Regina Inês Kunz

Silkworm Sericin: Properties and Biomedical Applications

Silk sericin is a natural polymer produced by silkworm, Bombyx mori, which surrounds and keeps together two fibroin filaments in silk thread used in the cocoon. The recovery and reuse of sericin usually discarded by the textile industry not only minimizes environmental issues but also has a high scientific and commercial value. The physicochemical properties of the molecule are responsible for numerous applications in biomedicine and are influenced by the extraction method and silkworm lineage, which can lead to variations in molecular weight and amino acid concentration of sericin. The presence of highly hydrophobic amino acids and its antioxidant potential make it possible for sericin to be applied in the food and cosmetic industry. The moisturizing power allows indications as a therapeutic agent for wound healing, stimulating cell proliferation, protection against ultraviolet radiation, and formulating creams and shampoos. The antioxidant activity associated with low digestibility of sericin that expands the application in the medical field, such as antitumour, antimicrobial and anti-inflammatory agent, anticoagulant, acts in colon health, improving constipation and protects the body from obesity through improved plasma lipid profile. In addition, the properties of sericin allow its application as a culture medium and cryopreservation, in tissue engineering and for drug delivery, demonstrating its effective use, as an important biomaterial.

Nociceptive and histomorphometric evaluation of neural mobilization in experimental injury of the median nerve.

The carpal tunnel syndrome is the most common peripheral neuropathy in the upper limb, but its treatment with conservative therapies such as neural mobilization (NM) is still controversial. The aim of this study was to investigate the efficacy of the NM as treatment in a model of median nerve compression. 18 Wistar rats were subjected to compression of the median nerve in the right elbow proximal region. Were randomly divided into G1 (untreated), G2 (NM for 1 minute), and G3 (NM for 3 minutes). For treatment, the animals were anesthetized and the right forelimb received mobilization adapted to humans, on alternated days, from the 3rd to the 13th day postoperatively (PO), totaling six days of therapy. Nociception was assessed by withdrawal threshold, and after euthanasia histomorphometric analysis of the median nerve was performed. The nociceptive evaluation showed in G2 and G3 delay in return to baseline. Histomorphometric analysis showed no significant differences in the variables analyzed. It is concluded that the NM was not effective in reducing nociceptive sensation and did not alter the course of nerve regeneration.

Ação da estimulação elétrica nervosa transcutânea sobre o limiar de dor induzido por pressão

JUSTIFICATIVA E OBJETIVOS: A estimulacao eletrica nervosa transcutânea (TENS) e uma corrente de baixa frequencia, utilizada para tratamento de dor, contudo ha lacunas com respeito aos parâmetros de uso, bem como do modo de acao. O objetivo deste estudo foi investigar os efeitos da TENS, na forma burst, sobre a dor induzida por pressao. METODO: Estudo duplamente encoberto e cruzado, com 23 individuos, de ambos os sexos, alocados em grupo TENS (GT) e grupo placebo (GP). A TENS burst, com duracao de fase de 200 µs e com intensidade regulada ate o limiar motor foi aplicada em duas regioes dos nervos mediano e ulnar, ambos na regiao supracondiliana, por 15 minutos. Para avaliacao do limiar doloroso foi aplicado um dolorimetro de pressao sobre as regioes tenar e hipotenar nos seguintes periodos: antes e imediatamente apos a estimulacao, 20 minutos e 1 hora apos o termino da eletroestimulacao. RESULTADOS: Por meio da avaliacao do limiar doloroso da regiao tenar e hipotenar, observou-se que nao houve diferenca significativa quando comparados intragrupo e entre os grupos, para todos os momentos da avaliacao. CONCLUSAO: O uso de TENS na forma burst nao foi eficaz para elevar o limiar na dor induzida por pressao.

Effects of immobilization and remobilization on the ankle joint in Wistar rats

A sprained ankle is a common musculoskeletal sports injury and it is often treated by immobilization of the joint. Despite the beneficial effects of this therapeutic measure, the high prevalence of residual symptoms affects the quality of life, and remobilization of the joint can reverse this situation. The aim of this study was to analyze the effects of immobilization and remobilization on the ankle joint of Wistar rats. Eighteen male rats had their right hindlimb immobilized for 15 days, and were divided into the following groups: G1, immobilized; G2, remobilized freely for 14 days; and G3, remobilized by swimming and jumping in water for 14 days, performed on alternate days, with progression of time and a series of exercises. The contralateral limb was the control. After the experimental period, the ankle joints were processed for microscopic analysis. Histomorphometry did not show any significant differences between the control and immobilized/remobilized groups and members, in terms of number of chondrocytes and thickness of the articular cartilage of the tibia and talus. Morphological analysis of animals from G1 showed significant degenerative lesions in the talus, such as exposure of the subchondral bone, flocculation, and cracks between the anterior and mid-regions of the articular cartilage and the synovial membrane. Remobilization by therapeutic exercise in water led to recovery in the articular cartilage and synovial membrane of the ankle joint when compared with free remobilization, and it was shown to be an effective therapeutic measure in the recovery of the ankle joint.

