Postnatal development of rats exposed to fluoxetine or venlafaxine during the third week of pregnancy

The aim of the present study was to compare the toxic effects of fluoxetine (F) (8 and 16 mg/kg) and venlafaxine (V) (40 and 80 mg/kg) administered during the third week of pregnancy on early development of rats. Both antidepressants were administered by gavage on pregnancy days 15 to 20 to groups of 10 to 12 animals each. Duration of gestation, food and water consumption, number of live pups and birth weight were recorded. Litters were culled to six pups at birth (day 1) and followed for growth until weaning (day 25). On day 60, a male and a female from each litter were injected with the 5-HT1 agonist, 5-methoxy-N,N-dimethyltryptamine (6 mg/kg, ip) and the serotonergic syndrome was graded. Fluoxetine but not venlafaxine reduced the duration of pregnancy when compared to the control (C) group (F = 21.1 days and C = 21.6 days, mean, P<0.02; maximum = 22 days and minimum = 21 days in both groups). The highest doses of both fluoxetine, 16 mg/kg (F16), and venlafaxine, 80 mg/kg (V80), reduced the food intake of pregnant rats, resulting in different rates of body weight gain during treatment (from pregnancy day 15 to day 20): F16 = 29.0 g, V80 = 28.7 g vs C = 39.5 g (median). Birth weight was influenced by treatment and sex (P<0.05; two-way ANOVA). Both doses of fluoxetine or venlafaxine reduced the body weight of litters; however, the body weight of litters from treated dams was equal to the weight of control litters by the time of weaning. At weaning there was no significant difference in weight between sexes. There was no difference among groups in number of live pups at birth, stillbirths, mortality during the lactation period or in the manifestation of serotonergic syndrome in adult rats. The occurrence of low birth weight among pups born to dams which did not show reduced food ingestion or reduction of body weight gain during treatment with lower doses of fluoxetine or venlafaxine suggests that these drugs may have a deleterious effect on prenatal development when administered during pregnancy. In addition, fluoxetine slightly but significantly affected the duration of pregnancy (about half a day), an effect not observed in the venlafaxine-treated groups.

Experimental myocardial hypertrophy induced by a minimally invasive ascending aorta coarctation

Ascending aorta coarctation was produced by a minimally invasive technique in rabbits. Animal mortality was 5%. Morphometric and hemodynamic parameters were evaluated. A parabiotically isolated heart model was used to assess the hemodynamic parameters. Left ventricular weight/body weight ratio and muscle area showed clear evidence of hypertrophy when compared to control. The hemodynamic changes in the isolated heart model suggested decreased diastolic and systolic function in the coarcted group. The present model produced hypertrophy with low mortality rates as a result of its less invasive nature.

Development according to pubertal stage in Brazilian children and adolescents with short-term diabetes

The anthropometric status and metabolic control of 51 recently diagnosed Brazilian schoolchildren with type 1 diabetes (DM1), during the first 5 years of the disease, were compared with those of normal children (60 girls and 132 boys) belonging to the same environmental condition and pubertal stage. Metabolic control was evaluated on the basis of fasting plasma glucose (FPG) and HbA1c levels. The criteria of the National Center for Health Statistics were used for anthropometric evaluation. FPG (205 ± 51 mg/dl for girls vs 200 ± 34 mg/dl for boys) and % above upper normal limit of median HbA1c (1.8% for girls vs 2.5% for boys with diabetes) were not significantly different during follow-up. The Z-score of the last height evaluation was lower in the girls' group (-0.14 vs -0.53, P<0.05). By forward stepwise analysis, the Z-score of the initial height was statistically significant as a determinant factor for height at the end of the study in both girls and boys with DM1. The Z-score of weight at last evaluation was not different from that at diagnosis in either sex. However, analysis according to pubertal stage showed a tendency to a weight increase in the girls. The weight recovery and height loss in girls with DM1 follows the trend of the normal Brazilian population.

