Rose Meire Costa Brancalhão

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.

Nucleopolyhedrovirus: scanning electron microscopy technique

A simplified methodology was developed to study the geometric form of multiple Bombyx mori Nucleopolyhedrovirus by scanning electron microscopy. The virus belongs to Baculoviridae family and was isolated from the silkworm Bombyx mori (L.) (Lepidoptera: Bombycidae). The polyhedra of Nucleopolyhedrovirus were obtained from the filtrate, inoculum and hemolymph of the silkworm experimentally infected with nuclear polyhedra. This material was placed on stubs, where a copper tape was previously adhered. After dry at room temperature the virus was covered with carbon and gold. Scanning electron microscopy analysis revealed a well defined morphology for the polyhedra of multiple Bombyx mori Nucleopolyhedrovirus, making possible the mathematical study that identified it as a truncated octahedron. The form of the polyhedron can present taxonomic value, once it is specific for each viral lineage.

Cytopathological process by multiple nucleopolyhedrovirus in the testis of Bombyx mori L., 1758 (Lepidoptera: Bombycidae).

A cytopathological methodology was used to analyze infection by Bombyx mori multiple nucleopolyhedrovirus (BmMNPV), a geographic isolate of the family Baculoviridae, in the caterpillar testes of the B. mori. Japanese B. mori strain caterpillar, fifth instar, were inoculated with BmMNPV and their testes were collected and processed for light and transmission electronic microscopy. Epithelial coating cells and interfollicular septa in testes were susceptible to BmMNPV. The first evidence of infection was detected on the 6th day post-inoculation (p.i.) in the external epithelium, and on the 7th day p.i. in the internal epithelium and interfollicular septa. Cytopathological characteristics consisted of hypertrophied nuclei, the formation of virogenic stroma, and the occlusion of virions in polyhedron protein crystals in several stages of development. At the end of the infectious process, cell lysis and release of polyhedra into the extracellular medium occurred. Histopathology revealed early infection foci in the surrounding regions of tracheal insertions, thus underlining the role of the trachea as an infection-spreading organ in insects. This spreading occurs through penetration of the basal lamina, which facilitates entry of the budded virus into the testis. Additionally, an alignment of a partial sequence of the ORF 14 of the BmMNPV geographic isolate with other NPV certified the virus genera.

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.

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.

Polymorphism of alpha s1-casein gene in a dairy goat herd in the southeastern region of Brazil

Three different regions of the alphas1-casein gene (CSN1S1) were investigated to determine the frequencies of major alleles for null, low, intermediate and high milk protein expression in a herd of dairy goats raised in the southeastern region of Brazil. Genomic DNA samples were obtained from leukocytes of 145 dairy goats and regions of interest in the gene were amplified through Polymerase Chain Reaction (PCR), then evaluated in both agarose (O and E allele) and polyacrylamide gels (F allele). For better characterization of the F allele, a PCR-RFLP (PCR-Restriction Fragment Length Polymorphism) study was performed employing the endonuclease XmnI. The allelic frequencies in the herd of 62 Saanen goats studied were: CSN1S1E = 0.35; CSN1S1F = 0.30; CSN1S1O1 = 0.02; CSN1S1A+B+C = 0.30, other alleles = 0.03. In another group of 83 Alpine animals, the frequencies were: CSN1S1E = 0.48; CSN1S1F = 0.28; CSN1S1O1 = 0.01; CSN1S1A+B+C = 0.20, other alleles = 0.03. In the region of exon 9 and intron downstream, where mutations that characterize the F allele occur, it was verified that different intragenic haplotypes may exist, involving the deletion of the 23rd nucleotide in the ninth exon in addition to the insertion of 11bp on intron. These haplotypes may be used to make direct association with other alleles. Although rare, a higher number of combinations were found in this work by evaluating in conjunction the region of the insertion of 3bp in the referred intron, which may allow a higher number of associations. A complete characterization of these combinations will allow elaborating simplified protocols to identify animals concerning the alleles of CSN1S1 gene in goats.

