Morfološka i stereološka ispitivanja jedara bazolateralnog dela amigdaloidnog kompleksa pacova neonatalno tretiranih estrogenom

Abstract

U cilju boljeg poznavanja topografije i morfologije bazolateralnog dela amigdaloidnog kompelksa (AK) pacova, kao i u cilju analiziranja razlika u njegovoj osetljivosti na egzogeno neonatalno aplikovan estrogen, stereološkim i histološkim metodoma ispitivana su dva jedra: bazolateralno (NBL) i posteriorno lateralno jedro (NLp). Ispitivanja su sprovedena na mužjacima i ženkama pacova koji su tretirani jednokratno sa l mg estradiol- dipropionata 3. dana po koćenju, a žrtvovani, zajedno sa svojim kontrolama, u odgovarajućim periodima života: kasnom neonatalnom (16. dana), juvenilnom (38. dana) i adultnom periodu (86. dana). Kod kontrolnih životinja oba pola, analizom morfologije ova dva jedra, u svim ispitivanim starostima, jasno se uočavaju dobro diferentovani anteriorni i posteriorni subregioni, determinisani na osnovu rostro-kaudalnog pružanja, na osnovu oblika i veličine tela neurona, kao i gustine populacije neurona koji im pripadaju. Neuroni bazolateralne amigdale impregnirani Goldži metodom, pokazuju sličnost po obliku i veličini tela neurona i dendritske morfologije. Najčešće impregnirani tip u oba ispitivana jedra bazolateralnog dela AK su krupni bipolarni i multipolarni piramidalni i kruškoliki neuroni sa 1 do 2 dobro razvijena apikalna dendrita i tankim aksonom u predelu osnove tela neurona. Stereološka analiza ispitivanih parametara (volumenske gustine) jedra neurona, ukazala je na postojanje strukturnog polnog dimorfizma u svim ispitivanim starosnim grupama kod bazolateralnog i kod posteriornog lateralnog jedra, dok stereološka analiza numeričke gustine odnosno broja neurona u ispitivanoj jedinici prostora kod bazolateralnog i posteriornog lateralnog nukleusa, pokazala je, da nije bio statistički značajne izmene u odnosu na pol životinja, u svim ispitivanim periodima života. Sa starošću životinja, kod ženki pacova, za razliku od mužjaka, za oba ispitivana nukleusa, vrednosti volumenske gustine jedara neurona bile su najviše u ispitivanom neonatalnom periodu razvića. Kod neonatalno tretiranih mužjaka i ženki pacova žrtvovanih 16. 38. i 86. dana života u okviru ispitivanih nukleusa i dalje se na osnovu rostrokaudalnog pružanja, oblika i veličine tela neurona, kao i gustine populacije neurona, koji im pripadaju, uočavaju njihovi dobro diferentovani anteriorni i posteriorni subregioni. Krupni piramidalni i kruškoliki neuroni bazolateralne amigdale, takođe su najdominantniji impregnirani tip neurona u oba ispitivana jedra, a vrednosti totalne aree njihove some pokazale su značajna statistička odstupanja u vezi sa ispitivanim periodom, kao i u odnosu na pol životinje. U oba ispitivana nukleusa, stereološki rezultati pokazali su značajni dimorfizam promena; kod bazolateralnog jedra, sem vrednosti volumenske gustine međućelijskog prostora, kod 16. i 38. dana žrtvovanih životinja, i volumenske gustine citoplazme, kod 38. dana žrtvovanih životinja, svi ostali stereološki parametri, bili su statistički značajno različiti (p<0.05) među polovima; kod posteriornog lateralnog jedra takođe, sem volumenske gustine citoplazme 16. i 38. dana žrtvovanih životinja i volumenske gustine međućelijskog prostora kod 38. dana žrtvovanih, sve ostale vrednosti ispitivanih stereoloških parametara, takođe su bile signifikantno različite (p<0.05) u odnosu na pol životinja. Sa starošću životinja, kod oba pola, za oba ispitivana nukleusa, vrednosti volumenske gustine jedara neurona bile su najviše u ispitivanom neonatalnom periodu razvića sa tendencijom opadanja u juvenilnom i adultnom periodu života. Na osnovu dobijenih rezultata može se zaključiti da je estrogen iako dat jednokratno u neonatalnom periodu izazvao promene u odnosu na pol životinje i ispitivani period života.

In order to get a deeper knowledge of topography and morphology of the basolateral part of the rat amygdaloid complex (AC), as well as to analyse diferences in its sensitivity to exogenously neonatally applied estrogen, two nuclei, basolateral (NBL) and posterior lateral (NLp), were studied by stereological and histological methods. The study was performed on male and female rats treated with a single dose of 1 mg of estradiol dipropionate on the third day after birth, and sacrificed, together with appropriate controls, in different periods of life, late neonatal (16th day), juvenile (38th day) and adult period (86th day). In control animals of both sexes, by analysis of morphology of these two nuclei, in all investigated periods of life well differentiated anterior and posterior subregions determined on the basis of rostrocaudal extension, shape and size of neuron body, as well as the density of appropriate neuron populations, are clearly observed. Neurons of the basolateral amygdala, impregnated by Golgi method, show similarities in shape and size of the neuron body and dendrite morphology.The most frequently impregnated type in both examined nuclei of the basolateral part of AC are large bipolar and multipolar pyramidal and pear-like neurons with one or two well developped apical dendrites and a thin axon in the region of the basis of the neuron body. Stereological analysis of the investigated parameters (volume density) of the neuron nucleus indicated the existence of structural sexual dimorphism of basolateral and posterior lateral nuclei in all investigated age groups, while stereological analysis of numerical density, i.e. number of neurons in unit of investigated volume, with basolateral and posterior lateral nuclei, showed that there was no statistically significant change with respect of sex of the animals, in any period of life. With respect to the age of the animals, in female rats, in contrast to male rats, for both investigated nuclei, values of volume density of neuron nuclei were highest in the investigated neonatal period of development. With neonatally treated male and female rats sacrificed on 16th, 38th and 86th day, within the examined nuclei, based on rostrocaudal extension, shape and size of the neuron body, as well as the population density of the corresponding neurons, still can be observed their well differentiated anterior and posterior subregions. Large pyramidal and pear-like neurons of the basolateral amygdala are also the dominant impregnated neuron type in both investigated nuclei and the values of total area of their soma showed a significant statistical deviation concerning the investigated period and the sex of the animals. In both investigated nuclei stereological results showed a significant dimorphism of changes; with basolateral nuclei except the value of the volume density of the intercellular space with the animals sacrificed on the 16th and 38th day and the volume density of the cytoplasm with the animals sacrificed on the 38th day all the other stereological parameters were statistically significantly different (p< 0.05) between sexes; with posterior lateral nucleus except the volume density of the cytoplasm of the animals sacrificed on 16th and 38th day, and the volume density of the intercellular space with the animals sacrificed on the 38th day all the other values of the stereological parameters were also significantly different (p< 0.05) with respect to the sex of the animals. Regarding the age of the animals of both sexes, for both examined nuclei, the values of the volume density of neuron nuclei were highest in the investigated neonatal period of development, with the decreasing trend in juvenal and adult periods of life. Based on the obtained results it can be concluded that the estrogen, although applied in one dose in the neonatal period, caused changes with respect to the sex of the animals, and the investigated period of life.