Effect of α-lipoic acid on spatial memory and structural integrity of developing hippocampal neurons in rats subjected to sodium arsenite exposure.

BACKGROUND: Exposure to arsenic has been reported to affect the nervous system in a number of ways. Various epidemiological studies suggest cognitive impairment in subjects following exposure to environmental arsenic. The goal of the present study was to determine if supplementation of exogenous α-lipoic acid (ALA) could ameliorate sodium arsenite (NaAsO2) induced adverse effects on learning and memory and synaptic connectivity in rat hippocampus. METHODS: Accordingly, NaAsO2 alone (1.5/2.0 mg/kg bw) or NaAsO2 along with ALA (70 mg/kg bw) was administered by intraperitoneal (i.p.) route from postnatal day (PND) 4-17 to Wistar rat pups (experimental groups) and the Control groups received either distilled water or no treatment at all. After carrying out Elevated Plus Maze (EPM) and Morris Water Maze (MWM) test, the fresh brain tissues were collected on PND 18 and processed for Golgi Cox staining. RESULTS: Observations of MWM test revealed impaired learning and memory in iAs alone treated animals as against those co-exposed to iAs and ALA. In Golgi stained hippocampal sections of iAs alone treated animals, decreased dendritic arborization and reduced number of spines in pyramidal neurons (CA1) and granule cells (DG) was observed whereas neuronal morphology was preserved in the controls and ALA supplemented groups CONCLUSIONS: These observations are suggestive of beneficial effects of ALA on iAs induced effects on learning and memory as well as on hippocampal neuronal morphology.

Evaluation of osteologic parameters of jugular foramen and its significance with respect to expanded endoscopic endonasal approach

The jugular foramen (JF) is a large irregular hiatus, lies at the posterior end of the petro-occipital suture, posterior to the opening of carotid canal (CC) and it transmits major neurovascular structures. Tumors are the most common pathology involving structures present in JF. In the current scenario, lesions of structures present in JF progressing towards midline are suitably removed by expanded endoscopic endonasal approach (EEEA). In lieu of EEEA, we studied new parameters in relation to JF. The study was done on 50 human dry skulls with the help of sliding Vernier caliper and statistical analysis was done using SPSS software. Morphological study on the presence of dome, septa and relation of CC to JF was done. Morphometric parameters of JF and its distance from vomer, medial pterygoid plate (MPP), lateral pterygoid plate (LPP) and CC were studied. We also determined the distance from lateral and medial end of CC to the midsagittal plane (MSP). The dome of the jugular fossa (JFo) was seen in 42% skulls, each bilaterally and unilaterally. Complete and incomplete septa in JF were seen in 4% & 16% bilaterally and 8% & 18% unilaterally respectively. In the majority of the skulls, position of CC was anterior to JF and anteromedial was the next common position seen. Length & width of JF, depth of JFo, distance of JF from vomer, MPP, LPP & CC and the distance of CC to the MSP were more on the right side. This study may help neurosurgeons & ENT surgeons while approaching lesions around JF by EEEA

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Morphological and Morphometric Analysis of Hypoglossal Canal in North Indian Dry Skulls and It's Significance in Cranial Base Surgeries.

INTRODUCTION: Hypoglossal Canal (HC) is a paired bony passage which is situated above the Occipital Condyle (OC) and transmits hypoglossal nerve and blood vessels. Studies on the osteotic variations of HC has been a field of considerable interest to research workers especially because of its clinical, radiological and surgical significance. AIM: The aim of the present study was to analyze the morphological and morphometric features of HC and its topographical relationship with OC. MATERIALS AND METHODS: The present study was done on 50 human dry skulls. The HC was looked for presence of spur and septa along with its location in the canal and were classified into different types accordingly. The distance of extracranial and intracranial openings of HC from the posterior end of OC was measured by Sliding Vernier caliper. Angle of inclination of HC with the midsagittal plane was measured with the help of goniometer. RESULTS: In the present study, we observed osteotic variations in the HC in 52% skulls. The spur (Type 2) was seen in 28% and incomplete septa (Type 3) was noted in 26% skulls. In some cases, spur and septa were seen in different locations of same HC. However, complete septa (Type 4) were not observed in our study. Spur and septa, both were present more frequently on the left side. The external and internal distance of HC from posterior end of OC was more on the left side in comparison to the right side. The anterior angle of HC to the midsagittal plane is less in comparison to posterior angle in case of double internal opening of HC. CONCLUSION: The present study regarding morphologic and morphometric analysis of HC and its relation to the OC will provide important information in North Indian population. It will enable effective and reliable surgical intervention in the area of HC and craniovertebral junction leading to better postoperative outcome.