Ventilation with high tidal volume induces inflammatory lung injury

Mechanical ventilation with high tidal volumes (V T) has been shown to induce lung injury. We examined the hypothesis that this procedure induces lung injury with inflammatory features. Anesthetized male Wistar rats were randomized into three groups: group 1 (N = 12): V T = 7 ml/kg, respiratory rate (RR) = 50 breaths/min; group 2 (N = 10): V T = 21 ml/kg, RR = 16 breaths/min; group 3 (N = 11): V T = 42 ml/kg, RR = 8 breaths/min. The animals were ventilated with fraction of inspired oxygen of 1 and positive end-expiratory pressure of 2 cmH2O. After 4 h of ventilation, group 3, compared to groups 1 and 2, had lower PaO2 [280 (range 73-458) vs 517 (range 307-596), and 547 mmHg (range 330-662), respectively, P<0.05], higher wet lung weight [3.62 ± 0.91 vs 1.69 ± 0.48 and 1.44 ± 0.20 g, respectively, P<0.05], and higher wet lung weight/dry lung weight ratio [18.14 (range 11.55-26.31) vs 7.80 (range 4.79-12.18), and 6.34 (range 5.92-7.04), respectively, P<0.05]. Total cell and neutrophil counts were higher in group 3 compared to groups 1 and 2 (P<0.05), as were baseline TNF-alpha concentrations [134 (range <10-386) vs 16 (range <10-24), and 17 pg/ml (range <10-23), respectively, P<0.05]. Serum TNF-alpha concentrations reached a higher level in group 3, but without statistical significance. These results suggest that mechanical ventilation with high V T induces lung injury with inflammatory characteristics. This ventilatory strategy can affect the release of TNF-alpha in the lungs and can reach the systemic circulation, a finding that may have relevance for the development of a systemic inflammatory response.

Weight of preterm newborns during the first twelve weeks of life

A longitudinal and prospective study was carried out at two state-operated maternity hospitals in Belo Horizonte during 1996 in order to assess the weight of preterm appropriate-for-gestational-age newborns during the first twelve weeks of life. Two hundred and sixty appropriate-for-gestational-age preterm infants with birth weight <2500 g were evaluated weekly. The infants were divided into groups based on birth weight at 250-g intervals. Using weight means, somatic growth curves were constructed and adjusted to Count's model. Absolute (g/day) and relative (g kg-1 day-1) velocity curves were obtained from a derivative of this model. The growth curve was characterized by weight loss during the 1st week (4-6 days) ranging from 5.9 to 13.3% (the greater the percentage, the lower the birth weight), recovery of birth weight within 17 and 21 days, and increasingly higher rates of weight gain after the 3rd week. These rates were proportional to birth weight when expressed as g/day (the lowest and the highest birth weight neonates gained 15.9 and 30.1 g/day, respectively). However, if expressed as g kg-1 day-1, the rates were inversely proportional to birth weight (during the 3rd week, the lowest and the highest weight newborns gained 18.0 and 11.5 g kg-1 day-1, respectively). During the 12th week the rates were similar for all groups (7.5 to 10.2 g kg-1 day-1). The relative velocity accurately reflects weight gain of preterm infants who are appropriate for gestational age and, in the present study, it was inversely proportional to birth weight, with a peak during the 3rd week of life, and a homogeneous behavior during the 12th week for all weight groups.

Hypotrophy of conduit artery walls of the offspring of nitric oxide-defective rats

