Ventilation-induced changes correlate to pulmonary vascular response and VEGF, VEGFR-1/2, and eNOS expression in the rat model of postnatal hypoxia

Neonatal asphyxia occurs due to reduction in oxygen supply to vital organs in the newborn. Rapid restoration of oxygen to the lungs after a long period of asphyxia can cause lung injury and decline of respiratory function, which result from the activity of molecules that induce vascular changes in the lung such as nitric oxide (NO) and vascular endothelial growth factors (VEGF). In this study, we evaluated the pulmonary and vascular morphometry of rats submitted to the model of neonatal asphyxia and mechanical ventilation, their expression of pulmonary VEGF, VEGF receptors (VEGFR-1/VEGFR-2), and endothelial NO synthase (eNOS). Neonate Sprague-Dawley rats (CEUA #043/2011) were divided into four groups (n=8 each): control (C), control submitted to ventilation (CV), hypoxia (H), and hypoxia submitted to ventilation (HV). The fetuses were harvested at 21.5 days of gestation. The morphometric variables measured were body weight (BW), total lung weight (TLW), left lung weight (LLW), and TLW/BW ratio. Pulmonary vascular measurements, VEGFR-1, VEGFR-2, VEGF, and eNOS immunohistochemistry were performed. The morphometric analysis showed decreased TLW and TLW/BW ratio in HV compared to C and H (P<0.005). Immunohistochemistry showed increased VEGFR-2/VEGF and decreased VEGFR-1 expression in H (P<0.05) and lower eNOS expression in H and HV. Median wall thickness was increased in H, and the expression of VEGFR-1, VEGFR-2, VEGF, and eNOS was altered, especially in neonates undergoing H and HV. These data suggested the occurrence of arteriolar wall changes mediated by NO and VEGF signaling in neonatal hypoxia.

Relationships between dendritic morphology, spatial distribution and firing patterns in rat layer 1 neurons

The cortical layer 1 contains mainly small interneurons, which have traditionally been classified according to their axonal morphology. The dendritic morphology of these cells, however, has received little attention and remains ill defined. Very little is known about how the dendritic morphology and spatial distribution of these cells may relate to functional neuronal properties. We used biocytin labeling and whole cell patch clamp recordings, associated with digital reconstruction and quantitative morphological analysis, to assess correlations between dendritic morphology, spatial distribution and membrane properties of rat layer 1 neurons. A total of 106 cells were recorded, labeled and subjected to morphological analysis. Based on the quantitative patterns of their dendritic arbor, cells were divided into four major morphotypes: horizontal, radial, ascendant, and descendant cells. Descendant cells exhibited a highly distinct spatial distribution in relation to other morphotypes, suggesting that they may have a distinct function in these cortical circuits. A significant difference was also found in the distribution of firing patterns between each morphotype and between the neuronal populations of each sublayer. Passive membrane properties were, however, statistically homogeneous among all subgroups. We speculate that the differences observed in active membrane properties might be related to differences in the synaptic input of specific types of afferent fibers and to differences in the computational roles of each morphotype in layer 1 circuits. Our findings provide new insights into dendritic morphology and neuronal spatial distribution in layer 1 circuits, indicating that variations in these properties may be correlated with distinct physiological functions.

Avaliação da atividade cicatrizante do óleo de pequi (Caryocar coriaceum Wittm) em feridas cutâneas produzidas experimentalmente em ratos / Evaluation of the healing activity of pequi (Caryocar coriaceum Wittm) oil in cutaneous wounds induced experimentally in rats

O objetivo deste estudo foi demonstrar os efeitos do tratamento tópico do creme à base de óleo de pequi (Caryocar coriaceum Wittm) utilizando 40 ratos (Rattus norvegicus albinus) da linhagem Wistar, machos, com 60 dias de idade. Esses foram divididos em dois grupos: I) composto por 20 ratos com feridas cutâneas tratados com aplicação tópica do creme base com 10% de óleo de pequi; II) com o mesmo número de animais que receberam a aplicação tópica do creme base sem o óleo de pequi. Após antissepsia e anestesia local foi produzida cirurgicamente ferida circular de 1 cm de diâmetro na região dorso lombar. As lesões cutâneas foram avaliadas sob o aspecto clínico, morfométrica e histológico no 3o, 7o, 14o e 21o dias pós-operatório. No grupo tratado com creme à base de óleo de pequi houve aceleração na evolução do processo cicatricial. As feridas dos animais desse grupo apresentaram redução significativa a partir do décimo quarto dia pós-operatório, bem como foram verificados nesse período achados histológicos característicos da etapa final do processo de cicatrização tais como: acentuada quantidade de fibroblastos, fibras colágenas e completo processo de reepitelização, enquanto que as feridas do grupo controle necessitaram de mais tempo para resolução do processo cicatricial.

The main objective of this study was to demonstrate the effects of topical treatment with ointment containing pequi oil (Caryocar coriaceum Wittm), using 40 male 60-day-old mice (Rattus norvegicus albinus) from the Wistar line. These were divided into two groups: I) composed by 20 mice with cutaneous wounds treated by topical application of the ointment based on 10% pequi oil; II) the same number of mice, receiving the topical application of ointment without pequi oil. After antisepsis and local anesthesia, round 1-cm-diameter wounds were made on the lower back region. The wounds were evaluated in regard to clinical, morphometric and histological aspects on the 3rd, 7th, 14th and 21st postoperative days. The group treated with the pequi ointment presented acceleration in the healing process. The animals' wounds of this group showed a meaningful reduction from the 14th postoperative day, when histological characteristics from the ending of the healing process were noted, such as a large amount of fibroblasts, collagen fibers and a complete process of reepithelialization, while the wounds of the control group needed more time for the healing process.