M.G. Gomes

Effects of dantrolene on apoptosis and immunohistochemical expression of NeuN in the spinal cord after traumatic injury in rats

Dantrolene has been shown to be neuroprotective by reducing neuronal apoptosis after brain injury in several animal models of neurological disorders. In this study, we investigated the effects of dantrolene on experimental spinal cord injury (SCI). Forty‐six male Wistar rats were laminectomized at T13 and divided in six groups: GI (n = 7) underwent SCI with placebo and was euthanized after 32 h; GII (n = 7) underwent laminectomy alone with placebo and was euthanized after 32 h; GIII (n = 8) underwent SCI with dantrolene and was euthanized after 32 h; GIV (n = 8) underwent SCI with placebo and was euthanized after 8 days; GV (n = 8) underwent laminectomy alone with placebo and was euthanized after 8 days; and GVI (n = 8) underwent SCI with dantrolene and was euthanized after 8 days. A compressive trauma was performed to induce SCI. After euthanasia, the spinal cord was evaluated using light microscopy, TUNEL staining and immunochemistry with anti‐Caspase‐3 and anti‐NeuN. Animals treated with dantrolene showed a smaller number of TUNEL‐positive and caspase‐3‐positive cells and a larger number of NeuN‐positive neurons, both at 32 h and 8 days (P ≤ 0.05). These results showed that dantrolene protects spinal cord tissue after traumatic SCI by decreasing apoptotic cell death.

Histomorphometry and expression of Cdc47 and caspase-3 in hyperthyroid rat uteri and placentas during gestation and postpartum associated with fetal development

In two different experiments, the effects of hyperthyroidism on the histomorphometry and expression of Cdc47 and caspase-3 were evaluated in the uteri and placentas during gestation and postpartum. Fetal development was also evaluated during gestation. In the first experiment, 36 adult female Wistar rats were divided into two groups of 18 animals each: (1) hyperthyroid; and (2) euthyroid (control). Female rats were mated and killed at 7, 14 and 19 days of gestation. Uteri and placentas were weighed and subjected to histomorphometric and immunohistochemical evaluation to determine the expression of Cdc47 and caspase-3. Ovaries were also evaluated for weight and subjected to morphometric analysis. Fetuses were quantified and weighed individually. In the second experiment, 12 adult female Wistar rats were divided into two groups of six animals each: (1) hyperthyroid; and (2) euthyroid (control). Female rats were mated and killed 2 days postpartum. Uteri were evaluated in the same way as for the first experiment. Hyperthyroidism increased ovulation and conception rates without disturbing the size and viability of the fetuses. In the pregnant uteri, hyperthyroidism did not change the thickness of the layers or the expression of Cdc47 and caspase-3. However, in the placentas, hyperthyroidism increased the medium diameter of trophoblast cells, as well as the thickness and the expression of Cdc47 of spongiotrophoblast cells, at 14 days of gestation. During uterine involution, hyperthyroidism significantly increased the expression of Cdc47 and reduced the expression of caspase-3 in the uterine layers. In conclusion, hyperthyroidism increased the conception rate because of an ovulation gain, induced significant placental changes during pregnancy and, in the uterus, increased Cdc47 expression and decreased caspase-3 expression after parturition.

Effects of chondroitin sulfate and sodium hyaluronate on chondrocytes and extracellular matrix of articular cartilage in dogs with degenerative joint disease

Foram utilizadas amostras de cartilagem articular do femur, tibia e patela de 15 caes com doenca articular degenerativa (DAD), induzida experimentalmente. Foram constituidos tres grupos de cinco animais: grupo 1 - controle, nao medicado; grupo 2 - tratado com sulfato de condroitina e grupo 3 - tratado com hialuronato de sodio. As amostras foram processadas e coradas pelas tecnicas de HE e de azul de toluidina para avaliacao das alteracoes morfologicas, e impregnadas pelo nitrato de prata para analise da atividade metabolica e/ou proliferativa dos condrocitos, por meio da visualizacao e quantificacao de regioes organizadoras do nucleolo (NORs). Nao foram notadas diferencas significativas (P 0,05) na contagem de NORs, celulas e NORs/celula entre os grupos. As maiores contagens de NORs e de celulas no grupo tratado com hialuronato de sodio sugeriram aumento da taxa de proliferacao dos condrocitos. A maior relacao de NORs/celula obtida no grupo tratado com sulfato de condroitina sugere que essa droga estimula a atividade metabolica do condrocito, minimizando as lesoes ocorridas durante a DAD.

