Structural Changes in the Nervous Fibers of the Colon Mucosa in Experimental Acute Colitis.

Morphological, morphometric, and ultrastructural analysis of the nerve fibers in the colon mucosa was performed in C57BL/6 mice at various terms of development of acute colitis induced by dextran sodium sulphate. The nerve fibers were labeled with antibodies to pan-neuronal marker ßIII-tubulin. The progression of inflammatory and ulcerative processes in the mucosa on days 3-5 was associated with hyperplasia and hypertrophy of nerve fibers that peaked on day 7 after colitis induction. Ultrastructural analysis at all terms of colitis development showed moderate degeneration of axons. Thus, hypertrophy and hyperplasia of the nervous fibers in colon mucosa in experimental acute colitis correlated with aggravation of the ulcerative process in the mucosa. These changes are determined by alteration of histoarchitectonics and regenerative processes in the mucosa.

Sex-Related Differences in the Morphology and Subpopulation Composition of Colon Lymphocytes in Experimental Acute Colitis.

Morphological manifestations of acute colitis and subpopulation composition of colon lymphocytes were studied in male and female C57Bl/6 mice with acute dextran-induced colitis. We evaluated the severity of colitis symptoms, morphological changes in the colon, and prevalence of epithelialized and non-epithelialized ulcers. The subpopulation composition of lymphocytes (CD3-CD19+ B cells, CD3+CD4+ T helpers, CD3+CD8+ cytotoxic T cells, and CD4+CD25+FOXP3+ regulatory T cells) was assessed by flow cytofluorometry in suspension of colon cells prepared by enzymatic disintegration. In males, clinical manifestations of acute colitis and morphological changes were more severe and the prevalence of non-epithelialized ulcers was higher than in females. In females, the content of T, B, and regulatory T cells in the colon wall was higher, while the content of cytotoxic T cells was lower than in males. In females with acute colitis, the absolute lymphocyte count and the content of B cells and regulatory T cells decreased, while the percentage of cytotoxic T cells increased in comparison with intact animals. In males with acute colitis, the levels of regulatory T and B cells increased in comparison with the corresponding parameter in intact animals. Morphological changes and changes in the lymphocyte subpopulations, detected in males and females with acute colitis, were determined by different levels of sex steroid hormones.

Morphological Changes in Mesenteric Lymph Nodes and Lymphocyte Subpopulation Composition in Experimental Ulcerative Colitis.

Morphological changes in the mesenteric lymph nodes of male C57Bl/6 mice and subpopulation composition of lymphocytes in these nodes were studied in experimental acute and chronic ulcerative colitis induced by sodium dextran sulfate. Acute and chronic ulcerative colitis was associated with the development of reactive changes in the mesenteric lymph nodes. These changes were of mixed type and were characterized by follicular hyperplasia and sinus reaction. The content of CD19(+) B cells in the mesenteric lymph nodes decreased in acute ulcerative colitis, while the content of CD3(+)CD8(+) cytotoxic T cells increased, which presumably reflected activation of Th1 reactions. The increase in the count of CD4(+)CD25(+)FOXP3(+) regulatory T cells and CD3(+)CD8(+) cytotoxic T cells was due to intensive migration of lymphocytes from the thymus and the colonic compartment of the local immune system. Chronic ulcerative colitis was associated with higher levels of CD19(+) B cells and CD3(+)CD4(+) T helper cells in the mesenteric lymph nodes, which was characteristic of adoptive immunity reactions and chronization of the inflammatory process.

[Colonic morphological changes in experimental chronic colitis induced by dextran sulfate sodium].

OBJECTIVE: To characterize morphological changes in the colonic wall in experimental chronic colitis induced by dextran sulfate sodium (DSS). MATERIAL AND METHODS: Experiments were carried out on sexually mature male C57B1/6 mice. Drinking water in the animal dishes was replaced by 2% DSS solution for 6 days and the animals were taken away from the experiment on day 21 after initiation of DSS consumption. Hematoxylin- and eosin-stained colonic histological specimens were prepared by Masson's trichrome and Nissl methods. RESULTS: Histologically, the colonic wall displayed epithelialized ulcers; mucosal remodeling; reductions in the count of goblet cells, crypts and their depth; mucosal inflammatory infiltration with lymphocytes, plasmocytes, and histiocytes; lymphoid tissue hyperplasia; diffuse and focal sclerosis of all colonic membranes; neuronal destructive changes in the myenteric and submucosal nerve plexuses. CONCLUSION: The experimental model of DSS-induced chronic colitis corresponds to human colitis in morphological characteristics to a certain degree and may be used to study of the pathogenesis of this disease and to preclinically evaluate of the efficacy of medications.

[A morphological study of regeneration of the goldfish elasmoid scales].

Studies were carried out on the model of regeneration of mechanically removed elasmoid scales. Regenerating scales were morphologically analyzed using light and electron microscopy. It was found that the cells responsible for regeneration of the elasmoid scale plates could be classified as osteogenic elements. Little differentiated preosteoblasts were detected in the connective tissue of dermis on day 3 of regeneration, while partially calcified plates underlaid osteoblasts on day 7. The scale cover was fully restored on day 14 and it took two days for each bone plate to be formed. Osteocytes, fully differentiated osteogenic elements, were found in the deepest regions of newly formed scales.