Nucleopolyhedrovirus infected central nervous system cells of Bombyx mori (L.) (Lepidoptera: Bombycidae)

BmMNPV, a Nucleopolyhedrovirus isolated from infected Bombyx mori (L.) larvae in Paraná State--Brazil, was used to inoculate healthy 5th-instar B. mori larvae and examine the infection on central nervous system (CNS) cells. Samples of nervous tissue were removed from the infected insects, at different sampling times, and processed for cytopathology studies by light and transmission electron microscopy using routine techniques. The experiment included both inoculated and non-inoculated larvae (control). BmMNPV infection was detected on the 5th day after inoculation in CNS cells. Initially, infection was characterized by nuclear hypertrophy and the presence of virogenic stroma, in which the progeny virions were produced. Virions are enveloped and occluded into protein crystal, the polyhedra. Lyses of infected CNS cells were undetected; however, free mature polyhedra were seen in spaces inside the CNS. These polyhedra possibly came from trachea that penetrate the CNS and its cells, which are susceptible to BmMNPV and lyses after infection. We conclude that the tracheal system is responsible for disseminating BmMNPV infection in B. mori CNS and that the tracheal branches allow non-occluded virions to pass through the blood-brain barrier.

Effects of aging and maternal protein restriction on the muscle fibers morphology and neuromuscular junctions of rats after nutritional recovery.

Changes in the nutritional status of mothers may predispose their offspring to neuromuscular disorders in the long term. This study evaluated the effects of maternal protein restriction during pregnancy and lactation on the muscle fibers and neuromuscular junctions (NMJs) of the soleus muscle in the offspring of rats at 365 days of age that had undergone nutritional recovery. Wistar rats were divided into two groups: control (CG)--the offspring of mothers fed a normal protein diet (17%) and restricted (RG)--offspring of mothers fed a low protein diet (6%). After lactation, the male pups received standard chow ad libitum. At 365 days, samples of soleus muscle were collected for muscle fiber analysis (HE staining, NADH-TR reaction and ultrastructure), intramuscular collagen quantification (picrosirius red staining) and NMJs analysis (non-specific esterase technique). The cross-sectional area of type I fibers was reduced by 20% and type IIa fibers by 5% while type IIb fibers increased by 5% in the RG compared to the CG. The percentage of intramuscular collagen was 19% lower in the RG. Disorganization of the myofibrils and Z line was observed, with the presence of clusters of mitochondria in both groups. Regarding the NMJs, in the RG there was a reduction of 10% in the area and 17% in the small diameter and an increase of 7% in the large diameter. The results indicate that the effects of maternal protein restriction on muscle fibers and NMJs seem to be long-lasting and irreversible.

Treinamento aeróbico prévio à compressão nervosa: análise da morfometria muscular de ratos

INTRODUCTION: Sciatica stems from compression of the sciatic nerve and results in pain, paresthesia, decreased muscle strength and hypertrophy. Exercise is recognized in the prevention and rehabilitation of injuries, but when performed in overload, it may increase the risk of injury and subsequent functional deficit. OBJECTIVE: To evaluate effects of aerobic training prior to an experimental model of sciatic pain concerning morphometric parameters of soleus muscles of rats. MATERIALS AND METHODS: 18 rats were divided into three groups: sham (dip, 30 seconds), regular exercise (swimming, 10 minutes daily) and progressive aerobic training (swimming, progressive time from 10 to 60 minutes daily). After six weeks of exercise, rats were subjected to the experimental model of sciatic pain. On the third day after injury, they were killed and their soleus muscles were dissected, weighed and processed for histological analysis. The analyzed variables were: muscle weight, cross-sectional muscle area and mean diameter of muscle fibers. RESULTS: Statistically significant difference was observed for all groups when compared to control muscle and that submitted to sciatic injury. Intergroup analysis showed no statistically significant difference for any of the variables. CONCLUSION: Both regular physical exercise and aerobic training had no preventive or aggravating effects on the consequences of functional inactivity after sciatica.

Nociceptive and Neuronal Evaluation of the Sciatic Nerve of Wistar Rats Subjected to Compression Injury and Treated with Resistive Exercise

Background. To investigate the climb stairs resistance exercise on nociception and axonal regeneration in the sciatic nerve of rats. Methods. 24 Wistar rats were divided: control group (CG—no injury), exercise group (EG—no injury with physical exercise), lesion group (LG—injury, but without exercise), and treated group (LEG—injury and physical exercise). LG and LEG were subjected to sciatic nerve compression with hemostat. From the 3rd day after injury began treatment with exercise, and after 22 days occurs the removal of a nerve fragment for morphological analysis. Results. Regarding allodynia, CG obtained values less than EG (p = 0.012) and larger than LG and LEG (p < 0.001). Histological results showed that CG and EG had normal appearance, as LG and LEG showed up with large amounts of inflammatory infiltration, degeneration and disruption of nerve fibers, and reduction of the myelin sheath; however LEG presented some regenerated fibers. From the morphometric data there were significant differences, for nerve fiber diameter, comparing CG with LG and LEG and comparing axon diameter and the thickness of the myelin of the CG to others. Conclusion. Climb stairs resistance exercise was not effective to speed up the regenerative process of axons.