The objective of the present study was to investigate the structure of the arterial walls of the offspring stemming from nitric oxide (NO)-defective hypertensive parents. The parents were treated with N G-nitro-L-arginine methyl ester (40 mg kg-1 day-1) for 5 weeks. Blood pressure was measured noninvasively in six 30-day-old rats and nine age-matched controls. The cardiovascular system was perfused with glutaraldehyde at 120 mmHg. The thoracic aorta and carotid artery were processed for electron microscopy, and geometry was determined by light microscopy. Endothelial cells, smooth muscle cells (SMC) and extracellular matrix (ECM) were determined by the point counting method in electron micrographs of the carotid artery. The blood pressure of experimental offspring was 150.0 ± 2.3 vs 104.6 ± 2.1 mmHg (P < 0.01) for the controls and their heart/body weight ratio of 3.9 ± 0.1 vs 4.4 ± 0.2 (P < 0.05) for the controls indicated cardiac hypotrophy. The wall thickness (tunica intima and media) of the thoracic aorta and carotid artery of experimental offspring was decreased to 78.9% (P < 0.01) and 83.8% (P < 0.01), respectively, compared to controls, as confirmed by a respective cross-sectional area of 85.3% (P < 0.01) and 84.1% (P < 0.01). The wall thickness/inner diameter ratio was reduced to 75% (P < 0.01) in the thoracic artery and to 81.5% (P < 0.01) in the carotid artery. No change in endothelial cell volume density or ECM was observed in the tunica intima of the carotid artery, and SMC volume density was lower in the tunica media (37.6 ± 0.9 vs 44.7 ± 1.1% for controls, P < 0.01), indicating compromised SMC development. Interference with arginine metabolism, a decrease in NO, and other factors are possible mechanisms underlying the structural alterations of the cardiovascular system of offspring from NO-defective hypertensive rats.

Effect of hyperbaric oxygenation on the regeneration of the liver after partial hepatectomy in rats

The aim of the present study was to assess the influence of hyperbaric oxygenation (HBO) on rat liver regeneration before and after partial hepatectomy. Rats were sacrificed 54 h after 15% hepatectomy, liver and body weights were measured, and serum alanine transaminase (ALT) and aspartate transaminase (AST) activity and albumin levels were determined. The lipid peroxide level, as indicated by malondialdehyde production in the remnant liver was measured, and liver sections were analyzed by light microscopy. Five groups of 10 rats in each group were studied. The preHBO and pre-hyperbaric pressure (preHB) groups were treated before partial hepatectomy with 100% O2 and 21% O2, respectively, at 202,650 pascals, daily for 3 days (45 min/day). The control group was not treated before partial hepatectomy and recovered under normal ambient conditions after the procedure. Groups postHBO and postHB were treated after partial hepatectomy with HBO and HB, respectively, three times (45 min/day). The preHBO group presented a significant increase in the initiation of the regeneration process of the liver 54 h postoperatively. The liver/body weight ratio was 0.0618 ± 0.0084 in the preHBO compared to 0.0517 ± 0016 g/g in the control animals (P = 0.016). In addition, the preHBO group showed significant better liver function (evaluated by the lowest serum ALT and AST activities, P = 0.002 and P = 0.008, respectively) and showed a significant decrease in serum albumin levels compared to control (P < 0.001). Liver lipid peroxide concentration was lowest in the preHBO group (P < 0.001 vs control and postHBO group) and light microscopy revealed that the composition of liver lobules in the preHBO group was the closest to normal histological features. These results suggest that HBO pretreatment was beneficial for rat liver regeneration after partial hepatectomy.

Cyclosporin-A does not affect skeletal muscle mass during disuse and recovery

Cyclosporin-A (CsA) is an immunosuppressive drug that acts as an inhibitor of calcineurin, a calcium phosphatase that has been suggested to play a role in skeletal muscle hypertrophy. The aim of the present study was to determine the effect of CsA administration (25 mg kg-1 day-1) on skeletal muscle mass and phenotype during disuse and recovery. Male Wistar rats received vehicle (N = 8) or CsA (N = 8) during hind limb immobilization (N = 8) and recovery (N = 8). Muscle weight (dry/wet) and cross-sectional area were evaluated to verify the effect of CsA treatment on muscle mass. Muscle phenotype was assessed by histochemistry of myosin ATPase. CsA administration during immobilization and recovery did not change muscle/body weight ratio in the soleus (SOL) or plantaris (PL). Regarding muscle phenotype, we observed a consistent slow-to-fast shift in all experimental groups (immobilized only, receiving CsA only, and immobilized receiving CsA) as compared to control in both SOL and PL (P < 0.05). During recovery, no difference was observed in SOL or PL fiber type composition between the experimental recovered group and recovered group receiving CsA compared to their respective controls. Considering the muscle/body weight ratio, CsA administration does not maximize muscle mass loss induced by immobilization. Our results also indicate that CsA fails to block skeletal muscle regrowth after disuse. The present data suggest that calcineurin inhibition by CsA modulates muscle phenotype rather than muscle mass.

