O presente estudo analizou nove gânglios cervicais craniais esquerdos (GCC) de Cutias (Dasyprocta aguti) machos oriundos do criatório da Universidade Federal Rural do Semi Árido Nordestino de Mossoró- RN. Nestes animais foi estimado o número total dos neurônios (mono e binucleados), bem como seus volumes, volume do gânglio, a densidade neuronal e densidade de volume neuronal durante o desenvolvimento pós-natal (maturação): animais neonatos, jovens e adultos. Os GCCs foram fixados com solução de formoldeído (4%) em PBS, embebidos em solução de ágar e seccionados sistemática, uniforme e aleatoriamente para a aplicação dos métodos estereológicos entre os quais disector e rotator ópticos. para a estimativa da densidade e do volume neuronal, respectivamente. Houve diferença significativa entre os grupos etários para os parâmetros: volume ganglionar, número total de neurônios binucleados, volume neuronal médio de neuronios mono e binucleados e densidade de volume neuronal. A conclusão é de que a idade influencia quantitativamente a dinamica neuronal do GCC de cutias e futuramente estes dados servirão como base para a investigação da ocorrência de divisão celular durante o período pós-natal em roedores. / The present study was pursued in nine left cranial cervical ganglia (CCG) of male cutias (Dasyprocta aguti) obtained from the animal house of the Universidade Federal Rural do Semi-Árido Nordestina em Mossoró- RN. The number of CCG neurons as well as their volume, ganglion volume, numerical density and neuronal volume density were estimated during the post-natal development (maturation), in neonates, young and adult animals, by using 3-D design-based stereological methods, e.g., optical disector and optical rotator. Briefly, CCGs were fixed with a 4% formaldehyde solution in PBS, embedded in a 10% agar solution and exhaustively vibrosectioned (SURS) in order to accordingly perform the relevant stereological estimations. There were significant difference between age groups for the follow parameters: ganglion volume, total number of binucleated neurons, mean neuronal volume of mono and binucleated neurons and volume density of neurons. The conclusion is of that the age quantitative influences the dinamic of neuronal cells of the GCC of agoutis. In the future these data will serve as basis for the inquiry of the occurrence of cellular division during the post-natal period in rodents.

Des changements dans le statut thyroïdien altèrent les fonctions testiculaires, impliquant, entre autre, le récepteur à la T3, TRα1. Lorsqu’un récepteur dominant-négatif de TRα1 (TRα AMI) est spécifiquement introduit dans les cellules de Sertoli (lignée TRα AMI-SC), on observe une augmentation significative de l’index de prolifération des cellules de Sertoli à 3 jpp, induisant une augmentation de la densité de ces cellules et du poids testiculaire chez l’adulte. Ce phénotype est corrélé à une modification de l’expression de gènes clés du cycle cellulaire dont Cdk4, JunD et c-myc. Lorsque le récepteur TRα AMI est introduit également dans les cellules de Leydig (lignée TRα AMI-Aro), la sécrétion de testostérone est augmentée. Enfin, nous montrons l’implication de l’isoforme mitochondriale p43 du récepteur TRα1, dans ce contrôle T3- dépendant et autonome de la prolifération des cellules de Sertoli suggérant l’existence d’un crosstalk entre génome nucléaire et mitochondrial dans cette régulation par la T3. / Changes in the thyroid status altered testicular functions, involving thyroid hormone receptors, among them, TRα1 is implied The expression of a TRα1 dominant-negative receptor (TRα AMI) specifically in Sertoli cells (TRα AMI-SC mice) leads to a significant increase in Sertoli cell proliferation at 3 dpp, inducing an increase in Sertoli cell density, testis weight and testicular spermatic reserve at adulthood. This phenotype is correlated with changes in cell cycle gene expression like Cdk4, JunD and c-myc. When TRα AMI is also expressed in Leydig cells (TRα AMI-Aro mice), it induces an increase in testosterone levels. Finally, we demonstrate that the mitochondrial p43 receptor is involved in this T3-dependant control of Sertoli cell proliferation, suggesting the existence of a crosstalk between nuclear and mitochondrial genomes.