Avaliação da força de preensão em ratos Wistar, normais e obesos, submetidos à natação com sobrecarga após compressão do nervo mediano

OBJECTIVE To verify the functionality through muscle grip strength in animals with obesity induced by monosodium glutamate (MSG) and in control animals, which suffered compression of the right median nerve, and treated with swimming with overload. METHODS During the first five days of life, neonatal Wistar rats received subcutaneous injections of MSG. The control group received a hypertonic saline solution. Forty-eight rats were divided into six groups: G1 (control); G2 (control + injury); G3 (control + injury + swimming); G4 (obese); G5 (obese + injury); G6 (obese + injury + swimming). The animals in groups G2, G3, G5 and G6 were submitted to compression of the median nerve and G3 and G6 groups were treated, after injury, with swimming exercise with load for three weeks. The swimming exercise had a progressive duration, according to the week, of 20, 30 and 40minutes. Muscle strength was assessed using a grip strength meter preoperatively and on the 3rd, 7th, 14th and 21st days after surgery. The results were expressed and analyzed using descriptive and inferential statistics. RESULTS When the grip strength was compared among assessments regardless of group, in the second assessment the animals exhibited lower grip strength. G1 and G4 groups had greater grip strength, compared to G2, G3, G4 and G6. CONCLUSION The swimming exercise with overload has not been effective in promoting improvement in muscle grip strength after compression injury of the right median nerve in control and in obese-MSG rats.

Artigo originalAvaliação da força de preensão em ratos Wistar, normais e obesos, submetidos à natação com sobrecarga após compressão do nervo medianoEvaluation of grip strength in normal and obese Wistar rats submitted to swimming with overload after median nerve compression☆

OBJECTIVE To verify the functionality through muscle grip strength in animals with obesity induced by monosodium glutamate (MSG) and in control animals, which suffered compression of the right median nerve, and treated with swimming with overload. METHODS During the first five days of life, neonatal Wistar rats received subcutaneous injections of MSG. The control group received a hypertonic saline solution. Forty-eight rats were divided into six groups: G1 (control); G2 (control + injury); G3 (control + injury + swimming); G4 (obese); G5 (obese + injury); G6 (obese + injury + swimming). The animals in groups G2, G3, G5 and G6 were submitted to compression of the median nerve and G3 and G6 groups were treated, after injury, with swimming exercise with load for three weeks. The swimming exercise had a progressive duration, according to the week, of 20, 30 and 40minutes. Muscle strength was assessed using a grip strength meter preoperatively and on the 3rd, 7th, 14th and 21st days after surgery. The results were expressed and analyzed using descriptive and inferential statistics. RESULTS When the grip strength was compared among assessments regardless of group, in the second assessment the animals exhibited lower grip strength. G1 and G4 groups had greater grip strength, compared to G2, G3, G4 and G6. CONCLUSION The swimming exercise with overload has not been effective in promoting improvement in muscle grip strength after compression injury of the right median nerve in control and in obese-MSG rats.

Effects of Low-Level Laser Therapy, 660 nm, in Experimental Septic Arthritis

The effectiveness of low-level laser therapy (LLLT) in the presence of an infectious process has not been well elucidated. The aim of the study was to evaluate the effects of LLLT in an experimental model of septic arthritis. Methods. Twenty-one Wistar rats were divided as follows: control group, no bacteria; placebo group, bacteria were inoculated; Treated group, bacteria were injected and treatment with LLLTwas performed. To assess nociception, a von Frey digital analgesimeter was applied. Synovial fluid was streaked to analyze bacterial growth. The standard strain of S. aureus was inoculated in the right knee. LLLT was performed with 660 nm, 2 J/cm2, over 10 days. After treatment, the knees were fixed and processed for morphological analysis by light microscopy. Results. It was found that nociception increases in the right knee. There was a lack of results for the seeding of the synovial fluid. The morphological analysis showed slight recovery areas in the articular cartilage and synovia; however, there was the maintenance of the inflammatory infiltrate. Conclusion. The parameters used were not effective in the nociception reduction, even with the slight tissue recovery due to the maintenance of inflammatory infiltrate, but produced no change in the natural history of resolution of the infectious process.