Influence of intrauterine and extrauterine growth on neurodevelopmental outcome of monozygotic twins

There have been indications that intrauterine and early extrauterine growth can influence childhood mental and motor function. The objective of the present study was to evaluate the influence of intrauterine growth restriction and early extrauterine head growth on the neurodevelopmental outcome of monozygotic twins. Thirty-six monozygous twin pairs were evaluated at the corrected age of 12 to 42 months. Intrauterine growth restriction was quantified using the fetal growth ratio. The effects of birth weight ratio, head circumference at birth and current head circumference on mental and motor outcomes were estimated using mixed-effect linear regression models. Separate estimates of the between (interpair) and within (intrapair) effects of each measure on development were thus obtained. Neurodevelopment was assessed with the Bayley Scales of Infant Development, 2nd edition, by a psychologist blind to the exposure. A standardized neurological examination was performed by a neuropediatrician who was unaware of the exposures under investigation. After adjustment, birth weight ratio and head circumference at birth were not associated with motor or mental outcomes. Current head circumference was associated with mental but not with motor outcomes. Only the intrapair twin effect was significant. An increase of 1 cm in current head circumference of one twin compared with the other was associated with 3.2 points higher in Mental Developmental Index (95%CI = 1.06-5.32; P < 0.03). Thus, no effect of intrauterine growth was found on cognition and only postnatal head growth was associated with cognition. This effect was not shared by the co-twin.

Kinetics of cardiac and vascular remodeling by spontaneously hypertensive rats after discontinuation of long-term captopril treatment

Angiotensin-converting enzyme inhibitors reduce blood pressure and attenuate cardiac and vascular remodeling in hypertension. However, the kinetics of remodeling after discontinuation of the long-term use of these drugs are unknown. Our objective was to investigate the temporal changes occurring in blood pressure and vascular structure of spontaneously hypertensive rats (SHR). Captopril treatment was started in the pre-hypertensive state. Rats (4 weeks) were assigned to three groups: SHR-Cap (N = 51) treated with captopril (1 g/L) in drinking water from the 4th to the 14th week; SHR-C (N = 48) untreated SHR; Wistar (N = 47) control rats. Subgroups of animals were studied at 2, 4, and 8 weeks after discontinuation of captopril. Direct blood pressure was recorded in freely moving animals after femoral artery catheterism. The animals were then killed to determine left ventricular hypertrophy (LVH) and the aorta fixed at the same pressure measured in vivo. Captopril prevented hypertension (105 ± 3 vs 136 ± 5 mmHg), LVH (2.17 ± 0.05 vs 2.97 ± 0.14 mg/g body weight) and the increase in cross-sectional area to luminal area ratio of the aorta (0.21 ± 0.01 vs 0.26 ± 0.02 μm²) (SHR-Cap vs SHR-C). However, these parameters increased progressively after discontinuation of captopril (22nd week: 141 ± 2 mmHg, 2.50 ± 0.06 mg/g, 0.27 ± 0.02 μm²). Prevention of the development of hypertension in SHR by using captopril during the prehypertensive period prevents the development of cardiac and vascular remodeling. Recovery of these processes follows the kinetic of hypertension development after discontinuation of captopril.

