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.

Cells of the rectum of Bombyx mori affected by experimental inoculation with Alphabaculovirus.

Bombyx mori is an insect whose cocoon is used in the sericulture industry, which is an important activity in parts of southern Brazil. When parasitized by Bombyx mori nucleopolyhedrovirus (BmNPV) of the genus Alphabaculovirus (alphaBV), it develops nuclear polyhedrosis disease. In Brazil, an alphaBV was isolated from larvae of B. mori and various target tissues were identified. However, how this geographic viral isolate affects the rectum of silk moths was unknown. The rectum, a component of the cryptonephric system, acts to absorb water and mineral salts, and its importance for the metabolic balance of insects provoked interest in analyzing how it is affected by BmMNPV infection. Fifth instar B. mori larvae were inoculated with a viral suspension, and from the second to the ninth day post-inoculation, segments of the rectum (anterior and anal canal) were examined using light microscopy. The cryptonephric epithelial cells in the anterior region revealed no evidence of infection. However, from the fifth day post-inoculation, cells of the anal canal showed cytopathologies characteristic of alphaBV. Infection of the anal canal and other surrounding tissues led to tissue disorganization, with accumulation of polyhedra in the perinephric space and compartmentalization of the cryptonephric system, promoting changes in the fecal pellets, signalling physiological changes. These observations contribute to our understanding of the infectious cycle of BmMNPV in B. mori.

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.

Bombyx mori pylorus infection by Alphabaculovirus.

Alphabaculovirus is an entomopathogenic virus genus that infects Bombyx mori, which is known as the Bombyx mori multiple nucleopolyedrovirus (BmMNPV). This virus is polyorganotrophic, and a series of tissues are known as targets; however, there is currently no information regarding infection in the pylorus, the segment of the hindgut that is present in the midgut transition and is responsible for food passage control. Thus, in the present study, we aimed to analyze infection of the B. mori pylorus by BmMNPV. To do so, hybrid B. mori larvae were inoculated with a viral suspension of BmMNPV, and segments of the intestine containing the pylorus and its subdivisions, the posterior interstitial ring (PIR), pyloric cone, and pyloric valve, were dissected and processed for light microscopy on different days post inoculation. The results showed that B. mori pylorus subdivisions respond differently to infection, and the anterior area of the PIR is susceptible with these cells being the secondary infection targets. Cytological analysis revealed the presence of viroplasm in the hypertrophic nucleus, followed by the formation and development of viral polyhedra. Cytolysis occurred at the end of the infectious cycle, thereby releasing polyhedra and enabling the spread of the disease. There was no evidence of BmMNPV infection in the posterior area of the PIR, cone, or pyloric valve. These results will contribute to greater understanding of the virus infectious cycle, whose consequent epizootic disease can negatively impact this economically important insect that is used in silk production in Brazil.

Morphology of the Pylorus of Bombyx mori (Linnaeus) (Lepidoptera: Bombycidae).

The pylorus is a segment of the hindgut of great morphological diversity, which is subdivided into the posterior interstitial ring, pyloric cone, and pyloric valve. There is no morphological information on Bombyx mori (L.) hybrids, which is an insect of economic interest to Brazil. Consequently, this study aimed to analyze the morphology of the pylorus of hybrid larvae of fifth instars of B. mori from crossbreeding of Chinese and Japanese races. These were anesthetized, and the pylorus was fixed and processed by light microscopy and scanning electron microscopy. The pylorus presented as a separate compartment, consisting of a simple epithelium, with large variation in cell morphology, covered on the luminal side by an intima with specializations in some areas, the spicules. The musculature was formed by bundles of striated muscle fibers in longitudinal and circular arrangement. These fibers were multinucleated with central and peripheral nuclei, operating in peristalsis. The morphology of the pylorus is a reflection of functional dynamism, and this study provided a better understanding of its physiology, which promotes the regulated movement of the bolus, preventing reflux and directing it towards the ileum in the formation of fecal pellets.

Virucidal evaluation of sodium dichloroisocyanurate formulation against nucleopolyhedroviruses of silkworm / Avaliação antiviral do formulado de sódio dicloroisocianurato contra o nucleopoliedrovírus do bicho-da-seda

This study evaluated the effectiveness of a disinfectant with low corrosive action and which is not toxic to the environment, the sodium dichloroisocyanurate formulation, on the Bombyx mori nucleopolyhedrovirus (BmNPV). For this, 5th-instar B. mori silkworm larvae were divided into four experimental groups of 4 replicates with 15 larvae each, totalling 60 larvae per group. The groups were fed with mulberry (Morus sp.) leaf discs containing: BmNPV treated with the disinfectant, untreated BmNPV, only the disinfectant, and water (control). The results showed that the disinfectant does not inactivate the BmNPV and also exerts a negative effect on the insect"s resistance.

O estudo avaliou a eficiência de um desinfetante que apresenta baixa ação corrosiva e que não é tóxico ao meio ambiente, o formulado de sódio dicloroisocianurato, sobre o nucleopoliedrovírus Bombyx mori (BmNPV). Para tanto, lagartas do bicho-da-seda, B. mori, de 5º instar foram divididas em quatro grupos experimentais, 4 repetições com 15 lagartas cada, totalizando 60 lagartas por grupo. Os grupos foram alimentados com discos foliares de amoreira (Morus sp.) contendo: o BmNPV tratado com o desinfetante (solução 1); o BmNPV não tratado (solução 2); apenas o desinfetante (solução 3); e água (solução 4, controle). Os resultados mostraram que o desinfetante não inativa o BmNPV e também exerce efeito negativo na resistência do inseto.