The anatomical perspective of human occipital condyle in relation to the hypoglossal canal, condylar canal, and jugular foramen and its surgical significance.

BACKGROUND: The transcondylar approach (TCA) has gained importance in recent era which enables shorter and direct route to access the lesions ventral to the brainstem. The important step in this approach is resection of the occipital condyle (OC). The detailed knowledge of bony anatomy of OC and its relation to the hypoglossal canal (HC), condylar canal (CC), and jugular foramen (JF) is very important to avoid any iatrogenic injury during craniovertebral surgeries. The aim of the present study is to conduct a morphometric and morphological study and note the variations of the OC and the structures surrounding it in North Indian population. MATERIALS AND METHODS: The study was carried out on 100 OC. Morphometric measurements of OC and the distances of HC and JF from the posterior end of OC were noted. In addition, the extent of the HC and JF in relation to OC, presence or absence of CC, shape of the OC, and its articular facet were also noted. RESULTS: The incidence of short OC was seen in 13% skulls. The most common shape of OC was oval or rhomboid. Even though the articular facet was convex in majority of skulls but flat (10%) and concave (1%) were also observed. The external and internal distance of HC from the posterior end of OC was13.83 mm and 10.66 mm on the right side and 15.02 mm and 11.89 mm on the left side. The OC was related in its middle 1/3 to the HC in 15% skulls and to the whole extent of JF in 3% skulls. Thirty-four percent skulls displayed the septa in the HC. The CC was present bilaterally in 38% skulls and unilaterally in 40% skulls. CONCLUSION: The OC and related structures such as HC, CC, and JF are likely to have variations in respect to morphometry and morphology. This study may prove helpful to neurosurgeons operating in this field, especially during TCA where neurovascular structures emerging from these canals and foramen are more vulnerable to injury.

Alpha lipoic acid (ALA) modulates expression of apoptosis associated proteins in hippocampus of rats exposed during postnatal period to sodium arsenite (NaAsO2).

The present study focused on the role of exogenous alpha lipoic acid (ALA) in amelioration of inorganic arsenic (iAs) induced effects on apoptosis and apoptosis associated proteins in developing rat hippocampus. NaAsO2 (1.5/2.0 mg/kg bw) alone or along with ALA (70 mg/kg bw) was administered to rat pups (experimental groups) by intraperitoneal (i.p.) route from postnatal day (PND) 4-15. Controls received no treatment/distilled water/ALA. On PND 16, the animals were perfusion fixed and the brains were processed for paraffin embedding (CV and TUNEL staining) and cryopreservation (immunohistochemistry). The fresh brain tissue was used for Western blotting. Significant increase was observed in TUNEL positive cells and Bax (pro-apoptotic protein) expression in hippocampal sub-regions of iAs alone treated groups, whereas Bcl-2 expression was intensified in animals receiving ALA with iAs. Densitometric analysis (Western blots) revealed optimal restoration of Bax and Bcl-2 ratio in animals receiving ALA with iAs, thereby suggesting the protective role of ALA in iAs induced developmental neurotoxicity.

Novel high-molecular weight fucosylated milk oligosaccharides identified in dairy streams.

Oligosaccharides are the third largest component in human milk. This abundance is remarkable because oligosaccharides are not digestible by the newborn, and yet they have been conserved and amplified during evolution. In addition to encouraging the growth of a protective microbiota dominated by bifidobacteria, oligosaccharides have anti-infective activity, preventing pathogens from binding to intestinal cells. Although it would be advantageous adding these valuable molecules to infant milk formula, the technologies to reproduce the variety and complexity of human milk oligosaccharides by enzymatic/organic synthesis are not yet mature. Consequently, there is an enormous interest in alternative sources of these valuable oligosaccharides. Recent research has demonstrated that bovine milk and whey permeate also contain oligosaccharides. Thus, a thorough characterization of oligosaccharides in bovine dairy streams is an important step towards fully assessing their specific functionalities. In this study, bovine milk oligosaccharides (BMOs) were concentrated by membrane filtration from a readily available dairy stream called "mother liquor", and analyzed by high accuracy MALDI FT-ICR mass spectrometry. The combination of HPLC and accurate mass spectrometry allowed the identification of ideal processing conditions leading to the production of Kg amount of BMO enriched powders. Among the BMOs identified, 18 have high-molecular weight and corresponded in size to the most abundant oligosaccharides present in human milk. Notably 6 oligosaccharides contained fucose, a sugar monomer that is highly abundant in human milk, but is rarely observed in bovine milk. This work shows that dairy streams represent a potential source of complex milk oligosaccharides for commercial development of unique dairy ingredients in functional foods that reproduce the benefits of human milk.

