Quantification System based on CCD Images allowed rapid assessment of the cultured cell concentrations with simple equipment at a reduced cost.

Reactive oxygen species and the phagocytosis process of hemochorial trophoblast

The establishment of the hemochorial placenta requires the trophoblast to invade the endometrium and its vascular network to reach the abundant supply of maternal blood during embryo implantation. To facilitate the invasion steps and/or to provide the nutritional source for embryo development before the completion of the placenta, the trophoblast exhibits a temporally limited and very intense phagocytic activity. Despite the importance of this critical event during pregnancy, full understanding of the molecular mechanisms involved is still to be achieved. Recent findings of our laboratory show that mouse trophoblast cells are able to produce and release reactive oxygen species (ROS) to the surrounding medium, in a manner similar to activated inflammatory phagocytic cells. The aim of the present communications, is to discuss the results obtained by our group regarding the involvement of ROS in the trophoblast phagocytosis, with special attention to the underlying physiological mechanisms related to the embryo implantation.