PPM1B and P-IKKβ expression levels correlated inversely with rat gastrocnemius atrophy after denervation

Activated inhibitor of nuclear factor-κB kinase β (IKKβ) is necessary and sufficient for denervated skeletal muscle atrophy. Although several studies have shown that Mg2+/Mn2+-dependent protein phosphatase 1B (PPM1B) inactivated IKKβ, few studies have investigated the role of PPM1B in denervated skeletal muscle. In this study, we aim to explore the expression and significance of PPM1B and phosphorylated IKKβ (P-IKKβ) during atrophy of the denervated gastrocnemius. Thirty young adult female Wistar rats were subjected to right sciatic nerve transection and were sacrificed at 0 (control), 2, 7, 14, and 28 days after denervation surgery. The gastrocnemius was removed from both the denervated and the contralateral limb. The muscle wet weight ratio was calculated as the ratio of the wet weight of the denervated gastrocnemius to that of the contralateral gastrocnemius. RT-PCR and Western blot analysis showed that mRNA and protein levels of PPM1B were significantly lower than those of the control group at different times after the initiation of denervation, while P-IKKβ showed the opposite trends. PPM1B protein expression persistently decreased while P-IKKβ expression persistently increased for 28 days after denervation. PPM1B expression correlated negatively with P-IKKβ expression by the Spearman test, whereas decreasing PPM1B expression correlated positively with the muscle wet weight ratio. The expression levels of PPM1B and P-IKKβ were closely associated with atrophy in skeletal denervated muscle. These results suggest that PPM1B and P-IKKβ could be markers in skeletal muscle atrophy.

Exogenous normal lymph reduces liver injury induced by lipopolysaccharides in rats

The liver is one of the target organs damaged by septic shock, wherein the spread of endotoxins begins. This study aimed to investigate the effects of exogenous normal lymph (ENL) on lipopolysaccharide (LPS)-induced liver injury in rats. Male Wistar rats were randomly divided into sham, LPS, and LPS+ENL groups. LPS (15 mg/kg) was administered intravenously via the left jugular vein to the LPS and LPS+ENL groups. At 15 min after the LPS injection, saline or ENL without cell components (5 mL/kg) was administered to the LPS and LPS+ENL groups, respectively, at a rate of 0.5 mL/min. Hepatocellular injury indices and hepatic histomorphology, as well as levels of P-selectin, intercellular adhesion molecule 1 (ICAM-1), myeloperoxidase (MPO), and Na+-K+-ATPase, were assessed in hepatic tissues. Liver tissue damage occurred after LPS injection. All levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in plasma as well as the wet/dry weight ratio of hepatic tissue in plasma increased. Similarly, P-selectin, ICAM-1, and MPO levels in hepatic tissues were elevated, whereas Na+-K+-ATPase activity in hepatocytes decreased. ENL treatment lessened hepatic tissue damage and decreased levels of AST, ALT, ICAM-1, and MPO. Meanwhile, the treatment increased the activity of Na+-K+-ATPase. These results indicated that ENL could alleviate LPS-induced liver injury, thereby suggesting an alternative therapeutic strategy for the treatment of liver injury accompanied by severe infection or sepsis.

Early neonatal echocardiographic findings in an experimental rabbit model of congenital diaphragmatic hernia

This study aimed to demonstrate that congenital diaphragmatic hernia (CDH) results in vascular abnormalities that are directly associated with the severity of pulmonary hypoplasia and hypertension. These events increase right ventricle (RV) afterload and may adversely affect disease management and patient survival. Our objective was to investigate cardiac function, specifically right ventricular changes, immediately after birth and relate them to myocardial histological findings in a CDH model. Pregnant New Zealand rabbits underwent the surgical procedure at 25 days of gestation (n=14). CDH was created in one fetus per horn (n=16), and the other fetuses were used as controls (n=20). At term (30 days), fetuses were removed, immediately dried and weighed before undergoing four-parameter echocardiography. The lungs and the heart were removed, weighed, and histologically analyzed. CDH animals had smaller total lung weight (P<0.005), left lung weight (P<0.005), and lung-to-body ratio (P<0.005). Echocardiography revealed a smaller left-to-right ventricle ratio (LV/RV, P<0.005) and larger diastolic right ventricle size (DRVS, P<0.007). Histologic analysis revealed a larger number of myocytes undergoing mitotic division (186 vs 132, P<0.05) in CDH hearts. Immediate RV dilation of CDH hearts is related to myocyte mitosis increase. This information may aid the design of future strategies to address pulmonary hypertension in CDH.