Virucidal evaluation of sodium dichloroisocyanurate formulation against nucleopolyhedroviruses of silkworm / Avaliação antiviral do formulado de sódio dicloroisocianurato contra o nucleopoliedrovírus do bicho-da-seda

This study evaluated the effectiveness of a disinfectant with low corrosive action and which is not toxic to the environment, the sodium dichloroisocyanurate formulation, on the Bombyx mori nucleopolyhedrovirus (BmNPV). For this, 5th-instar B. mori silkworm larvae were divided into four experimental groups of 4 replicates with 15 larvae each, totalling 60 larvae per group. The groups were fed with mulberry (Morus sp.) leaf discs containing: BmNPV treated with the disinfectant, untreated BmNPV, only the disinfectant, and water (control). The results showed that the disinfectant does not inactivate the BmNPV and also exerts a negative effect on the insect"s resistance.(AU)

O estudo avaliou a eficiência de um desinfetante que apresenta baixa ação corrosiva e que não é tóxico ao meio ambiente, o formulado de sódio dicloroisocianurato, sobre o nucleopoliedrovírus Bombyx mori (BmNPV). Para tanto, lagartas do bicho-da-seda, B. mori, de 5º instar foram divididas em quatro grupos experimentais, 4 repetições com 15 lagartas cada, totalizando 60 lagartas por grupo. Os grupos foram alimentados com discos foliares de amoreira (Morus sp.) contendo: o BmNPV tratado com o desinfetante (solução 1); o BmNPV não tratado (solução 2); apenas o desinfetante (solução 3); e água (solução 4, controle). Os resultados mostraram que o desinfetante não inativa o BmNPV e também exerce efeito negativo na resistência do inseto.(AU)

Evaluation of rats´ soleus muscle submitted to remobilization protocol with therapeutic ultrasound associated with static stretching

Despite the deleterious effects, immobilization, is still often used in the treatment of musculoskeletal disorders, even with the occurrence of muscular atrophy, its reversal is a major challenge to rehabilitation. The aim of this study was evaluate the tropism of rats soleus muscle submitted to remobilization with static stretching, preceded by ultrasound, thermal and non thermal. We used 28 rats divided into four groups: G1‑immobilized and remobilized with static stretching, G2-remobilized with stretching preceded by ultrasound 1.0 W.cm–²; G3 – ultrasound at 0.5 W.cm–² , G4 – ultrasound with 0.2 W.cm–². All animals were immobilized in plantarflexion, producing shortening of the right soleus muscle for 15 days. For the groups subjected to remobilization with ultrasound doses were used according to the group, for 3 minutes, for 10 days with an interval of 2 days after the 5th treatment. After treatment with ultrasound (or not for the G1), the animals were subjected to 3 sets of 30 seconds, with 30 seconds interval between them, of static stretching of the soleus. The soleus were dissected, weighed and processed for preparation of histological slides in cross section, and evaluated the smallest diameter of 100 fibers per muscle. There was significant reduction in weight between left and right muscles in all groups, for diameters G3 showed no difference. Conclusion: stretching with or without ultrasound, was unable to reverse the deleterious effects of immobilization on muscle weight, but in the mean dose there was protective effect on the diameter of the fibers.

Silkworm salivary glands are not susceptible to Bombyx mori nuclear polyhedrosis virus.

A nuclear polyhedrosis virus isolated from infected Bombyx mori, BmNPV, was used to inoculate silkworms to determine salivary gland cell susceptibility. The salivary gland was removed from infected silkworms at different times post-inoculation and examined by light microscopy. The salivary gland cells did not exhibit any signs of BmNPV infection; however, fat body and tracheal cells, used as positive controls, showed characteristic cytopathological changes caused by BmNPV infection, which confirmed inoculum viability. The morphological distribution of tracheal branches and the basal lamina, which serves as a barrier to viral penetration, are apparently involved in this resistance to infection.

Molecular markers in commercial Bombyx mori (Lepidoptera: Bombycidae) hybrids susceptible to multiple nucleopolyhedrovirus.

The silkworm Bombyx mori L. is particularly susceptible to virus diseases, especially B. mori nucleopolyhedrovirus (BmNPV). Disease resistance, along with high productivity, are important selection criteria for developing commercial hybrids of B. mori. We used bioassays and molecular markers linked to susceptibility/resistance to baculovirus infection to analyze the response of commercial B. mori hybrids from two companies to a geographic isolate of B. mori multiple nucleopolyhedrovirus (BmMNPV) from Paraná state in Brazil. Both of these commercial lines were highly susceptible to BmMNPV, with death rates of 92 and 94%. A polymorphic fragment of approximately ~350 bp, associated with susceptibility, and an ~800-bp fragment, associated with resistance to BmMNPV, were detected in all specimens. An additional fragment of ~480 bp, recently identified by our research team as a BmMNPV genomic sequence, was detected in the infected silkworms and could be used as a molecular marker for the diagnosis of nucleopolyhedrovirus infection.