Affective Behavior Shows Sex Differences in Mid-adulthood Rats Following Postnatal Immune Stimulation.

Mid-adulthood represents the critical window period usually associated with the development of age-related diseases. Despite several attempts to delineate the pathological mechanisms underlying postnatal immune challenge and altered brain functions, the role of sex-dependent changes in affective behaviors of middle-aged animals requires more attention. In this study, we sought to investigate behavioral and molecular response patterns at mid-adulthood linked to early-life immune activation. Using affective behavioral test batteries, we showed that lipopolysaccharide (LPS)-induced postnatal immune challenge caused anxiety-like behaviors in both male and female Wistar rats at mid-adulthood, whereas only female rats exhibited depression-like behaviors. Our data further demonstrated a significant increase in microglial complexity and increased levels of tumor necrosis factor (TNFα), nitric oxide (NOx), and lipid peroxidation in the prefrontal cortex of female rats compared to their male counterparts and phosphate-buffered saline (PBS) littermate controls. With these results, we established significant interaction between sex differences and LPS-induced alterations in behavior and associated oxidative and immunohistochemical changes. These findings may provide an insight to better understand the neuroimmunological mechanisms of sex-dependent brain pathological manifestations occurring at mid-adulthood.

The sex differences of the behavior response to early Life immune stimulation: Microglia and astrocytes involvement.

It is well known that inflammatory challenge during the prenatal period results in permanent changes in glial cells and behavior in adulthood. However, it is unknown whether inflammatory challenge during the infantile period may have permanent sexually-dimorphic effects on microglia and astrocytes in vivo, which in turn may be associated with sex differences in adult behavior. In this study, we have evaluated whether postnatal injection of lipopolysaccharide (LPS; 250µg/kg, i.p. on postnatal day 14) induces depressive and less anxiety-like behaviors, glial cell activation, pro-inflammatory cytokine (TNF-alpha) secretion and sexually dimorphic responses in adulthood. Postnatal day 14 (P14) male and female Wistar rats received an intraperitoneal (ip) injection of LPS or PBS. Three months later, animals were tested in the Open Field (OF), the Elevated Plus Maze (EPM) and the Forced Swimming Test (FST) to assess the level of anxiety and depression-like behavior. Hippocampal proinflammatory cytokine TNF-alpha concentration and the number of astrocytes and microglia were estimated in the dentate gyrus, CA1, and CA3 in two regions of the hippocampus (ventral and dorsal). Our results showed that the administration of LPS resulted in less anxiety and depression-like behavior in males but not in females. However, the LPS-administration increased the number of microglia in the dorsal and ventral hippocampus areas in females more than male, while no significant differences in TNFα level had been detected between the LPS-rats treated and their controls. Interestingly, LPS resulted in an increase in the number of astrocytes in both areas of the hippocampus in a female. While in a male, our results showed a decrease in astrocytes number in the dorsal hippocampus, but no significant differences observed in ventral hippocampus. These findings indicate that an immune challenge in infantile rats induces a ventral and dorsal hippocampus damage in female more than in male, without affecting significantly the affective behavior changes in the female. The results also showed that small changes in the male hippocampus can affect the behavior and induce a depression-like behavior.

Thymelaea lythroides extract attenuates microglial activation and depressive-like behavior in LPS-induced inflammation in adult male rats.

Thymelaea lythroides extract is widely used as a traditional folk medicine in Morocco, especially for the treatment of diabetes, rheumatism and Inflammatory disease. The aim of the study is to evaluate the possible effect of methanolic extract of Thymelaea lythroides in repressing the inflammatory responses and long-lasting depression-like behavior associated with neuroinflammation in adult rats after neonatal LPS exposure. Male rat pups were treated systemically with either LPS (250??g/kg) or vehicle (phosphate buffer saline) on postnatal day 14. Six hours later, the LPS groups were assigned to intraperitoneal (ip) injection of Minocycline (50?mg/kg) or Thymelaea lythroides (200?mg/kg). Thereafter, in adulthood (postnatal days 90-97), the spontaneous locomotor activity and depression-like behavior were assessed successively in open field and forced swim tests. The levels of proinflammatory cytokines, oxidative damage, and activation of microglia were determined in the hippocampus (HP) of male rats on (PND90-97). Our results showed that open field hypoactivity and increased immobility period in LPS-induced adult rats were normalized on treatment with Thymelaea lythroides and minocycline. Both treatments attenuate the overactivated microglial cells in the CA1 and CA3 of hippocampus (HP) and significantly reduced the oxidative-nitrosative stress markers and cytokine (TNF ?) production in the HP. Thymelaea lythroides seems to have similar neuroprotective effects to Minocycline, and such protection may be due to: reduction of oxidative stress, upregulation of inflammatory mediators production, antidepressant behavior which all are associated with neuroinflammation.