Preliminary morphological and immunohistochemical changes in rat hippocampus following postnatal exposure to sodium arsenite.

The effects of arsenic exposure during rapid brain growth period (RBGP) (postnatal period 4-11) on pyramidal neurons of cornu ammonis (specifically CA1 and CA3 regions) and granule cells of dentate gyrus (DG) of rat hippocampus were studied. Wistar rat pups, subdivided into the control (group I) and the experimental groups (group II, III, and IV), received distilled water and sodium arsenite (aqueous solution of 1.0, 1.5, and 2.0 mg/kg body weight, respectively) by intraperitoneal (i.p.) route. On postnatal day (PND) 12, the animals were sacrificed and brain tissue obtained. Paraffin sections (8 µm thick) stained with Cresyl Violet (CV) were observed for morphological and morphometric parameters. Arsenic induced programmed cell death (apoptosis) was studied using Terminal deoxyribonucleotidyl transferase mediated dUTP biotin Nick End Labeling (TUNEL) technique on the paraffin sections. Microscopy revealed decreased number and isolation of pyramidal neurons in superficial layers, misalignments of pyramidal cells in stratum pyramidale (SP) of CA1 and CA3 in experimental group III and IV, and presence of polymorphic cells in subgranular zone of ectal limb of dentate gyrus (suggestive of arsenic induced proliferation and migration of granule cells in the dentate gyrus). Morphometric assessments quantified and confirmed the microscopic findings. The mean nuclear area of pyramidal cells was increased and cell density was decreased in the CA1, CA3, and DG of experimental groups in comparison to the control group. Increase in the TUNEL positive cells in DG was observed in the experimental group IV, suggestive of increased apoptosis. These observations confirm vulnerability of pyramidal (CA1, CA3) and granule cells (DG) of hippocampus during RBGP.

Cardioprotective effect of root extract of Picrorhiza kurroa (Royle Ex Benth) against isoproterenol-induced cardiotoxicity in rats.

Normal rats pre-treated with P. kurroa (200 mg/kg) alone did not showed significant change, however, isoproterenol (ISP) administration resulted in hemodynamic and left ventricular dysfunction, oxidative stress, and lipid peroxidation. Such cardiac dysfunction was significantly prevented by P. kurroa root extract pre-treatment. Pre-treatment significantly attenuated the ISP-induced oxidative stress by restoring myocardial superoxide dismutase, catalase, and glutathione peroxidase enzymes except reduced glutathione content. P. kurroa pre-treatment markedly attenuated the ISP-induced rise in lipid peroxidation, thereby prevented leakage of myocyte creatine kinase-MB and lactate dehydrogenase enzymes. The results suggest that P. kurroa root extract possesses significant cardioprotective effect, which may be attributed to its antioxidant, anti-peroxidative, and myocardial preservative properties.

Postnatal Exposure to Sodium Arsenite (NaAsO(2)) Induces Long Lasting Effects in Rat Testes.

OBJECTIVE: The present study was undertaken to investigate the effects of early postnatal exposure to sodium arsenite (NaAsO(2)) on rat testis. MATERIALS AND METHODS: Wistar rat pups were administered aqueous solution of NaAsO(2,) 1.5 mg/kg body weight (bw) (experimental) and distilled water (control), respectively, by intraperitoneal route (i.p.) from postnatal day (PND) 1 to 14. Testes were collected after 1, 7 and 36 days (at PND 15, 21 and 50) after the treatment period (PND1-14) from the animals and immersion fixed in Bouin's fluid followed by paraffin embedding. Seven micrometer thick serial sections were cut and stained with hematoxylin and eosin for light microscopic observations. At PND 50, morphological features of sperms and their counting was carried out besides processing the perfusion-fixed testes for electron microscopy (EM). RESULTS AND CONCLUSIONS: The observations revealed an altered morphology of the seminiferous tubules (ST) along with degeneration and dissociation of spermatogenic cells in the experimental animals at PND 15, 21 and 50. Also, increased number of sperms with abnormal morphology and decreased sperm count was noted in the experimental animals. These features together with electron microscopic observations of abnormal mitochondria and apoptotic nuclei of spermatogonia and spermatocytes could be indicative of long-lasting adverse effects on the rat testis induced by exposure to As during early postnatal period.