Galantamine protects against lipopolysaccharide-induced acute lung injury in rats

Lipopolysaccharide (LPS)-induced endotoxemia triggers the secretion of proinflammatory cytokines and can cause acute lung injury (ALI). The high mobility group box 1 (HMGB1) protein plays an important role as a late mediator of sepsis and ALI. Galantamine (GAL) is a central acetylcholinesterase inhibitor that inhibits the expression of HMGB1. This study evaluated the effects of GAL by measuring levels of inflammatory mediators and observing histopathological features associated with LPS-induced ALI. Sixty 8-10 week old male Sprague-Dawley rats (200-240 g) were randomized into three groups as follows: control group, LPS group (7.5 mg/kg LPS), and LPS+GAL group (5 mg/kg GAL before LPS administration). Histopathological examination of lung specimens obtained 12 h after LPS administration was performed to analyze changes in wet-to-dry (W/D) weight ratio, myeloperoxidase (MPO) activity, and HMGB1 expression level. Additionally, plasma concentrations of tumor necrosis factor-α, interleukin-6, and HMGB1 were measured using an enzyme-linked immunosorbent assay at 0 (baseline), 3, 6, 9, and 12 h after LPS administration. Mortality in the three groups was recorded at 72 h. LPS-induced ALI was characterized by distortion of pulmonary architecture and elevation of MPO activity, W/D weight ratio, and levels of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin-6, and HMGB1. Pretreatment with GAL significantly reduced the LPS-induced lung pathological changes, W/D weight ratio, levels of pro-inflammatory cytokines and MPO activity (ANOVA). Moreover, GAL treatment significantly decreased the mortality rate (ANOVA). In conclusion, we demonstrated that GAL exerted a protective effect on LPS-induced ALI in rats.

Implantation of muscle satellite cells overexpressing myogenin improves denervated muscle atrophy in rats

This study evaluated the effect of muscle satellite cells (MSCs) overexpressing myogenin (MyoG) on denervated muscle atrophy. Rat MSCs were isolated and transfected with the MyoG-EGFP plasmid vector GV143. MyoG-transfected MSCs (MTMs) were transplanted into rat gastrocnemius muscles at 1 week after surgical denervation. Controls included injections of untransfected MSCs or the vehicle only. Muscles were harvested and analyzed at 2, 4, and 24 weeks post-transplantation. Immunofluorescence confirmed MyoG overexpression in MTMs. The muscle wet weight ratio was significantly reduced at 2 weeks after MTM injection (67.17±6.79) compared with muscles injected with MSCs (58.83±5.31) or the vehicle (53.00±7.67; t=2.37, P=0.04 and t=3.39, P=0.007, respectively). The muscle fiber cross-sectional area was also larger at 2 weeks after MTM injection (2.63×103±0.39×103) compared with MSC injection (1.99×103±0.58×103) or the vehicle only (1.57×103±0.47×103; t=2.24, P=0.049 and t=4.22, P=0.002, respectively). At 4 and 24 weeks post-injection, the muscle mass and fiber cross-sectional area were similar across all three experimental groups. Immunohistochemistry showed that the MTM group had larger MyoG-positive fibers. The MTM group (3.18±1.13) also had higher expression of MyoG mRNA than other groups (1.41±0.65 and 1.03±0.19) at 2 weeks after injection (t=2.72, P=0.04). Transplanted MTMs delayed short-term atrophy of denervated muscles. This approach can be optimized as a novel stand-alone therapy or as a bridge to surgical re-innervation of damaged muscles.