Search

Utilization of rabbits as experimental animals is oriented to specific populations because of user goals. Human diseases, organ transplantations, physiological experiments, feeding trials or genetic experiments are most frequent examples for exploration of rabbits. These utilizations are associated with homogenous genetic background, which can be reached by inbredisation process. Depending on the type of observed and applied traits, homozygotation can be an effective way to create appropriate populations with unique characteristics. We used 3 panmictic rabbit populations (New Zealand White - NZW, Californian - C and Nitra rabbit - Ni) for directed selection during 5 generations. In the course of inbredisation, the animals were mated inter se (full siblings with each other). Initial (founder) animals were selected from a wider population and they formed the original parental groups with 20 does and 5 males of each breed. At average, the same number of selected animals was mated for next generation. Selection criteria were following: for NZW it were - increase of live weight, for C - high level of untroubled behaviour, and for Ni - long ear shell with clear blood vessel. NZW animals were selected on the basis of regular weekly measuring of live weight. Californian rabbits were tested in open field equipment for peaceful habitus as a number of movements per time unit. Animals in Nitra breed population were selected basing on the ear length and good visualisation of central ear blood vessel. In addition to the selected traits, in all three populations the standard breed characteristics were maintained. After the 5 year selection process the results are following: in the 5th generation of NZW rabbit population an average initial live weight was increased daily from 25.4 ± 6.2 g to 30.2 ± 3.2 g. It represents difference in 411.6 g at slaughter age in favour of the inbred population. Panmictic Californian rabbits had 25.6 ± 7.5 movements in contrast to 14.5 ± 5.7 units for animals in inbred population. The length of ear in the initial Nitra rabbits was 11.5 ± 1.6 cm in comparison to the inbred population (13.5 ± 1.8 cm). According to these results, inbredisation is an effective process for creating relevant populations. [ABSTRACT FROM AUTHOR]

Human adipose tissue-derived mesenchymal stem cells (AT-MSCs) have been studied several years for their immunomodulatory effect through the paracrine mechanism and cytokine secretion. In combination with endothelial progenitor cells (EPCs), MSCs have great therapeutical potential for the repair of endothelium and wound healing. However, little is known about the cytokine profile of rabbit AT-MSCs or even EPCs. The aim of this study was to analyze the secretomes of these rabbit stem/progenitor cells. A large-scale human cytokine array (up to 80 cytokines) was used to identify and compare cytokines secreted into conditioned media of human and rabbit AT-MSCs as well as HUVECs and rabbit EPCs. Few cytokines were highly expressed by human AT-MSCs (TIMP-2, TIMP-1), HUVECs (MCP-1, TIMP-2, GRO, Angiogenin, IL-8, TIMP-1), or by rabbit EPCs (TIMP-2). Several cytokines have moderate expression by human (MCP-1, GRO, Angiogenin, TGF-β 2, IL-8, LIF, IL-6, Osteopontin, Osteoprotegerin) and rabbit AT-MSCs (TIMP-2, TGF-β 2, LIF, Osteopontin, IL-8, IL-5, IL-3) or by HUVECs (IL-6, MIF, TGF-β 2, GCP-2, IGFBP-2, Osteoprotegerin, EGF, LIF, PDGF-BB, MCP-3, Osteopontin, Leptin, IL-5, ENA-78, TNF-β) and rabbit EPCs (TGF-β 2, Osteopontin, GRO, LIF, IL-8, IL-5, IL-3). In conclusion, the proposed method seems to be useful for the secretome analysis of rabbit stem/progenitor cells.

Bone tissue microstructure of femur was investigated in transgenic New Zealand White rabbits with human factor VIII gene. Altogether 42 bones (24 from transgenic rabbits and 18 from non-transgenic ones) were analysed. Specimens were prepared using standard histological equipment, producing thin sections of approximately 80-100 microm. For histomorphometrical analysis areas, perimeters, minimum and maximum diameters of osteons' vascular canals and of osteons were measured. We found out that the basic structural pattern of femoral bone tissue was primary vascular longitudinal in both groups of rabbits. However, a new type of the bone tissue--fibrolamellar--was identified only in the transgenic rabbits. The measured variables of the osteons' vascular canals were higher in transgenic individuals in comparison with the nontransgenic ones (except for maximal diameter) and the differences were statistically significant (P < 0.05; P < 0.01). We suppose that the observed differences could be associated with transgenesis. In an effort to explain these differences we compared the cytogenetic profile of bone marrow cells between transgenic and non-transgenic rabbits. A significantly higher rate of aneuploidy was observed in c-metaphase spreads of transgenic individuals as compared to non-transgenic ones (P < 0.001). Despite the fact that no hFVIII mRNA expression was found in the femur of transgenic rabbits, we discussed an association of transgene integration into the genome and microstructural changes in the bone. In any case, the results indicate that transgenesis can also produce changes in other tissues than in the target ones.

The aim of this study was to determine whether there are differences in the karyotypes between transgenic and non-transgenic or control rabbits. New Zealand White transgenic rabbits (F1 generation) were obtained after breeding of transgenic founder rabbits that were derived from single--SM--or double microinjection--DM--with a WAP-hFVIII transgene. C-metaphase plates were obtained from short-time culture of peripheral blood lymphocytes synchronized by the addition of colcemide. A significantly higher rate of aneuploidy was observed in c-metaphase spreads of transgenic (56-66%) rabbits, as compared to non-transgenic ones (28-38%) (P < 0.05; P < 0.01). The patterns of chromosome banding were identical in both groups of rabbits. No structural aberrations were revealed in either group. These findings demonstrate that transgenic rabbits have a higher frequency of numerical chromosomal aberrations in their peripheral blood lymphocytes than normal rabbits, but without apparent deleterious effects on health or reproduction.

For the first time the visualization of cock sperm chromosomes using zona-free hamster eggs was described. Different variants of egg treatment were tested: varying the duration of incubation of eggs with spermatozoa from 5-6 to 20 h and the cytostatic treatment (colchicine) from 35 min to 9 h, varying the concentration of colchicine from 0.4-400 micrograms/ml and the hypotonic treatment with 0.1% and/or 1.0% sodium citrate or with distilled water from 2-5 to 12 min. In all variants sperm penetration was found, with changes in the head of sperm and the formation of pronucleus but there was no breakdown of the pronuclear envelopes. Only experiments, in which eggs were incubated without colchicine, were successful.

The effect of the system of mating and the way of killing on the aldolase activity in the tissue of rabbits was the task of this research work. The research work was realized in 201 New Zealand white rabbits aged 140 days, mated outbred and inbred. Two methods of killing were used: classical method, which was based on the stroke and break the spinal cord; and killing with the help of treating with an i/m infection of 10 per cent of magnesium sulphate (2 ml per 1 kg of weight). In blood serum and in liver homogenates, kidneys and dorsal muscle the aldolase activity was determined by the method of Bruns. No significant differences in the aldolase activity between outbred and inbred rabbits were found. Statistically high significant differences, conditioned by killing method, were stated in activity of enzyme.