Are the neuroprotective effects of estradiol and physical exercise comparable during ageing in female rats?

Ageing of the brain is accompanied by variable degrees of cognitive decline. Estrogens have profound effects on brain ageing by exerting neurotrophic and neuroprotective types of action. Furthermore, exercise has also been claimed to play a role in the non-pharmacological prevention of psycho-neuronal decline with ageing. In the present study the question was asked whether chronic physical exercise might substitute the action of estrogens in aged rats. We compared the effects of 17ß-estradiol (E2) treatment and long-term moderate physical exercise in ageing (15 months, early stage of ageing) and old (27 months) female rats, on cognitive functions and the relevant intracellular molecular signaling pathways in the hippocampus. Results showed that both treatments improved attention and memory functions of the 15 months old rats. Like E2, physical training enhanced the level of brain derived nerve growth factor and the activation of PKA/Akt/CREB and MAPK/CREB pathways. The treatments also enhanced the levels of synaptic molecules synaptophysin and synapsin I, which could explain the improved cognitive functions. In the 27 months old rats the behavioral and molecular effects of E2 were indistinguishable from those found in the 15 months old animals but the effects of physical exercise in most of the measures proved to be practically ineffective. It is concluded that the effectiveness of regular and moderate intensity physical exercise is age-dependent while the action of E2 treatment is comparable between the ageing and old female rats on maintaining cognition and its underlying molecular mechanisms.

Preliminary morphological and biochemical changes in rat liver following postnatal exposure to sodium arsenite.

The effects of sodium arsenite exposure on the hepatic maturation period of cellular and functional reorganization in developing rat livers were evaluated. Animals received intraperitoneal injections of sodium arsenite (1.5 mg/kg body weight) or distilled water on days 9 to 28 after birth. On day 29, the animals were sacrificed either by cervical dislocation or by perfusion fixation. The perfusion fixed liver tissue was processed for paraffin embedding, sectioning and hematoxylin and eosin staining. The fresh liver tissue was processed for cryo-sectioning followed by Sudan Black B staining and for biochemical estimation of reduced glutathione. Microscopic observation revealed comparable preserved hepatic lobular patterns and distributions of uninucleate and binucleate hepatocytes in the control and the experimental groups. The mean nuclear area and diameter of the hepatocytes was increased in the experimental group. Lipid droplet distribution pattern in Sudan Black B stained sections revealed higher staining intensity towards the centrilobular area in both groups. Semiquantitative estimation of staining intensity showed lower mean gray values in zone 3 than in zones 2 and 1 (suggestive of the setting in of the adult pattern) in both groups. The reduced glutathione levels in the liver tissue and the altered nuclear size of the hepatocytes in the experimental group suggested the impairment of morphological and biochemical processes induced by arsenic exposure during the postnatal period.

Protective role of exogenous α-lipoic acid (ALA) on hippocampal antioxidant status and memory function in rat pups exposed to sodium arsenite during the early post-natal period.

The present work focussed on the effect of exogenous α-lipoic acid (ALA) administration on retention memory and oxidative stress markers in the hippocampus subsequent to early post-natal exposure of rat pups to sodium arsenite (NaAsO(2)). Wistar rat pups were divided into the control groups receiving either no treatment (Ia) or distilled water by intraperitoneal route (i.p.) (Ib) and the experimental groups receiving either NaAsO(2) alone (1.5 and 2.0 mg/kg body wt.) (IIa, IIb) or NaAsO(2) (1.5 and 2.0 mg/kg body wt.) followed by ALA (70 mg/kg body wt.) (IIIa, IIIb) (i.p.) from post-natal day (PND) 4-15. The initial and retention transfer latency (ITL and RTL) was determined on PND 14 and 15 using elevated plus maze. The animals were sacrificed by cervical decapitation (PND 16) and the brains were obtained. The dissected out hippocampus was processed for estimation of oxidative stress markers, glutathione (GSH), and superoxide dismutase (SOD). NaAsO(2) exposure resulted in longer RTL in animal groups IIa and IIb, thereby suggestive of arsenic-induced impairment in retention memory. RTL was significantly shorter in animal groups (IIIa, IIIb) receiving ALA following NaAsO(2), thereby suggestive of improvement in retention memory. GSH and SOD levels were significantly decreased in animals receiving NaAsO(2) alone as against group Ib and administration of ALA following NaAsO(2) increased the levels of hippocampal GSH and SOD. These observations are suggestive of the role of exogenous ALA in ameliorating the adverse effects induced by NaAsO(2) exposure of rat pups on retention memory and oxidative stress markers.

