Histomorphometry of encephalic meninges of Wistar rats in different bands

O desenvolvimento do sistema nervoso é bastante complexo, existindo poucos estudos sobre a organização dos envoltórios cerebrais relacionados ao crescimento encefálico. Utilizando como modelo experimental o rato, analisaram-se os diferentes aspectos estruturais e morfométricos da paquimeninge e leptomeninge durante o processo de envelhecimento. Foram utilizados quatro grupos de ratos em diferentes faixas etárias e analisadas as meninges em microscopias de luz e eletrônica. Verificamos que o grupo de ratos adultos apresentou uma maior área de fibras colágenas tanto do tipo I e quanto do tipo III, em relação aos outros grupos. Encontramos também que as fibras colágenas do tipo III em todos os grupos analisados ocupam uma maior área quando comparados com as fibras do tipo I. Os resultados revelam que a coloração de Weigert Oxona, que mostra fibras elásticas, elaunínicas e oxitalânicas, apresentou uma diferença estatisticamente maior de fibras quando comparados com as colorações de Weigert e Verhoeff, que mostra fíbras elaunínicas e elásticas, respectivamente. Os resultados ultra-estruturais demonstraram a presença de muitos fibroblastos e mitocôndrias tanto na paquimeninge como nas leptomeninges dos grupos de ratos neonatos e adultos, indicativo de alta atividade celular e conseqüentemente, intensa formação de tecido conjuntivo. Como as fibras colágenas do tipo III atuam na manutenção da estrutura de tecidos delicados e expansíveis, o estudo mostra que as funções das meninges encefálicas não estão relacionadas apenas com a resistência a trações e tensões a que estão sujeitas o encéfalo. Mas também a função relacionada com a distensibilidade dos vasos meníngeos e cerebrais de acordo com a necessidade do aporte sanguíneo em diversas funções específicas regionais do tecido nervoso.The development of the nervous system is very complex and there are few studies about the organization of the brain envoltories related to the encephalus growing. Using the rat as an animal model, it was proposed to evaluate the several structural aspects of paquimeninge and leptomeninge in different ages. It was used 4 groups of different ages and processed according to the techniques of the light and transmission microscopy. It was verified that the adult rats present a higher area of collagen fibers of type I and III, if compared to the others groups. It was found that, the collagen fibers of type III occupy, in all analyzed groups, a higher area when compared to type I fibers. The results reveal that the Weigert Oxona's staining, which shows elastics, elauninics, and oxitalanics fibers, showed a statistically difference when compared to the Weigert's staining and Verhoeff's staining that show elauninics and elastics fibers, respectively. The ultra-structural aspects demonstrated the presence of many fibroblasts and mitochondria in the paquimeninge and also in the leptomeninges of the neonats and adults groups, indicating the high cellular activity and consequently, an intense formation of conjunctive tissue. As collagen fibers of type III acting on the structural maintenance of delicate and expansive tissues, the study shows that the function of the encephalic meninges are not only related to the to resistance to tractions and tensions that the encephalus is subjected. But also the function related to the distensibility of the meningeos and brain vases according to the sanguineous apport in several specific functions of the nervous system

Estudo micro-mesoscópico da parede lateral do seio cavernoso humano Human cavernous sinus: micro-mesoscopic study of the lateral wall

Os autores estudam as estruturas contidas no seio cavernoso humano, tanto em seu interior como na sua parede lateral, através de cortes frontais seriados espessos. Mostram a importância desta parede que é freqüentemente usada como via de acesso cirúrgico às afecções presentes nesta estrutura venosa da dura-máter<br>The authors studied the structures of human cavernous sinus in its interior as well as on the lateral wall, utilizing thick, frontal, sequential sections. They show the significance of this wall, frequently used as surgical accessway to diseases encountered within this venous structure of the dura-mater

Estudo da conectividade entre o nervo occipital maior e estruturas adjacentes considerações anátomo-clínicas

A fim de oferecer substrato anatômico que contribua para a interpretação clínica da cefaléia de origem cervical, estudo macro-mesoscópico do nervo occipital maior e da sua região de emergência subcutânea foi realizado. Observamos que, ao longo de sua estratigrafia, esse nervo descreve ângulos e mudanças de direção, que podem representar pontos críticos na etiologia da dor occipital; na região de sua emergência subcutânea forma, com a artéria e a veia occipital, feixe vásculo-nervoso envolvido por bainha de tecido conjuntivo fibroso, a qual mantém relações de continuidade e contigüidade com epimísio e perimísio adjacentes. A partir dos resultados encontrados, fazemos considerações anátomo-clínicas

B1 and AT1 receptors expression in aorta and aortic smooth muscle cells (VSMC) primary culture.

<p>Bar graph shows B1 receptor (B1R) [A] and AT1 receptor [B] mRNA levels in aortas from control, ANG II (400 ng/Kg/min), ANG II (400 ng/Kg/min) + DAL (350 ng/Kg/min) and ANG II (400 ng/Kg/min) + LOS (10 mg/Kg/day) rats. The receptors mRNA expression was calculated from the cycle threshold (Ct) value using the Δ²Ct method for quantification. Values were normalized against β-actin mRNA. Data represented mean±SEM; n = 5–7 for each group; *P<0.05 vs control. [C] Bar graph shows the temporal effects of ANG II (100 nM, 0–24 h) on protein B1R expression in aortic VSMC. [D] Bar graph shows B1R expression in aortic VSMC after stimulation with ANG II (100 nM, 2 h), in the presence or not of AT1 antagonist, losartan (LOS – 10 µM). B1R expression was normalized against the housekeeping protein β-actin. Data are presented as mean±SEM of 4 experiments. *P<0.05 vs. control.</p

Effects of des-Arg⁹-bradykinin (DABK) and angiotensin II (ANG II) vascular smooth muscle cells (VSMC) growth.