Postnatal melatonin treatment protects against affective disorders induced by early-life immune stimulation by reducing the microglia cell activation and oxidative stress.

BACKGROUND: Systemic inflammation induced by neonatal infection may result as long-term hyper-activation of microglial cells followed by an overproduction of pro-inflammatory cytokines, such as tumor necrosis factor-alpha, nitric oxide and lipid peroxidation. Those inflammation mediators can trigger behavioral disruption and/or cognitive disorders. OBJECTIVE: The present work aims to evaluate the effect of melatonin (a cytokine release modulator and antioxidant agent) in the reduction of the prefrontal microglia activation and depressive-like behaviors induced by lipopolysaccharide (LPS) injection in adult rats. RESULTS: The effect of melatonin (5 mg/kg) was compared to minocycline (50 mg/kg), a well-known anti-inflammatory drug with potent inhibitory effect on microglial activation. Our results showed that LPS injection induced a significant increase in prefrontal cortex tumor necrosis factor-alpha and nitric oxide levels. Furthermore, lipid peroxidation and microglial activation were highly increased in the prefrontal cortex compared to control. The melatonin treatment induced a significant decrease on nitric oxide and lipid peroxidation levels in the prefrontal cortex and significant decrease on tumor necrosis factor-alpha and microglia activation. Melatonin can also induce a significant reduction in the anxiety and depression-like effect induced by PND9 LPS administration. CONCLUSION: Our results demonstrated that melatonin possesses potent protective effect against the depression and anxiety induced by LPS. The underlying effect of melatonin is probably due to the reduction of nitric oxide toxic effect and lipid peroxidation in addition to its anti-inflammatory effect.

Three novel CYP11B1 mutations in congenital adrenal hyperplasia due to steroid 11Beta-hydroxylase deficiency in a moroccan population.

BACKGROUND/AIMS: Steroid 11beta-hydroxylase deficiency (11OHD), the second cause of congenital adrenal hyperplasia (CAH), accounts only for 5% of all CAH. To date, only 51 different mutations have been reported with poor clinical and biological data. Most of them could be considered as private mutations except one, p.R448H, identified especially in Moroccan Jews but also in Caucasian patients. As two other CYP11B1 mutations have a high incidence in Tunisian patients, we report from another Maghreb population the clinical, follow-up and molecular genetics of 5 Moroccan patients with classical 11OHD. METHODS: Patients belonging to 3 families were recruited on clinical data. The diagnosis was confirmed by 11-deoxycortisol determination. Sequencing of the CYP11B1 gene and molecular modeling were performed. RESULTS: Clinical, hormonal and follow-up data were consistent with a severe form of 11OHD. Gender reassignment and evolution of hypertension were discussed. Three novel mutations, p.Ala259Asp, p.Gly446Val and IVS5+2T>G were identified. As each patient was homozygous for one mutation, we could deduce from their phenotype and our modeling studies that the p.Gly446Val mutation was more severe than p.Ala259Asp. CONCLUSION: This study shows a good correlation between phenotype and genotype. Each CYP11B1 mutation is new and private, contrasting with the high incidence of two Tunisian mutations.

Preventive effects of flaxseed and sesame oil on bone loss in ovariectomized rats.

A study was designed to examine the effects of dietary flaxseed oil (FO) and sesame oil (SO) which are rich successively in n-3 and (n-9 and n-6) on biochemical parameters and histological status of bone. Sixty-four 90-day-old female wistar rats were randomly assigned to 6 groups: sham-operated rat (sham)+ control diets, ovariectomized rat (OVX) + control diets, OVX + 7% FO, OVX + 7% SO, OVX + 10% FO, OVX + 10% SO. After 4 weeks of treatments, rats were euthanized; blood and tissues were collected for analyses. Markers of bone formation which is alkaline phosphatase activity and markers of bone resorption which is tartrate resistant acid phosphatase activity were measured. Present results showed that OVX increased significantly ALP and TRAP activity and the examination of bone tissue showed disruptive and lytic bone trabeculae. Animals fed 10% FO and 10% SO of fat reduced these parameters and improved bone microarchitecture. Whereas, there was no improvement in biochemical and histological states in OVX rats that received 7% of PUFAs successively provided from FO and SO diets. In conclusion, our results are encouraging because they suggest that PUFAs intake may help to prevent osteoporosis associated with estrogens deficiency. However, further studies are needed to determine the mechanism by which a diet rich in n-3 or lignans modulate bone tissue.