Association of sericin and swimming on the phenotype, motor plate, and functionality of the denervated plantar muscle of Wistar rats

Physical exercise may help maintain muscle properties and functional improvement after peripheral nerve lesion, which may be enhanced by using biocompatible substances, such as sericin. The aim of this study was analyse the effect of sericin associated with swimming exercise on the phenotype, innervation, and functionality of the plantar muscle of Wistar rats. Forty randomly divided adult rats were used in five groups of eight animals: control, injury, sericin, exercise, exercise and sericin. The application of sericin was done on the spot, 100 μL, shortly after nerve compression. Three days after sciatic nerve compression, the swimming and swimming and sericin groups were submitted to physical swimming exercise for 21 days. Afterwards, the animals were euthanised and the plantar muscle was dissected and submitted to histochemical and histoenzymological techniques. The grip strength test did not show alterations in muscular functionality, and the control presented greater muscle mass in relation to the other groups, the same did not occur for muscle length. Polymorphic neuromuscular junctions were detected in the groups, although without significant morphometric alterations of the area, major and minor diameters. The percentage of type I fibres was lower in the lesion group and there was no difference in fibres IIa and IIb between groups. The area of fibres I, IIa and IIb remained constant between groups. Sericin biopolymer combined with swimming exercise did not affect plantar muscle function, submitted to experimental axonotmosis, whose contractile properties were altered by nerve injury.

Obesidade materna associada ao tratamento com Losartan: efeitos sobre o esqueleto da prole de ratas

Introducao: a obesidade, uma pandemia mundial, e uma condicao clinica que se relaciona com diversas comorbidades, como a hipertensao arterial, que pode ser farmacologicamente tratada com Losartan. A complexidade da obesidade associada ao uso de medicamentos poderia programar metabolicamente diversos sistemas orgânicos, como o tecido osseo. Objetivo: verificar os potenciais efeitos da obesidade associada ao uso de Losartan como programador metabolico sobre parâmetros histomorfometricos do tecido osseo da prole. Metodologia: Foram utilizadas ratas Wistar, divididas em grupos controle (CTL), que recebeu racao padrao e agua; e tratado (CAF+ LOS), que recebeu dieta de cafeteria ad libitum e Losartan diariamente por meio de gavagem. Aos 70 dias de vida as ratas foram submetidas ao cruzamento com machos da mesma especie. A partir dos 21 dias de vida, a prole foi alimentada com racao padrao ate os 100 dias de vida, quando 8 femeas de cada grupo foram pesadas e eutanasiadas. Foram coletadas e pesadas as gorduras retroperitoneal e perigonadal. Em seguida, as tibias direitas foram coletadas e submetidas ao processamento histologico de rotina para microscopia de luz, com posterior analise de parâmetros histomorfometricos. Resultados: houve um aumento estatisticamente significativo no acumulo de gordura perigonadal nas ratas do grupo CAF+LOS, bem como menor area do canal medular da tibia nestas ratas em relacao ao grupo CTL. Conclusao: a obesidade induzida por dieta de cafeteria associada ao uso de Losartan programou a prole por meio do aumento no acumulo de gordura perigonadal e reducao da area do canal medular da tibia.

Ação da vanilina ( Vanilla planifolia ) sobre a morfologia dos músculos tibial anterior e sóleo após lesão nervosa

RESUMO Objetivo Avaliar a acao da vanilina (Vanilla planifolia) sobre a morfologia dos musculos tibial anterior e soleo apos lesao nervosa periferica. Metodos Ratos Wistar foram divididos em quatro grupos, com sete animais cada, sendo Grupo Controle, Grupo Vanilina, Grupo Lesao e Grupo Lesao + Vanilina. Os animais dos Grupos Lesao e Grupo Lesao + Vanilina foram submetidos a lesao nervosa por meio da compressao do nervo isquiatico, e os Grupos Vanilina e Grupo Lesao + Vanilina foram tratados diariamente [...]ABSTRACT Objective To evaluate the action of vanillin (Vanilla planifolia) on the morphology of tibialis anterior and soleus muscles after peripheral nerve injury. Methods Wistar rats were divided into four groups, with seven animals each: Control Group, Vanillin Group, Injury Group, and Injury + Vanillin Group. The Injury Group and the Injury + Vanillin Group animals were submitted to nerve injury by compression of the sciatic nerve; the Vanillin Group and Injury + Vanillin Group, were treated daily with oral doses of vanillin (150mg/kg) from the 3rd to the 21st day after induction of nerve injury. At the end of the experiment, the tibialis anterior and soleus muscles were dissected and processed for light microscopy and submitted to morphological analysis. Results The nerve compression promoted morphological changes, typical of denervation, and the treatment with vanillin was responsible for different responses in the studied muscles. For the tibialis anterior, there was an increase in the number of satellite cells, central nuclei and fiber atrophy, as well as fascicular disorganization. In the soleus, only increased vascularization was observed, with no exacerbation of the morphological alterations in the fibers. Conclusion The treatment with vanillin promoted increase in intramuscular vascularization for the muscles studied, with pro-inflammatory potential for tibialis anterior, but not for soleus muscle.