Cilj istraživanja: Cilj istraživanja bio je utvrditi obrazac izražaja metalotioneina (MT I+II) i proteina toplinskog šoka Gp96 na genskoj i proteinskoj razini u procesima proliferacije i diferencijacije stanica tijekom normalnog rasta i embriogeneze, njihov izražaj u limfatickim organima, te pratece promjene fenotipskih i funkcionalnih karakteristika limfatickih stanica, u razlicitim vremenskim intervalima tijekom regeneracije jetre nakon jednotrecinske parcijalne hepatektomije. Buduci da je izražaj metalotioneina usko vezan uz razinu tkivnih metala, nastojale su se ispitati i promjene njihovih koncentracija tijekom regeneracije jetre. Osim toga, analiziran je izražaj metalotioneina i Gp96 na fetomaternalnom spojištu i placentarnim tkivima tijekom normalnog rasta i razvoja u sklopu singenicne trudnoce, kako bi se utvrdio njihov znacaj u procesima placentacije. Materijali i metode: Istraživanja su provedena na C57/Bl6 soju miševa starosti 2 - 3 mjeseca. Promjene proteinskog izražaja utvrdene su imunohistokemijski na parafinskim tkivnim rezovima, odnosno citospin pripravcima, uporabom monoklonskih protutijela i DAKO EnVision + System kita. Indukcija MT-I gena utvrdena je metodom reverzne transkripcije i klasicne lancane reakcije polimerazom, dok su promjene transkripcijske aktivnosti Gp96 gena ustanovljene kvantitativnom lancanom reakcijom polimerazom u realnom vremenu. Apoptoticne stanice detektirane su TUNEL metodom na parafinskim tkivnim rezovima. Koncentracije tkivnih metala odredene su spektrometrijski. Imunofenotipizacija limfatickih stanica izvedena je metodom izravne imunofluorescencije i analizom protocnim citometrom, kojim su detektirane i mrtve stanice u sklopu funkcijskog testa citotoksicnosti. Fetalna i placentarna tkiva analizirana su 16. dana gestacije. Rezultati: Nakon jednotrecinske parcijalne hepatektomije utvrden je brzi porast izražaja stresnih proteina metalotioneina i glikoproteina 96 u regenerirajucoj jetri, slezeni, timusu i koštanoj srži, uz promjene transkripcijske aktivnosti MT-I i Gp96 gena. Istovremeno je zabilježen i porast koncentracija Zn2+, Ca2+, Mg2+ i Fe2+ iona u tkivu regenerirajuce jetre, pracen padom koncentracija ovih metala u slezeni, te padom koncentracije Zn2+ u timusu. Podrucja regenerirajuce jetre u kojih je ustanovljeno prisustvo apoptoticnih hepatocita pokazivala su inverzan odnos sa podrucjima u kojima je bio prisutan snažan izražaj MT I+II proteina. Porast izražaja stresnih proteina MT I+II i Gp96 nakon parcijalne hepatektomije bio je pracen porastom udjela aktiviranih NKT stanica u jetri, T regulacijskih stanica u jetri i timusu, te aktiviranih dendritickih stanica u jetri i slezeni. Nadalje, utvrdeno je da je parcijalnom hepatektomijom potaknut izražaj TLR2 u slezeni i timusu, gdje je ujedno znacajno porastao udio timocita koji podliježu apoptozi. Istodobno, mononuklearne limfaticke stanice jetre i slezene stekle su veci stupanj NKT i NK citotoksicne aktivnosti. Izražaj MT I+II i Gp96 proteina bio je prisutan u mnogim fetalnim tkivima, napose u epitelnima, kao i u podrucju fetomaternalnog spojišta. Zakljucak: Porast izražaja MT I+II i Gp96 proteina u tkivu jetre i limfatickih organa nakon parcijalne hepatektomije, kao i njihovo prisustvo u fetalnim i placentarnim tkivima, ukazuju na ulogu ovih proteina u proliferacijskim zbivanjima tijekom tkivnog rasta, te u indukciji i aktivaciji autoreaktivnih klonova stanica, kao što su NKT i T regulacijski limfociti, koji bi mogli sudjelovati u kontroli reparacijskog procesa i kompenzatornog rasta, ali i u održanju imunološke tolerancije nakon tkivnog oštecenja. Objectives: The aim of this study was to assess the expression pattern of methalothioneins (MT I+II) and heat shock protein Gp96 at gene and protein level during proliferative and differentiation processes in the course of normal growth and embryogenesis, their expression in lymphatic organs as well as the concomitant phenotypical and functional changes of lymphatic cells, at different time points during the liver regeneration induced by one-third partial hepatectomy. Since metallothionein expression is closely related to metal tissue content, during the regenerative process we examined the tissue concentrations of Zn2+, Ca2+, Mg2+ and Fe2+. Additionally, metallothionein and Gp96 expression were analyzed on feto-maternal interface and placental tissues during normal growth and development in context of syngeneic pregnancy, in order to appoint their importance in placentation processes. Materials and methods: The study was performed on mice of strain C57/Bl6, aged 2-3 months. Protein expression was determined by immunohistochemistry on paraffin-embedded tissue sections and citospin preparations using monoclonal antibodies and DAKO EnVision + System kit. In order to examine MT-I gene induction, reverse transcription polymerase chain reaction was done, whereas transcriptional changes of Gp96 gene were assessed by quantitative real-time polymerase chain reaction. Apoptotic cells were detected by TUNEL method. Tissue metal concentrations were investigated spectrometricaly. Phenotypic analyses of mononuclear lymphatic cells were performed by direct immunofluorescent staining and flow cytometry, which was also used to detect death cells during functional cytotoxicity assay. Results: The data revealed that one-third partial hepatectomy leads to high overexpression of stress proteins metallothioneins and Gp96 in regenerating hepatocytes, as well as in spleen, thymus and bone marrow, accompanied by transcriptional changes of MT-I and Gp96 genes. Simultaneously, accumulation of Zn2+, Ca2+, Mg2+ and Fe2+ ions was noticed in the regenerating liver, while there was a concurrent decrease of all these metals in the spleen, and the concentration of Zn2+ in the thymus. The areas containig apoptotic hepatocytes in the regenerating liver inversely correlated with those overexpressing MT I+II proteins. MT I+II and Gp96 upregulation after partial hepatectomy was followed by accumulation of activated NKT cells in the liver and increased proportion of regulatory T cells in the liver and thymus, as well as activated dendritic cells in the liver and spleen. In addition, TLR2 induction after partial hepatectomy was observed in the spleen and thymus, where the increased proportion of apoptotic thymocytes was also found. Simultaneously, intrahepatic and splenic mononuclear lymphatic cells acquired enhanced NKT and NK cytotoxic activity. The data also showed that MT I+II and Gp96 expression is highly upregulated during embryogenesis, particularly on several epithelial tissues, as well as at area of feto-maternal interface. Conclusion: Upregulation of MT I+II and Gp96 proteins in liver and lymphatic organs following partial hepatectomy, and their presence in fetal and placental tissues, points out the role of these proteins in proliferative processes during tissue growth, as well as in the recruitment and activation of autoreactive clones of cells, such are NKT and regulatory T lymphocytes, that might participate in the control of reparatory processes and compensatory growth, and in the maintainance immunological tolerance after tissue injury.