Effects of amphetamine and phenylethylamine on catecholamine release in the glomerular layer of the rat olfactory bulb.

In the present work, we have shown electrochemically that in the rat olfactory bulb (OB), extracellular dopamine (DA) was highest in the glomerular layer (GL), whereas extracellular noradrenaline (NA) appeared to be more uniformly distributed across layers. The GL catecholamine (CA) responses to amphetamine (AMPH) and phenylethylamine (PEA) were also characterized electrochemically using an in vivo model. Results of this investigation show that at a lower dose (1 mg/kg), PEA had no effect on CA release. In contrast, at a higher dose (10 mg/kg), it produced similar increases in either extracellular DA (17.5 +/- 7%) or extracellular NA (14 +/- 3%), and DA exhibited dose-independent increases to AMPH (93 +/- 8%: 1 mg/kg vs. 97 +/- 6%: 10 mg/kg) whereas NA exhibited dose-dependent increases to AMPH (24.5 +/- 6%: 1 mg/kg vs. 39 +/- 7%: 10 mg/kg). These data indicate that (i) PEA may increase CA release but less efficiently than AMPH. (ii) AMPH is more efficient on the DAergic than on the NAergic system since AMPH-induced DA release exceeded 2-4 times the AMPH-induced NA release.

Parathyroid hormone and glucagon compete for binding to low affinity sites on human skin fibroblasts.

We have studied the binding sites for parathyroid hormone (PTH) present on normal human fibroblasts by studying these receptors with respect to (1) affinity and specificity towards various peptide hormones including human PTH(1-34) and porcine glucagon(1-29); (2) ability to mediate stimulation of cAMP production in response to these hormones; and (3) molecular size. Binding assays using 125I-labelled human PTH(1-34) and 125I-labelled porcine glucagon(1-29), and hormone stimulations of cAMP production were performed on confluent fibroblasts grown in 24-well dishes (passage 4-10). The molecular sizes of the binding sites for PTH and glucagon were assessed after cross-linking to the corresponding 125I-labelled ligand using the heterobifunctional reagent 1,4-difluoro-2,5-dinitrobenzene (DFDNB), by sodium dodecyl sulphate gel electrophoresis and autoradiography. The results demonstrate: (1) Biologically active PTH and glucagon, but not other peptide hormones tested, are equipotent competitors for binding on human fibroblasts to sites which have a relatively low affinity for these ligands (Kd approximately 0.8-2.4 x 10(-7) M); these sites have an apparent molecular weight of 95 kDa and are not linked to stimulation of cAMP production by PTH. (2) A distinct class of receptors for PTH with an apparent molecular weight of 60 kDa and which probably are linked to stimulation of cAMP production by PTH is also expressed by these cells; glucagon cannot compete with PTH for binding to these sites, and does not interfere with the stimulation of cAMP production by PTH. (3) Glucagon does not stimulate cAMP production in human fibroblasts.(ABSTRACT TRUNCATED AT 250 WORDS)

The resistance to parathyroid hormone of fibroblasts from some patients with type Ib pseudohypoparathyroidism is reversible with dexamethasone.

Skin fibroblasts from some patients with pseudohypoparathyroidism type Ib (PHP-Ib) are resistant to PTH. To characterize the defect producing PTH resistance in these cells and determine whether the abnormality is potentially reversible, we evaluated the ability of fibroblasts from patients with PHP-Ib to produce cAMP in response to PTH both before and after exposure to dexamethasone, an agent known to increase PTH responsiveness in other cell types. Before dexamethasone treatment, fibroblasts from five of eight patients with PTH-Ib produced reduced amounts of cAMP in response to PTH (but not prostaglandin E1 and forskolin) compared to that of control cells (6.3 +/- 1.0 and 37.3 +/- 6.3 pmol cAMP/100 micrograms protein, respectively). Whereas dexamethasone pretreatment had no effect on cAMP production by control or PTH-responsive PHP-Ib fibroblasts, it resulted in a dose-dependent increase in PTH-induced cAMP production by PTH-resistant fibroblasts to normal levels in four of five cases. Studies evaluating the binding of radiolabeled PTH did not permit quantification of the small number of high affinity PTH receptors present on these cells. We conclude that PTH resistance in PHP-Ib patients with PTH-resistant fibroblasts results from an abnormality in the expression of or coupling to cyclase of high affinity PTH-receptor complexes. Because it is expressed in only some tissues and is reversible, the defect could be regulatory in nature.