Astrogliosis and associated CSPG upregulation adversely affect dendritogenesis, spinogenesis and synaptic activity in the cerebellum of a double-hit rat model of protein malnutrition (PMN) and lipopolysaccharide (LPS) induced bacterial infection

The extracellular matrix (ECM) plays a vital role in growth, guidance and survival of neurons in the central nervous system (CNS). The chondroitin sulphate proteoglycans (CSPGs) are a type of ECM proteins that are crucial for CNS homeostasis. The major goal of this study was to uncover the effects of astroglial activation and associated intensified expression of CSPGs on dendritogenesis, spinogenesis as well as on synaptic activity in cerebellum following protein malnutrition (PMN) and lipopolysaccharide (LPS) induced bacterial infection. Female Wistar albino rats (3 months old) were switched to control (20% protein) or low protein (LP, 8% protein) diet for 15 days followed by breeding. A set of pups born to control/LP mothers and maintained on respective diets throughout the experimental period constituted the control and LP groups, while a separate set of both control and LP group pups exposed to bacterial infection by a single intraperitoneal injection of LPS (0.3 mg/ kg body weight) on postnatal day-9 (P-9) constituted control+LPS and LP+LPS groups respectively. The consequences of astrogliosis induced CSPG upregulation on cerebellar cytoarchitecture and synaptic activity were studied using standard immunohistochemical and histological tools on P-21 and 6 months of age. The results revealed reactive astrogliosis and associated CSPG upregulation in a double-hit model of PMN and LPS induced bacterial infection resulted in disrupted dendritogenesis, reduced postsynaptic density protein (PSD-95) levels and a deleterious impact on normal spine growth. Such alterations frequently have the potential to cause synaptic dysregulation and inhibition of plasticity both during development as well as adulthood. At the light of our results, we can envision that upregulation of CSPGs in PMN and LPS co-challenged individuals might emerge as an important modulator of brain circuitry and a major causative factor for many neurological disorders.

Maternal Spirulina supplementation during pregnancy and lactation partially prevents oxidative stress, glial activation and neuronal damage in protein malnourished F1 progeny

Protein malnutrition (PMN) is a global health issue but most prevalent in Africa and Asia. It exerts detrimental effect on structural and physiological aspects of hippocampal circuitry. Despite accumulating evidence for PMN induced changes in nervous system, relatively very little is known about how maternal nutritional supplementation during malnutrition affects glial cells and neurons. Herein, we aimed to investigate the effects of maternal Spirulina supplementation against PMN induced oxidative stress, reactive gliosis and neuronal damage in hippocampus of F1 progeny. Three months old healthy Sprague Dawley females (n = 24) were shifted to normoprotein (NC; 20% protein) and low protein (LP; 8% protein) diets 15 days before conception. The NC and LP group females were subdivided into two groups according to Spirulina supplementation (400 mg/kg/b.wt. orally throughout gestation and lactation period): normal control with Spirulina (NC SPI) and low protein with Spirulina supplemented group (LP SPI). F1 progeny born were used in present study. Thus, building on earlier results of ameliorated neurobehavioral and cognitive abilities in Spirulina supplemented protein deprived rats, the present study incorporates neurochemical and morphometric analysis of glial cells and neurons and revealed that maternal Spirulina consumption partially prevented the PMN associated neuropathological alterations in terms of attenuated oxidative brain damage, reduced reactive gliosis and apoptotic cell population, improved dendritic branch complexity with few damaged neurons and enhanced mushroom shaped spine density. The results suggest that cellular changes in hippocampus after PMN are partially restored after maternal Spirulina supplementation and one could envision intervention approaches using Spirulina against malnutrition.

Amelioration of neurobehavioral and cognitive abilities of F1 progeny following dietary supplementation with Spirulina to protein malnourished mothers

