The modulating effect of amino acids on an organotypic culture of lymphoid tissue

The effect of 20 essential and nonessential L-amino acids on the dynamics of development of spleen explants from 1-and 21-day-old rats on an organotypic tissue culture was studied. The hydrophilic amino acids with a higher molecular mass (asparagine, lysine, arginine, and glutamic acid) induced an inhibitory effect on the growth zone of explants of immature tissue from 1-day-old animals and an opposite, stimulating effect on the mature spleen tissue of 21-day-old rats. An immunohistochemical analysis revealed a reciprocal correlation between the expression of the proapoptotic protein p53 and the cell proliferation upon the action of lysine, asparagine, and glutamic acid. The role of polar amino acids in the modulation of cell proliferation and apoptosis in dependence on the period of ontogenesis was determined.     

The modulating action of amino acids upon development in an organotypic culture

The effect of L-amino acids in concentration 0.05 ng/ml was investigated in organotypic tissue culture of spleen, liver and brain cortex at the age of 1 and 21 days. The high molecular and low hydrophobic amino acids: asparagin, lysine, arginine, and glutamine, are active inducing both a less intensive growth zone in explants of all three tissue types in 1-day old rats and more intensive growth zone in spleen, liver explants in 21-day rats as compared to control. Another group of low molecular and high hydrophobic amino acids is active inducing a more intensive growth zone in brain cortex explant in 21-day rats, as compared to control. The data obtained suggest a modulating role of amino acids in the tissues at different stages of maturation.     

The modulating role of essential and non-essential amino acids in organotypic tissue culture in rats of different ages

The effect of amino acids L-lysin, L-asparagin, L-arginin, L-glutamate was investigated in organotypic tissue culture of spleen, liver and brain cortex of rats at different age. The amino acids in concentration 0.05 ng/ml are active inducing a less intensive growth zone, as compared to control, in 1-day and in older rats--an intensive growth zone, as compared to control in 21-day rats. The data obtained suggest a modulating role of amino acids in the tissues at different stages of maturation.     

The effect of the coded amino acids on meso- and ectodermal tissue development in organotypic culture

The effect of L-amino acids was investigated in organotypic tissue culture ofmesodermal tissue (spleen, myocardium) and ectodermal tissue (brain cortex) in mature rats. The low hydrophobic amino acids: asparagine, hystidine, serine, lysine, arginine and glutamine acid, induced the proliferation stimulation. The high hydrophobic amino acids had both the apoptose effect (spleen) and no effect at all (myocardium). The proliferation stimulation occurred in the ectodermal tissue under the effect of the high hydrophobic amino acids (asparagines acid, valine, threonine, methionine, leucine, isoleucine), whereas the low hydrophobic amino acids had no effect on the nervous tissue development. The combination of two amino acids one of which stimulated and another one inhibited the explant growth zone (or was not active in myocardium) lead to an increase of the stimulatory effect in meso- and ectodermal tissue. The amino acid modulated properties can be taken in consideration in synthesis of new regulatory peptides.     

Regulating role of various amino acids in development of apoptosis in organotypic culture of the nervous and lymphoid tissue

The effect of aminoacids L-arginin, L-lysine, L-asparagin was investigated in organotypic tissue culture of brain cortex and spleen of 1-day old rats. The aminoacids in concentrations 0.05 and 0.1 ng/ml are active, inducing a less intensive growth zone as compared to the control, excluding the effect of asparagin on lymphoid tissue. Method of fluorescent staining shows a negative correlation between growth zone size and apoptotic cell number. The nerve and lymphoid tissue express apoptosis in response to aminoacids.     

Effect of amino acids on cell proliferation and protein p53 expression in organotypic culture of lymphoid tissue from neonatal rats

The effect of the larger molecular weight l-amino acids on the development of spleen explants from 1- and 21-day rats in organotypic tissue culture was studied. The amino acids asparagine, lysine, arginine, and glutamic acid inhibited the growth zone of explants of immature tissue from 1-day animals but had an opposite, stimulating, effect on mature spleen tissue of 21-day rats. Immunohistochemical analysis revealed a reciprocal correlation between the expression of the proapoptotic protein, p53, and T-cell proliferation in response to lysine, asparagine, and glutamic acid. Interestingly only arginine reduced the area of p53 expression both in explants of mature and immature spleen tissue. The ability of arginine to reduce p53 expression can be suggested as one of the mechanisms of the tumor growth stimulation.     

The comparative analysis of the effect of oligopeptides and amino acids on the development of rat different tissue culture

The effect the synthetic tetra-, tripeptides and amino acids, composed them, in concentration 10(-12) M was investigated in organotypic tissue culture on the cell proliferation and apoptosis development in six tissue explants (ecto-, meso- and entodermal genesis) in rats at age 3 months old. The tetrapeptide demonstrated the greater tissue-specificity, as compared to the tripeptides and amino acids. Each tetrapeptide stimulated proliferation in only one corresponded tissue type. Less tissue-specificity was observed in the tripeptides, which stimulated proliferation and apoptosis in one (one case)--four tissues. The amino acids stimulated proliferation and apoptosis in three--five tissues. It can be suggested, that tissue-specificity in these biologically active substances is depended on the structure complexity. It is discussed, that the tetrapeptide tissue-specificity is related to the complementar interaction to the DNA site-specific blocks.     

The stimulating effect of prolactin on the neurite growth of sensory neurons in an organotypic culture

Prolactine was found to promote neurite extension in chick embryo dorsal root ganglia in vitro. This hormone was active at the concentration 10-50 ng/ml provided extensive neurite outgrowth in the bioassay, compared to the control. The liquor from patients with prolactinoma was also found to promote neurite extension. This fact may be used for prolactinoma diagnostics.     

The effect of ouabain on sensory neuron neurite growth in organotypic culture

Ouabain, a known inhibitor of Na+, K(+)-ATP, taken in a wide range of concentrations, was investigated in organotypic tissue culture of dorsal root ganglia cells of 10-11 day old chick embryos. Ouabain inhibited neurite growth in a dose-dependent manner. The Hill coefficient was defined as 1, and the Kp value was estimated as 1 x 10(-10) M. At inhibitor concentrations exceeding 1 x 10(-9) M, the growth of neurites was totally inhibited. It is assumed that Na+, K(+)-ATPase may play an important role in regulation of the process of neurite growth in sensory neurones.     

The prion organotypic slice culture assay--POSCA

Methods enabling prion replication ex vivo are important for advancing prion science. However, few such technologies exist and many prion strains are intractable with them. Here, we describe a prion organotypic slice culture assay (POSCA), which allows for prion amplification and titration ex vivo under conditions that closely resemble intracerebral infection. Organotypic slices are incubated with infectious inoculum as free-floating sections, washed and cultured for up to 8 weeks. Slice cultures are a rich source of protein or RNA and allow for stringent comparisons between uninfected and prion-infected samples generated from the same mouse. Thirty-five days after contact with prions, cerebellar slices have amplified PrP(Sc) quantitatively similar to that seen in vivo, but accelerated fivefold. The POSCA detects replication of specific prion strains from disparate sources, including bovines and ovines, with variable efficiency. The culture procedure and prion infection can be performed in 8 h.