Sulfato de condroitina e hialuronato de sódio no tratamento da doença articular degenerativa em cães: estudo histológico da cartilagem articular e membrana sinovial

Fifteen mongrel dogs, both genders, weighting from 18 to 25kg were used and Degenerative Joint Disease (DJD) was induced through cranial cruciate ligament (CCrL) artroscopical section. After three weeks, CCrL was reconstructed by Schawalders (1989) technique. Then, dogs were distributed in three groups and the following protocols were used: group I, control, no other treatment but the CCrL reconstruction; group II received chondroitin sulfate 24mg per animal every five days, intramuscularly, in a total of six injections; and group III received sodium hyaluronate 20mg per animal every five days, intravenously, in a total of three injections. Clinical observation was done until 90 days after treatments. By that time, the articular cartilage and synovium were collected and their morphology was evaluated. In group I, the degenerative alterations of the DJD were the most intense. Thus, decrease of chondrocytes number, pannus, fibrillations, grooves, erosion, and irregular articular surface were observed on the cartilage. In group II, raise of chondrocytes number was observed, with increase of synthesis activity of matrix and decrease of lesions on the articular surface. There was an increase of chondrocytes in group III, but the cells were morphologically unviable. All the groups showed proliferation of the synovial membrane, with limpho-plasma cells infiltrated in subintim and perivascular. In groups I and III, the proliferation of synovium was abundant, with formation of pannus, flattened synoviocytes or synovium absent with granulation tissue. Those results suggest that the chondroitin sulfate stimulated the articular cartilage; decreasing or delaying the alterations of DJD, as well as, the sodium hyaluronate did not interfere on degenerative process in articular cartilage. No favorable action of these drugs in the synovial membrane was verified.

Sulfato de condroitina e hialuronato de sódio no tratamento da doença articular degenerativa experimental em cäes. Aspectos clínicos e radiológicos

The aim of this study was the evaluation of the effects of chondroitin sulfate and sodium hyaluronate in the knee joint of dogs with experimentally induced degenerative joint disease (DJD). Fifteen mongrel dogs, weighing 18 to 25kg were used. DJD was induced by cranial cruciate ligament (CCL) arthroscopical transection. After three weeks, CCL was repaired by an intrarticular technique, which uses fascia lata. The dogs were then divided into three groups as follows: group I received no other treatment, but the CCL reconstitution, group II received 24mg/animal of chondroitin sulfate/IM every five days, totaling six injections, and group III received 20mg/animal of sodium hyaluronate /IV every five days, totaling three injections. All dogs were examined clinically and radiographically for 90 days after the repairment surgery. The clinical evaluation was performed by assessment of lameness, weight-bearing, limb muscle atrophy and range of motion. The results demonstrated that the group treated with sodium hyaluronate had lower degree of lameness in comparison with other groups. The radiographic evaluation showed marginal osteophytes and subchondral bone sclerosis. These changes were more severe in the group treated with sodium hyaluronate. The better clinical results observed in this group, compared with the others, was probably due to the greater action of the drug in the synovium, decreasing the pain and lameness. Radiographic findings correlated poorly with the clinical signs in the group treated with sodium hyaluronate.

Morfologia e histoquímica da pele de ratas hipotireóideas castradas e não castradas

The cutaneous alterations of castrated and intact female Wistar rats kept under a hypothyroidism state for 120 days were studied. Two euthyroid groups, one castrated and other intact, served as controls. Ventral abdominal and dorsal thoracic skin sections were stained by HE, PAS, alcian blue, picro-sirius red-polarized light and Verhoeff. Epidermis and sebaceous glands atrophy, partial or total reduction of elastic fibrils and type III dermal collagen were observed in both hypothyroidism and castration. Delay in hair follicle growth and hyperkeratosis were only observed when deficiency of thyroid hormones was present, independent of gonadal function. The association of hypothyroidism and castration was characterized by ventral abdominal epidermis atrophy, thickening and hyperplasia of dorsal thoracic epidermis, dermis atrophy with loss of elastic fibrils and type III collagen. In conclusion, ovarian steroids or thyroid hormones deficiency modifies all the components of the skin and that the injuries are aggravated in the association hypothyroidism-castration.