O presente estudo analizou nove gânglios cervicais craniais esquerdos (GCC) de Cutias (Dasyprocta aguti) machos oriundos do criatório da Universidade Federal Rural do Semi Árido Nordestino de Mossoró- RN. Nestes animais foi estimado o número total dos neurônios (mono e binucleados), bem como seus volumes, volume do gânglio, a densidade neuronal e densidade de volume neuronal durante o desenvolvimento pós-natal (maturação): animais neonatos, jovens e adultos. Os GCCs foram fixados com solução de formoldeído (4%) em PBS, embebidos em solução de ágar e seccionados sistemática, uniforme e aleatoriamente para a aplicação dos métodos estereológicos entre os quais disector e rotator ópticos. para a estimativa da densidade e do volume neuronal, respectivamente. Houve diferença significativa entre os grupos etários para os parâmetros: volume ganglionar, número total de neurônios binucleados, volume neuronal médio de neuronios mono e binucleados e densidade de volume neuronal. A conclusão é de que a idade influencia quantitativamente a dinamica neuronal do GCC de cutias e futuramente estes dados servirão como base para a investigação da ocorrência de divisão celular durante o período pós-natal em roedores. / The present study was pursued in nine left cranial cervical ganglia (CCG) of male cutias (Dasyprocta aguti) obtained from the animal house of the Universidade Federal Rural do Semi-Árido Nordestina em Mossoró- RN. The number of CCG neurons as well as their volume, ganglion volume, numerical density and neuronal volume density were estimated during the post-natal development (maturation), in neonates, young and adult animals, by using 3-D design-based stereological methods, e.g., optical disector and optical rotator. Briefly, CCGs were fixed with a 4% formaldehyde solution in PBS, embedded in a 10% agar solution and exhaustively vibrosectioned (SURS) in order to accordingly perform the relevant stereological estimations. There were significant difference between age groups for the follow parameters: ganglion volume, total number of binucleated neurons, mean neuronal volume of mono and binucleated neurons and volume density of neurons. The conclusion is of that the age quantitative influences the dinamic of neuronal cells of the GCC of agoutis. In the future these data will serve as basis for the inquiry of the occurrence of cellular division during the post-natal period in rodents.

Les microvaisseaux musculaires sont souvent considérés comme une source de nutriments et d'oxygène pour le muscle en croissance et ils semblent être conservés de façon stéréotypée. L'unité microvasculaire du muscle sain et adulte est composée de 6 à 8 capillaires. Dans Gitiaux, et al. (2013) nous montrons que l'organisation et la taille de l'unité microvasculaire sont strictement similaires chez l'homme et la souris. Dans le muscle squelettique adulte, la majorité des cellules satellites sont proches des péricytes et certaines d'entre elles semblent pouvoir établir des contacts directs temporaires avec les péricytes. In vitro, les cellules endothéliales induisent l'activation et la prolifération des cellules satellites en sécrétant de l'Angpt-2 et du PDGF-BB, alors que les péricytes induisent la quiescence et la différenciation des cellules satellites, par l'Angpt-1 et l'IGF-1 respectivement. Ces effets ont été confirmés in vivo, en utilisant les modèles murin Tg:NG2Cre/+::R26RiDTR, Tg:NG2Cre/+::IGF1del/+ et Tg:TNAPCreERT2/+::Angpt1del/+, dans lesquels il existe une hypotrophie musculaire et une activation des cellules satellites. Tous ces résultats soutiennent le dogme que « des cellules souches soutiennent d'autre cellules souches ». / Muscle microvasculature is often considered solely as a source of nutrients and oxygen for growing muscle cells and seems to be stereotypically conserved between human and mouse. The adult normal muscle microvascular unit is formed of 6–8 capillaries. In Gitiaux, et al. (2013) we show that microvascular unit organization and size are strikingly similar in human and small animals. In the adult skeletal muscle, the majority of satellite cells are close neighbors of pericytes and some of them are probably able to establish temporary direct contacts with pericytes. During post-natal development, in human and mice, pericytes and satellite cells become progressively closer. In vitro, endothelial cells induce satellite cell activation and proliferation through Angpt-2 and PDGF-BB, while pericytes induce quiescence through Angpt-1 and differentiation of satellite cells through IGF-1. These effects are confirmed by in vivo experiments using Tg:NG2Cre/+::R26RiDTR, Tg:NG2Cre/+::IGF1del/+ and Tg:TNAPCreERT2/+::Angpt1del/+ mice, which exhibit muscle hypotrophy and satellite cell activation. All these results support the emerging concept that “stem cells support other stem cells”.