Phenotypic differences between mdx black mice and mdx albino mice. Comparison of cytokine levels in the blood.

In mdx mice, mutation in the muscle protein dystrophin gene results in the development of chronic degeneration of the muscle tissue. We performed a comparative analysis of blood cytokine levels in mdx mice, classical black mice and mice with additional genetic defect responsible for the manifestations of oculocutaneous albinism. In mdx albino mice, the total pool of cytokines (IL-10, IL-6, IL-5, IL-2, IL-1α, IL-4, IL-17, granulocyte-macrophage growth factor, TNF-α, and IFN-γ) was increased. This increase was not associated with selective release of one of the above cytokines into the blood. The fraction of pro-inflammatory cytokines (IL-6, IL-1α, TNF-α) was increased in the total pool and the percentage of antiinflammatory cytokines (IL-4) was reduced. Changes in cytokine pool probably reflect the differences in the severity of the pathological process in the muscle tissue of both genetic variations of mdx mice.

Cytokine profile of the blood in mice with normal and abnormal heart rhythm.

Differences in the pools of 10 cytokine were found in blood samples from the caudal vein of mice with normal and abnormal heart rhythm. Both groups were albino mice bred by us and differing from mdx albino mice by the absence of mutation in muscular dystrophin gene. Mice with normal heart rhythm had low IL-17 content and elevated concentrations of proinflammatory cytokines IL-6 and IL-1α in comparison with the normal (according to published data). In mice with bradyarrhythmias, increased blood levels of IL-10, IL-6, IL-5, IL-2, IL-1α, IL-17, IL-4, TNF-α, and granulocyte-macrophage colony-stimulating factor were detected. The relative content of IL-4 and IL-17 in the total cytokine pool increased. The lifespan of mice with bradyarrhythmias and cytokine hyperexpression was shorter by 2-3 months in comparison with mice without heart rhythm disturbances and moderate changes in the cytokine pool.

[Pathological changes in heart activity of mdx mice and future prospects of mdx model in cardioimmunulogy].

Dystrophin is a protein linking the cytoskeleton to a complex of transmembrane proteins that interact with the extracellular matrix. The fragility of the cardiomyocyte cell membrane resulting from the lack of dystrophin is thought to cause an excessive susceptibility to mechanical stress. Based on surface ECC we demonstrate the differences of cardiac phenotype in young (2- to 3-mo-old) and aged (over 1,5 years) dystrophin-deficient mdx mouse and normal mouse with the same genetic background. It was shown that main alterations in the mdx electrocardiogram concern primarily ventricular conduction velocity (QRS complex duration) and time of ventricular repolarization (QT interval) duration).The issue under discussion is whether dystrophin deficient mdx model can be used in research studies in cardioimmunology.

A new genetic variant of mdx mice: study of the phenotype.

Genetic selection in a colony of mdx mice (suffering from X-chromosome-linked muscular dystrophy) resulted in generation of their new genetic variant. In this new variant, the genetic, biochemical, and histological markers of muscular dystrophy are combined with signs of oculocutaneous albinism (skin and fur depigmentation), transillumination of the iris, sharply reduced pigmentation of the retinal epithelium, and increase of the eyeball refraction). Two sensorimotor tests (negative geotaxis and wire back down hanging) detected other phenotypical characteristics of albino mdx mice carrying, in addition to the mutation in the dystrophin gene exon 23 (intrinsic of the "classical" black mdx mice), an extra mutation responsible for pigmentation disorders. Slow geotaxis, despite longer wire back down hanging capacity, was regarded as aggravation of the neurological dysfunction in albino mdx mice in comparison with black mdx mice.

[Regenerative activity of muscle tissue and thymus status in young and old mdx mice with muscle injury and wound xenoplasty].

Responses of the skeletal muscle tissue and thymus to muscle injury (complete transection) and wound xenoplasty with the minced muscle tissue of newborn rats (tissue therapy) were studied in mdx mice aged 12-16 and 40-48 weeks. The muscle tissue of mdx mice has genetic defects causing chronic dystrophic processes in it. The muscle tissue of young mdx mice proved to retain a relatively high capacity for regeneration. Under conditions of tissue therapy of the wound, the formation of muscle fibers from muscle cells of the graft and active regeneration of muscle fibers in the recipient mice were observed, and no structural defects were detected in the thymus. The capacity of posttraumatic regeneration in old mdx mice was lower. The xenogenic graft was undergoing resorption, thereby suppressing regeneration of muscle fibers and causing further tissue destruction in the injured muscle. The thymus parenchyma was subject to degenerative changes such as the formation of gaps, hemorrhagic foci, and increased numbers of macrophages and mast cells.

Restoration of gastrocnemius muscle in MDX mice of different age after injury and implantation of xenogenic muscle tissue.