Development of biosensor-based assays to identify anti-infective oligosaccharides.

It is now well accepted that milk oligosaccharides can have a direct inhibitory effect on pathogenic microorganisms by interfering with their adhesion to human cells. Many free oligosaccharides from milk are considered to be soluble receptor analogs of epithelial cell surface carbohydrates and, thus, function as receptor decoys to which pathogens can bind instead of the host. In reality, there are few rapid methods to screen for such oligosaccharides, and much of the research in this area has centered on using human cell line models of infection that are time-consuming. Therefore, a quick and sensitive method is required for detecting the binding of microorganisms to milk oligosaccharides. Our study describes a number of biosensor-based methods to achieve these aims. Our approach involved the exposure of whole bacterial cells to the well-characterized human milk oligosaccharide, 2'-fucosyllactose, immobilized to a pretreated gold chip surface. The technique was validated by screening a range of pathogenic bacteria, including Campylobacter jejuni, to which 2'-fucosyllactose is known to bind. Where binding was detected, its specificity was confirmed by preincubation studies using unlabeled 2'-fucosyllactose. The techniques described represent a quick, cost-effective, and highly reproducible detection method for identifying anti-infective oligosaccharides.

The food glycome: a source of protection against pathogen colonization in the gastrointestinal tract.

Trillions of microbes inhabit the gastrointestinal tract of humans with significant differences in the composition and distribution of intestinal flora along its length. Normally there is a symbiotic relationship between the intestinal microflora and the host, with mutual advantages for both partners. When this relationship is altered, commensal bacteria can rapidly shift toward pathogenicity resulting in the onset and progression of gastrointestinal infection. Pathogen adhesion and colonization is often a prelude to infection, and intervention at this early stage can help prevent disease. Bacteria have evolved a multitude of adhesion mechanisms commonly targeting surface carbohydrate structures of the host. Here, we review the ability of various dietary carbohydrates to prevent adhesion of pathogens to host cells. Given their significance in disease, and their ability to cause chronic infection, we have focussed on 3 model pathogens, Helicobacter pylori, Campylobacter jejuni and Clostridium difficile, and dietary carbohydrates which can inhibit their adhesion. The discovery of novel anti-adhesive dietary carbohydrates, once developed as nutraceutical ingredients, may serve as a novel method for preventing infectious diseases in the human gastrointestinal tract. Anti-adhesive carbohydrates used in this context are not bactericidal. Therefore, the spread of pathogens with resistance to antibiotics is less likely to occur.

Neuroprotective effects of estrogen treatment on ischemia-induced behavioural deficits in ovariectomized gerbils at different ages.

Although much is known about the protective effect of acute estrogen therapy in cerebral ischemia, relatively little is known about its effect on functional outcome at different ages. The impact of age is, however, important on the efficacy of steroids in the central nervous system. We investigated whether a single dose of estradiol pre-treatment would be neuroprotective in young (4 months), middle-aged (9 months) and old (18 months) female gerbils following 10min global brain ischemia. Apoptotic and necrotic cells were labelled and quantified in the affected hippocampus; exploratory activity, attention and memory functions were tested using open field, spontaneous alternation, novel object recognition and hole-board test. Age effect and treatment effect were analysed. High single dose (4mg/kg b.w.) of estradiol pre-treatment exposed a marked neuroprotective effect against hippocampal cell loss in all age groups. In behavioural tests, however, age-related differences could be observed. In middle-aged and old animals the worsening in memory function following ischemia was more prominent compared to that in the young ones. In the Y-maze and the novel object recognition tests the middle-aged, in the hole-board test (investigating working memory and total time) the old gerbils had the worst functional outcome. Only reference memory in hole-board test did not change by age. Estrogen improved memory performances in all the tests at every age. We can conclude that age of experimental animals is a factor worsening the outcome following brain ischemia. A single-dose estrogen therapy prevents the lesion-induced behavioural dysfunctions and the hippocampal cell loss.