Modelo experimental de trauma medular agudo produzido por aparelho estereotáxico modificado

Foram utilizados 55 ratos machos da especie Rattus novergicus, variedade Wistar, com o objetivo de propor um modelo experimental de trauma medular produzido por aparelho estereotaxico modificado, capaz de reproduzir clinicamente lesoes medulares padronizadas. Apos realizacao de laminectomia dorsal de T13, utilizou-se peso compressivo de 50,5g (25 animais - grupo I) ou 70,5g (30 animais - grupo II), durante cinco minutos, comprimindo a medula espinhal. Os animais foram assistidos durante oito dias, por meio de testes comportamentais para avaliar a sensibilidade dolorosa, a capacidade motora, o posicionamento tatil e proprioceptivo e a capacidade de manter-se em plano inclinado. No grupo I, observaram-se deficits neurologicos moderados e transitorios, que variaram entre os animais. No grupo II, foi possivel obter um trauma padronizado, caracterizado por paraplegia bilateral e simetrica dos membros posteriores, perda de propriocepcao e da sensibilidade dolorosa de todos os animais. A utilizacao do aparelho estereotaxico desenvolvido permite reproduzir clinicamente trauma medular padronizado em ratos, de maneira simples, economica e satisfatoria, o que podera proporcionar avancos nas investigacoes terapeuticas, abrangendo doencas neurodegenerativas, como e o caso do trauma medular agudo.

The ameliorating effect of dantrolene on the morphology of urinary bladder in spinal cord injured rats

In animal models of spinal cord injury (SCI), the urinary bladder can undergo significant structural and physiological alterations. Dantrolene has been shown to be neuroprotective by reducing neuronal apoptosis after SCI. Furthermore, in addition to its anti-inflammatory and antioxidant properties, it appears to have a beneficial action on voiding, once this drug acts on the external urethral sphincter relaxation. In the present study, we investigated the effects of dantrolene on urinary bladder injury that follows experimental SCI. Forty-six male Wistar rats were laminectomized at T13, and a compressive trauma was performed to induce SCI. After euthanasia, the urinary bladder was removed for gross and histological evaluation. Traumatized animals showed urinary retention with severe hemorrhagic cystitis. Injured animals treated with dantrolene had less bladder hemorrhage and inflammatory infiltrate than those treated with placebo (p<0.05). Our results demonstrate that dantrolene may protect against urinary bladder lesions that follow SCI. Treating spinal cord-injured patients with this agent may be a promising additional therapeutic strategy to alleviate the accompanying inflammatory process. The results of the current study show that dantrolene has protective effects on spinal cord contusion-induced urinary bladder injury. The impaired integrity of bladder morphology was ameliorated by dantrolene treatment.

Efeito da prednisona em lesão medular aguda experimental em ratos

ABSTRACT Twent-five rats (Rattus novergicus ) were submitted to an experimental spinal cord injury by using a 50.5g stereotaxic equipament to apply pressure on the duramater during five minutes. After the spinal cord injury, the animals were randomly distributed into five groups of five animals each: one group received placebo 8 hours after injury and the remaining four groups received prednisone at 8, 24, 48, and 120 hours after injury. Prednisone was applied at 2mg/kg dosage during five days and progressively reduced until the 26 th day. Animals were evaluated by motor capacity, proprioceptive positioning, locating reflex, inclined plan, and sensibility to pain. The animals were sacrificed 33 days after surgery for histological study of the spinal cords that revealed degeneration of the rootlets, necrosis, inflammatory foci, and reactive gliosis, with no significant differences among the treated groups. The administration of high dosages of prednisone to animals with acute spinal cord injury had no deleterious effects on neurological recovery, even when used late. Keywords: rat, prednisone, experimental models, spinal cord injury

Proliferação, apoptose e histomorfometria da glândula mamária de ratas tratadas com tiroxina na lactação e ao desmame e desenvolvimento dos filhotes

The purpose of this study was to evaluate mammary gland histomorphometry and proliferation rate and apoptosis of thyroxine-treated rats by CDC-47 and caspase-3 immunoexpression. The development of thyroxine-treated rats offspring was also evaluated. Thirty-six female rats were used, distributed in two groups, treated and non-treated with thyroxine. After 60 days of treatment, with thyroxine, rats were mated. Six animals/group were sacrificed on the 2nd and 21st days of lactation and on the 5th day after weaning. A significant difference was observed between groups only on the 5th day after weaning. Thyroxine treatment increased apoptosis rate, which was characterized by a higher caspase-3 expression in mammary epithelial cells. Thyroxine-treated mothers presented changed behavior, but there was no significant difference regarding taking care of offspring, as for cleaning offspring and keeping them warm. Taking into account sex and size of offspring, those from control and thyroxine-treated mothers presented no significant difference of weight and weaning. In conclusion, administering low doses of thyroxine increases apoptosis rate, which is characterized by the increased caspase-3 immunoexpression in mammary epithelial cells 5 days after weaning. But does not affect proliferation rate and development of thyroxine-treated rats offspring.