Early life adversities (stress, infection and mal/undernutrition) can affect neurocognitive, hippocampal and immunological functioning of the brain throughout life. Substantial evidence suggests that maternal protein malnutrition contributes to the progression of neurocognitive abnormalities and psychopathologies in adolescence and adulthood in offspring. Maternal malnutrition is prevalent in low and middle resource populations. The present study was therefore undertaken to evaluate the effects of dietary Spirulina supplementation of protein malnourished mothers during pregnancy and lactation on their offspring's reflex, neurobehavioral and cognitive development. Spirulina is a Cyanobacterium and a major source of protein and is being used extensively as a dynamic nutraceutical against aging and neurodegeneration. Sprague Dawley rats were switched to low protein (8% protein) or normal protein (20% protein) diet for 15 days before conception. Spirulina was orally administered (400 mg/kg/b.wt.) to subgroups of pregnant females from the day of conception throughout the lactational period. We examined several parameters including reproductive performance of dams, physical development, postnatal reflex ontogeny, locomotor behavior, neuromuscular strength, anxiety, anhedonic behavior, cognitive abilities and microglia populations in the F1 progeny. The study showed improved reproductive performance of Spirulina supplemented protein malnourished dams, accelerated acquisition of neurological reflexes, better physical appearance, enhanced neuromuscular strength, improved spatial learning and memory and partly normalized PMN induced hyperactivity, anxiolytic and anhedonic behavior in offspring. These beneficial effects of Spirulina consumption were also accompanied by reduced microglial activation which might assist in restoring the behavioral and cognitive skills in protein malnourished F1 rats. Maternal Spirulina supplementation is therefore proposed as an economical nutraceutical/supplement to combat malnutrition associated behavioral and cognitive deficits.

Maternal Protein Malnutrition: Current and Future Perspectives of Spirulina Supplementation in Neuroprotection

Malnutrition has been widely recognized as a grave burden restricting the progress of underdeveloped and developing countries. Maternal, neonatal and postnatal nutritional immunity provides an effective approach to decrease the risk of malnutrition associated stress in adulthood. Particularly, maternal nutritional status is a critical contributor for determining the long-term health aspects of an offspring. Maternal malnutrition leads to increased risk of life, poor immune system, delayed motor development and cognitive dysfunction in the children. An effective immunomodulatory intervention using nutraceutical could be used to enhance immunity against infections. The immune system in early life possesses enormous dynamic capacity to manage both genetic and environment driven processes and can adapt to rapidly changing environmental exposures. These immunomodulatory stimuli or potent nutraceutical strategy can make use of early life plasticity to target pathways of immune ontogeny, which in turn could increase the immunity against infectious diseases arising from malnutrition. This review provides appreciable human and animal data showing enduring effects of protein deprivation on CNS development, oxidative stress and inflammation and associated behavioral and cognitive impairments. Relevant studies on nutritional supplementation and rehabilitation using Spirulina as a potent protein source and neuroprotectant against protein malnutrition (PMN) induced deleterious changes have also been discussed. However, there are many futuristic issues that need to be resolved for proper modulation of these therapeutic interventions to prevent malnutrition.

Intra-generational protein malnutrition impairs temporal astrogenesis in rat brain

The lack of information on astrogenesis following stressor effect, notwithstanding the imperative roles of astroglia in normal physiology and pathophysiology, incited us to assess temporal astrogenesis and astrocyte density in an intra-generational protein malnutrition (PMN) rat model. Standard immunohistochemical procedures for glial lineage markers and their intensity measurements, and qRT-PCR studies, were performed to reveal the spatio-temporal origin and density of astrocytes. Reduced A₂B₅+ glia restricted precursor population in ventricles and caused poor dissemination to cortex at embryonic days (E)11-14, and low BLBP+ secondary radial glia in the subventricular zone (SVZ) of E16 low protein (LP) brains reflect compromised progenitor pooling. Contrary to large-sized BLBP+ gliospheres in high protein (HP) brains at E16, small gliospheres and discrete BLBP+ cells in LP brains evidence loss of colonization and low proliferative potential. Delayed emergence of GFAP expression, precocious astrocyte maturation and significantly reduced astrocyte number suggest impaired temporal and compromised astrogenesis within LP-F1 brains. Our findings of protein deprivation induced impairments in temporal astrogenesis, compromised density and astrocytic dysfunction, strengthen the hypothesis of astrocytes as possible drivers of neurodevelopmental disorders. This study may increase our understanding of stressor-associated brain development, opening up windows for effective therapeutic interventions against debilitating neurodevelopmental disorders.

Summary: Maternal protein deprivation results in low progenitor pooling, and delayed and compromised astrogenesis, suggesting astrocyte impairment as a driver of neurological diseases owing to their imperative roles in normal and pathological situations.