Effect of Commiphora mukul extract on cardiac dysfunction and ventricular function in isoproterenol-induced myocardial infarction.

In present study, hydroalcoholic extract of C. mukul significantly improved the cardiac function and prevented myocardial ischemic impairment manifested in the form of increased heart rate, decreased arterial pressure, increased left ventricular end diastolic pressure, and altered myocardial contractility indices. C. mukul treatment additionally also produced a significant increase in lactate dehydrogenase levels and prevented decline of protein content in heart. C. mukul preserved the structural integrity of myocardium. Reduced leakage of myocyte enzyme lactate dehydrogenase and maintenance of structural integrity of myocardium along with favorable modulation of cardiac function and improved cardiac performance indicate the salvage of myocardium with C. mukul treatment. Guggulsterones which are considered to be responsible for most of the therapeutic properties of C. mukul may underlie the observed cardioprotective effect of C. mukul against cardiac dysfunction in isoproterenol-induced ischemic rats.

Long-term administration of estrogen or tamoxifen to ovariectomized rats affords neuroprotection to hippocampal neurons by modulating the expression of Bcl-2 and Bax.

Recently we reported that chronic treatment with 17beta-estradiol (E2) or tamoxifen (TAM) regulates the ovariectomy-induced downregulation of the key molecules linked to hippocampal synaptic plasticity and signal transduction pathway. We now report modulation of the antiapoptotic (Bcl-2) and proapoptotic (Bax) proteins in the hippocampus of both the ovariectomized (OVX) rats as well as those given E2 or TAM subcutaneously as a daily dose for four weeks post-ovariectomy. Forty bilaterally OVX animals were divided into four groups of 10 each, namely i) OVX+E2 (0.1 mg/kg body weight), ii) OVX+TAM (0.05 mg/kg body weight), iii) OVX+vehicle (0.1 ml of sesame oil) and iv) OVX controls. An additional group of 10 animals constituted the ovary intact controls. Following culmination of treatment regimen, brain tissues of five animals from each group were processed for immunohistochemical staining of Bcl-2 and Bax on perfusion fixed cryo-sections. The remaining animals in each group were utilized for protein and Western blot analyses using unfixed hippocampal tissue. The results revealed that chronic administration of both E2 and TAM prevented the ovariectomy-induced downregulation of Bcl-2 and upregulation of Bax expression while restoring the Bcl-2/Bax ratio as observed in the ovary intact rats. Furthermore, TUNEL assay demonstrated a decline in the percentage of TUNEL positive cells in E2 or TAM treated groups. Confocal microscope studies of ERalpha and the apoptotic markers revealed that these two proteins co-reside in the same ERalpha positive hippocampal neurons. Thus, long-term E2 or TAM therapy modulates the apoptotic proteins and affords neuroprotection to the hippocampal neurons. Furthermore the estrogen-like effects of TAM point towards its potential as a beneficial therapeutic agent for neurodegenerative disorders, particularly in the postmenopausal women.

Preliminary morphological and morphometric study of rat cerebellum following sodium arsenite exposure during rapid brain growth (RBG) period.

The effects of arsenic exposure during rapid brain growth (RBG) period were studied in rat brains with emphasis on the Purkinje cells of the cerebellum. The RBG period in rats extends from postnatal day 4 (PND 4) to postnatal day 10 (PND 10) and is reported to be highly vulnerable to environmental insults. Mother reared Wistar rat pups were administered intraperitoneal injections (i.p.) of sodium arsenite (aqueous solution) in doses of 1.0, 1.5 and 2.0mg/kg body weight (bw) to groups II, III and IV (n=6 animals/group) from PND 4 to 10 (sub acute). Control animals (group I) received distilled water by the same route. On PND 11, the animals were perfusion fixed with 4% paraformaldehyde in 0.1M phosphate buffer (PB) with pH 7.4. The cerebellum obtained from these animals was post-fixed and processed for paraffin embedding. Besides studying the morphological characteristics of Purkinje cells in cresyl violet (CV) stained paraffin sections (10 microm), morphometric analysis of Purkinje cells was carried out using Image Analysis System (Image Proplus software version 4.5) attached to Nikon Microphot-FX microscope. The results showed that on PND 11, the Purkinje cells were arranged in multiple layers extending from Purkinje cell layer (PL) to outer part of granule cell layer (GL) in experimental animals (contrary to monolayer arrangement within PL in control animals). Also, delayed maturation (well defined apical cytoplasmic cones and intense basal basophilia) was evident in Purkinje cells of experimental animals on PND 11. The mean Purkinje cell nuclear area was significantly increased in the arsenic treated animals compared to the control animals. The observations of the present study (faulty migration, delayed maturation and alteration in nuclear area measurements of Purkinje cells subsequent to arsenic exposure) thus provided the morphological evidence of structural alterations subsequent to arsenite induced developmental neurotoxicity which could be presumed to be the underlying basis for some of the functional deficits encountered in the later period of life.