The intensity of regeneration of crossed gastrocnemius muscle was evaluated in two groups of mdx mice of different age 2 weeks after implantation of crushed muscle tissue from newborn rats into the wound defect area. The effect of xenoplasty manifested in increased weight of the damaged muscle. The effect was observed in mice aging 12-16 weeks but not in those aged 40-48-weeks. Structural changes in the skeletal muscle tissue intrinsic of mdx mice and augmenting with age were detected in intact mice before the experiment. Activity of muscle fiber regeneration in intact and injured muscle of 40-48-week-old mice was significantly lower than in 12-16-week-old ones. Myoblasts of the xenogenic transplant retained viability in recipient muscles for at least 2 weeks. posttraumatic regeneration was stimulated in only 12-16-week animals. Xenoplasty was ineffective in older animals and even somewhat enhanced the destructive processes in the muscle. It seems that age-specific regeneration activity of the recipient skeletal muscle tissue should be taken into consideration in the development of effective strategy of cell therapy for progressive muscular dystrophy.

Cardiotropic effect of extracardiac transplantation of embryonic human myoblasts to mice with bradycardia: various effects of cell material.

Animals with bradycardia were detected in reproductive colony of mdx mice. Low pulse rate was associated with poor survival and predisposition to sudden death, but did not directly depend on the presence of dystrophin mutant gene or animal age. Heart rate increased in old mice with bradycardia after extracardial, intramuscular, and intravenous injection of human embryonic myoblasts. Stable normalization of the pulse was observed 2 weeks after transplantation, but early peak of heart rate was observed as early as 24 h after cell transplantation. Cell suspensions, which could contain stem cells (blood mononuclears and CD34+ lymphocytes), also corrected heart rhythm. Unlike the effect of myoblasts, cardiotropic effect of mononuclears was preceded by a period of tachycardia, while the effect of CD34+ lymphocytes was very unstable. The cardiotropic effect of myoblasts was combined with life span prolongation and certain rejuvenation in some animals. Erythrocytes and supernatant obtained during blood cell fractionation did not modify the heart rhythm in mice with bradycardia. After injection of myoblasts to mice with rare and normal pulses serum creatine kinase activity decreased with different rates. These data attest to a variety of biological effects of stem cells and/or their derivatives and to ambiguous mechanisms of these effects.

Hereditary muscular dystrophy in MDX mice as a homologous model for introduction of cell technologies in the treatment of progressive muscular dystrophies in humans.

Life-time monitoring of the main clinical and laboratory manifestations of hereditary muscular dystrophy in mdx mice confirmed the presence of mutation in exon 23 of dystrophin gene and the absence of this protein in skeletal muscles of mutant animals. Muscular dystrophy in mice was similar to human progressive muscle disorder, which allows the use of this model for the development of cell technologies for the treatment of hereditary muscular diseases in humans.

Xenotransplantation of embryonic precursors of human myogenesis for the correction of dystrophinopathy in mice with hereditary muscular dystrophy.

Human embryonic myogenic precursors were transplanted into muscles of mdx mice with hereditary dystrophin-deficient muscular dystrophy. Transplantation induced the synthesis of human dystrophin. The number of dystrophin-positive fibers progressively decreased, however, some of them were preserved even 5 months after transplantation. Our results indicate that xenogeneic transplantation of embryonic myogenic precursors compensates the genetic defect in dystrophin-deficient mice.

[The effect of beta-carotene on the development of adjuvant arthritis and interleukin-1 production in rats]. / Vliianie beta-karotina na razvitie ad''iuvantnogo artrita i produktsiiu interleikina-1 u krys.

The production of interleukin 1 (IL1) by peritoneal and splenic macrophages from rats with adjuvant-induced arthritis on day 17 postadjuvant treatment was not altered compared with normal. Treatment of arthritic rats with beta-carotene reduced hind paw swelling and significantly increased ability of macrophages to secrete IL1 as well as stimulated spontaneous proliferation of splenic lymphocytes. No direct relationship between the release of IL1 from peritoneal and splenic macrophages and increase of hind paw swelling was revealed.

[Effect of tissue-specific proliferation inhibitors on the level of mitotic activity and cell adhesion in disordered innervation]. / Vliianie tkanespetsificheskikh ingibitorov proliferatsii na uroven' mitoticheskoi aktivnosti i adgeziiu kletok v usloviiakh narushennoi innervatsii.

In the work there was studied the influence of hepatic chalones on the level of mitotic activity and on the degree of adhesion of hepatocytes after the violation of parasympathetic and sympathetic innervation under the physiological conditions of liver function and in regenerating organ. Some definite regularities were revealed in the change of the power of linkage among the cells of liver parenchyma after the disturbance of its innervation and chalones affected. Significant differences in the effect of the influence of tissue inhibitors of proliferation on the process of regeneration in liver, which has intact or disturbed innervation were discovered. Particularly one can underline the effect of the loss of hepatocytes sensitivity to chalones in vagotomized liver.