<p>[A] Aortic VSMC from Wistar rats treated with ANG II and/or DABK at low concentration (0.1 nM) in the presence or not of losartan (LOS – 10 µM), des-arg9-leu8-bradykinin (DAL – 10 µM) and TIRON (1 mM). Bar graph shows PCNA expression normalized against the housekeeping protein β-actin. Results are represented as mean±SEM of 4 experiments. *P<0.05 vs Vehicle. [B] Aortic VSMC from Wistar rats with ANG II at high concentration (100 nM) in the presence or not of losartan (LOS – 10 µM), des-arg9-leu8-bradykinin (DAL – 10 µM). Bar graph shows PCNA expression normalized against the housekeeping protein β-actin. Results are expressed as mean±SEM of 5 experiments. *P<0.05 vs vehicle. [C] [H3] leucine incorporation in VSMC treated with ANG II and/or DABK at low concentration (0.1 nM) in the presence or not of losartan (LOS – 10 µM) and des-arg9-leu8-bradykinin (DAL – 10 µM) and VSMC treated with ANG II at high concentration (100 nM). Results are expressed as mean±SEM of 3 experiments and *P<0.05 vs vehicle.</p

B1 receptor antagonism prevented angiotensin II (ANG II) effect in aorta.

<p>[A] Fluorescence microscopy of aortic transverse sections after incubation with DHE. [B] Ratios of 2-hydroxyethidium/dihydroethidine (EOH/DHE) and ethidium/dihydroethidine (E/DHE) obtained by HPLC analysis from aortic segments. Data are expressed as mean ± SEM of 5 rats for each group. *P<0.05 vs control and **P<0.05 vs. ANG II [C] Bar graph shows the ratio of phosphorylated/total ERK1/2 that was used as an indicator of ERK1/2 activity. Data are expressed as mean ± SEM of 6 rats for each group. *P<0.05 vs control and **P<0.05 vs. ANG II.</p

Effect of angiotensin II (ANG II) and des-Arg⁹-bradykinin (DABK) on superoxide anion generation in VSMC.

<p>[A] Bar graph demonstrates the effects of ANG II (0.1 nM), DABK (0.1 nM) and ANG II-DABK co-stimulation for 5 min, in the presence of either vehicle, AT1 antagonist losartan (LOS – 10 µM), B1 receptor antagonist des-Arg⁹-Leu⁸-bradykinin (DAL – 10 µM) or superoxide anion scavenger (TIRON - 1 mM) on superoxide anion generation. Results were expressed as mean±SEM of 5 experiments. *P<0.05 vs vehicle. [B] Bar graph demonstrates the effects of ANG II (100 nM) stimulation for 5 min, in the presence of vehicle, AT1 antagonist, losartan (LOS – 10 µM), or B1 receptor antagonist, des-Arg⁹-Leu⁸-bradykinin (DAL – 10 µM). Results are represented as mean ± SEM of 5 experiments. *P<0.05 vs vehicle.</p

An interaction of renin-angiotensin and kallikrein-kinin systems contributes to vascular hypertrophy in angiotensin ii-induced hypertension: in vivo and in vitro studies

The kallikrein-kinin and renin-angiotensin systems interact at multiple levels. In the present study, we tested the hypothesis that the B1 kinin receptor (B1R) contributes to vascular hypertrophy in angiotensin II (ANG II)–induced hypertension, through a mechanism involving reactive oxygen species (ROS) generation and extracellular signal-regulated kinase (ERK1/2) activation. Male Wistar rats were infused with vehicle (control rats), 400 ng/Kg/min ANG II (ANG II rats) or 400 ng/Kg/min ANG II plus B1 receptor antagonist, 350 ng/Kg/min des-Arg9-Leu8-bradykinin (ANGII+DAL rats), via osmotic mini-pumps (14 days) or received ANG II plus losartan (10 mg/Kg, 14 days, gavage - ANG II+LOS rats). After 14 days, ANG II rats exhibited increased systolic arterial pressure [(mmHg) 184±5.9 vs 115±2.3], aortic hypertrophy; increased ROS generation [2-hydroxyethidium/dihydroethidium (EOH/DHE): 21.8±2.7 vs 6.0±1.8] and ERK1/2 phosphorylation (% of control: 218.3±29.4 vs 100±0.25]. B1R expression was increased in aortas from ANG II and ANG II+DAL rats than in aortas from the ANG II+LOS and control groups. B1R antagonism reduced aorta hypertrophy, prevented ROS generation (EOH/DHE: 9.17±3.1) and ERK1/2 phosphorylation (137±20.7%) in ANG II rats. Cultured aortic vascular smooth muscle cells (VSMC) stimulated with low concentrations (0.1 nM) of ANG II plus B1R agonist exhibited increased ROS generation, ERK1/2 phosphorylation, proliferating-cell nuclear antigen expression and [H3]leucine incorporation. At this concentration, neither ANG II nor the B1R agonist produced any effects when tested individually. The ANG II/B1R agonist synergism was inhibited by losartan (AT1 blocker, 10 µM), B1R antagonist (10 µM) and Tiron (superoxide anion scavenger, 10 mM). These data suggest that B1R activation contributes to ANG II-induced aortic hypertrophy. This is associated with activation of redox-regulated ERK1/2 pathway that controls aortic smooth muscle cells growth. Our findings highlight an important cross-talk between the DABK and ANG II in the vascular system and contribute to a better understanding of the mechanisms involved in vascular remodeling in hypertension