Chronic exposure to estrogen and tamoxifen regulates synaptophysin and phosphorylated cAMP response element-binding (CREB) protein expression in CA1 of ovariectomized rat hippocampus.

We report here the in vivo effects of estrogen (E2) on modulation of synaptic plasticity and the agonistic (estrogen-like) role of selective estrogen receptor modulator (SERM), tamoxifen (TAM) in the CA1 of the rat hippocampus. Effects on synaptophysin (SYP), a presynaptic vesicular protein, and phosphorylated cyclic AMP responsive element-binding (p-CREB) protein, a signal transduction pathway molecule, were studied using the ovariectomized (OVX) experimental rat model. Bilateral ovariectomy was performed on 40 rats and these were divided into 4 groups based on the treatment they received (at 2 weeks post-ovariectomy, a subcutaneous injection daily for 4 weeks) viz., OVX+E2 (0.1 mg/kg body weight), OVX+TAM (0.05 mg/kg body weight), OVX+vehicle and one group served as OVX control. An additional 10 animals served as the ovary intact control group. At the end of the treatment schedule, five animals/group were used for immunohistochemical staining of SYP and p-CREB using specific antibodies with peroxidase anti-peroxidase technique on paraformaldehyde-fixed cryostat sections. Protein estimation and Western blot analysis coupled with densitometric analysis (using gel-documentation system and image analysis software) were performed on unfixed hippocampus collected from rest of the five animals/group. Serum estradiol levels were estimated with radioimmunoassay prior to sacrifice. The results revealed that ovariectomy reduced SYP and p-CREB expression whereas E2 or TAM administration resulted in their upregulation. Serum estradiol levels of E2 administered animals were comparable with the ovary intact group whereas those of TAM administered group persisted in the range of OVX controls. To conclude, long-term estrogen therapy modulates the synaptic plasticity of hippocampal neurons and presumably, the agonist biocharacter of TAM as observed in the present investigations, may in the long run have a potential in the treatment and prevention of various estrogen-related disorders.

Effect of mifepristone on steroid receptor expression and biotransformation of oestrogen and progesterone in rat uterus and deciduoma.

BACKGROUND: [corrected] Mifepristone is a synthetic antiprogestin which terminates early pregnancy. Since it interferes with the progesterone maintained decidua, we compared the effect of mifepristone on oestrogen and progesterone receptors, and on the biotransformation of these hormones in normal and deciduous uterus. METHODS: Ovariectomized rats were treated with an oestrogen-progesterone hormone regimen and deciduoma was induced by trauma in one horn of the rat uterus while the other served as a control under an identical hormonal milieu. Hormone receptor and biotransformation studies were done using radiolabelled oestradiol and progesterone with high specific activity. RESULTS: The artificially formed decidual tissue was comparable with that of early pregnancy. Mifepristone replenished oestrogen and progesterone receptors which were suppressed by progesterone in both the normal and decidualized uterine horns. Inhibition of oestrogen receptors by progesterone correlated with decreased oestradiol levels at the site of action. Metabolism of progesterone to less potent compounds was promoted by mifepristone. The enzymatic activities of 17beta-hydroxysteroid dehydrogenase (which metabolizes oestradiol), and 20alpha-hydroxysteroid dehydrogenase and 5alpha-reductase (which metabolize progesterone) were altered by mifepristone. CONCLUSION: The effect of mifepristone in varying the hormone receptor population and the availability of different levels of active metabolites of ovarian hormones have an Important role in the antiprogestin action of mifepristone.