Morphochemical features of plastic rearrangements of hippocampal neurons after rhythmic stimulation of the limbs in elderly rabbits.

The process of aging is accompanied by significant derangements to brain function, which are expressed particularly as the well-known phenomenon of memory disturbance [4,5]. Since memory functions are based on plastic rearrangements, in which the key role is played by metabolic processes, we elected to study the interactions between nerve cell activity and the state of protein biosynthesis during the formation of temporal associations in animals of different ages [3]. An interferometric method was considered appropriate in this regard as a method for estimating the dry weight of the cytoplasm and nucleus in neurons; this serves as a measure of their protein contents [1,2]. The aim of the present work was to identify the relationship between the process of impressing the assimilation trace of a rhythm during the acquisition of an analog of a conditioned reflex to time in hippocampal neurons and their morphochemical parameters in elderly rabbits.

[The morphochemical characteristics and plastic restructurings of the hippocampal neurons after rhythmic stimulation of an extremity in old rabbits]. / Morfokhimicheskie osobennosti i plasticheskie perestroiki gippokampal'nykh neironov posle ritmicheskoi stimuliatsii konechnosti u starykh krolikov.

The rhythmic activity of CA1 hippocampal neurons was studied after the rhythmic (1-2 Hz) electrocutaneous forelimb stimulation (10-20 min) of 6-84-months-old rabbits. The spectral analysis of neuronal activity revealed the age-dependent decrease in ability to reproduce the rhythm of stimulation. The cytochemical data showed that the protein synthesis in the neurons under study also declined with age.

Morphochemical changes in brain structures in the course of chronic haloperidol treatment and the correction of these changes with tuftsin.

The systemic injection of haloperidol (4 wk, 0.5 mg/kg/d) caused the increase of protein concentration and content, and the activity level of aminopeptidase in the cytoplasm of the neurons of associated type (layer III). The nucleus of these cells decreased both in sizes and in the content of proteins. In the neurons of efferent-projectory type (layer V), the decrease of studied peculiarities as compared with control level was observed. Tuftsin (300 micrograms/kg/d) injection after chronic haloperidol treatment causes the restoring action on changed parameters in sensomotor cortex. In caudate nucleus, tuftsin influence caused further reduction of neuron's cytoplasmic area and significant reduction in protein content. The received results testify to the morphobiochemical heterogenity of investigated brain structures, which is displayed both in the case of haloperidol treatment and in the case of its correction by neuropeptide tuftsin. Chronic haloperidol administration to animals can develop a model of certain symptoms and syndromes of parkinsonism. Its most pronounced manifestation is an imbalance in the neuromediator systems, especially the dopaminergic one (Mettler and Crandall, 1959; Colls, 1984; Funk et al., 1986). The research was performed in conjunction with the physiologists, whose experiments have shown that after chronic haloperidol administration, changes in animal behavior are developed that are typical for bradikinesia, and the motor regimen of integration is disturbed (Popova and Kachalova, 1991; Dovedova and Povova, 1993). Regulatory drugs, especially the tetrapeptide tuftsin, seem to correct such disturbances.

[The morphochemical characteristics of the reaction of the motor structures of the brain to hyper- and hypofunction of the dopaminergic system]. / Morfokhimicheskie osobennosti reaktsii dvigatel'nykh struktur mozga na giper- i gipofunktsiiu dofaminergicheskoi sistemy.

The investigation of protein (aminopeptidase activity, structured proteins) and of mediator metabolism (monoaminoxidase A and B activities, acetylcholine esterase, Ca(2+)-uptake) was carried out in rat brain motor structures. The study was performed during chronic L-DOPA and haloperidol administration that is under the conditions of hyper- and hypofunction of dopaminergic system. Some peculiarities and differences of sensomotor cortex and nucleus caudatus' reactions to the dysfunction of DA system were revealed at the cellular and subcellular levels. The results show the existence of high morpho-biochemical plasticity of brain structures mentioned above.

[The functional and morphochemical characteristics of the hippocampal neurons during the formation of trace processes in old rabbits]. / Funktsional'nye i morfokhimicheskie osobennosti neironov gippokampa pri formirovanii sledovykh protsessov u krolikov starogo vozrasta.

Trace rhythmic activity of dorsal hippocampal neurons were studied after the long-lasting (10-20 min) rhythmic (0.5-2 Hz) electrocutaneous stimulation of the forelimb in alert young (5-7 months), middle-aged (54-65 months), and very old (66-84 months) rabbits. During aging the number of spontaneously active neurons was shown to be significantly decreased, the proportion of slowly firing neurons to be increased, the interspike intervals and intervals between spike groups to lengthen, and the number of spikes per a group to be reduced. Spectral analysis of neuronal firing rate revealed that ability to reproduce the rhythm of the previous stimulation declined with age. No appropriate rhythms were found in hippocampal neurons of the old animals. Morphological and cytochemical analysis of the hippocampal neurons revealed changes in nuclear-cytoplasmic relations and also a fall of protein synthesis in the neurons of the old animals. The observed deteriorations may explain the impairment of trace rhythmic activity in hippocampal cells with age.