Slow Physical Growth, Delayed Reflex Ontogeny, and Permanent Behavioral as Well as Cognitive Impairments in Rats Following Intra-generational Protein Malnutrition

Environmental stressors including protein malnutrition (PMN) during pre-, neo- and post-natal age have been documented to affect cognitive development and cause increased susceptibility to neuropsychiatric disorders. Most studies have addressed either of the three windows and that does not emulate the clinical conditions of intra-uterine growth restriction (IUGR). Such data fail to provide a complete picture of the behavioral alterations in the F1 generation. The present study thus addresses the larger window from gestation to F1 generation, a new model of intra-generational PMN. Naive Sprague Dawley (SD) dams pre-gestationally switched to LP (8% protein) or HP (20% protein) diets for 45 days were bred and maintained throughout gestation on same diets. Pups born (HP/LP dams) were maintained on the respective diets post-weaningly. The present study aimed to show the sex specific differences in the neurobehavioral evolution and behavioral phenotype of the HP/LP F1 generation pups. A battery of neurodevelopmental reflex tests, behavioral (Open field and forelimb gripstrength test), and cognitive [Elevated plus maze (EPM) and Morris water maze (MWM)] assays were performed. A decelerated growth curve with significantly restricted body and brain weight, delays in apparition of neuro-reflexes and poor performance in the LP group rats was recorded. Intra-generational PMN induced poor habituation-with-time in novel environment exploration, low anxiety and hyperactive like profile in open field test in young and adult rats. The study revealed poor forelimb neuromuscular strength in LP F1 pups till adulthood. Group occupancy plots in MWM test revealed hyperactivity with poor learning, impaired memory retention and integration, thus modeling the signs of early onset Alzehemier phenotype. In addition, a gender specific effect of LP diet with severity in males and favoring female sex was also noticed.

Differential temporal expression of S100β in developing rat brain

Radial glial cells (RGs) originally considered to provide scaffold to the radially migrating neurons constitute a heterogeneous population of the regionally variable precursor cells that generate both neurons as well as glia depending upon the location and the timing of development. Hence specific immunohistochemical markers are required to specify their spatiotemporal location and fate in the neurogenic and gliogenic zones. We hypothesize S100β as a potential and unified marker for both primary and secondary progenitors. To achieve this, cryocut sections from rat brains of varied embryonic and postnatal ages were immunolabeled with a combination of antibodies, i.e., S100β + Nestin, Nestin + GFAP and S100β + GFAP. A large population of the primary and secondary progenitors, lining the VZ and SVZ, simultaneously co-expressed S100β and nestin establishing their progenitor nature. A downregulation of both S100β and nestin noticed by the end of the 1st postnatal week marks their differentiation towards neuronal or glial lineage. In view of the absence of co-expression of GFAP (glial fibrillary acidic protein) either with S100β or nestin, the suitability of accepting GFAP as an early marker of RG's was eliminated. Thus the dynamic expression of S100β in both the neural stem cells (NSCs) and RGs during embryonic and early neonatal life is associated with its proliferative potential and migration of undifferentiated neuroblasts and astrocytes. Once they lose their potential for proliferation, the S100β expression is repressed with its reemergence in mature astrocytes. This study provides the first clear evidence of S100β expression throughout the period of neurogenesis and early gliogenesis, suggesting its suitability as a radial progenitor cell marker.

TLR3 mediated innate immune response in mice brain following infection with Chikungunya virus

Chikungunya virus (CHIKV) has received global attention due to the series of large-scale outbreaks in different parts of the world. Many unusual clinical severities including neurological complications and death were reported in recent outbreaks. The mechanism underlying the host immune response to CHIKV in the brain is poorly characterized. In this study, the neuropathogenesis of CHIKV with E1:A226V mutation was elucidated in 1 week old BALB/c mice. The virus was found to replicate in mice brain with peak titer of 10(4) on 6th day post infection. Immunohistochemical analysis revealed preferential virus localization in neuronal cells of cerebellum. The expression profiling of TLR, antiviral genes and cytokines in mice brain revealed significant up regulation of TLR3, TRAF-6, TICAM-1, MCP-1, CXCL-10, IL-6, IL-4, ISG-15, MX-2, IFN-β, OAS-3 genes that ultimately resulted in virus clearance from brain by day 9-10 suggesting activation of innate immune pathway. Further the effect of poly I: C (Polyinosinic: Polycytidylic acid), a TLR-3 agonist and potent IFN inducer on CHIKV neuropathogenesis was studied. Pretreatment of mice with Poly I: C caused reduction of CHIKV titer in brain and offered 100% protection of animals. The protection was mediated by an increased induction of TLR3, IFN-β and antiviral genes in mice brain. Our result demonstrates that pre immune stimulation of animals by Poly I: C is effective inhibitor of CHIKV replication and might be a promising prevention agent against this virus.

Differential regulation of TLR mediated innate immune response of mouse neuronal cells following infection with novel ECSA genotype of Chikungunya virus with and without E1:A226V mutation

Chikungunya virus (CHIKV) has received global attention due to the series of large-scale outbreaks in different parts of the world including Africa, Indian Ocean Islands, India and South-East Asia. The appearance of many unusual severe manifestations including neurological disorders was reported in post resurgence epidemics with implication of novel East Central South African (ECSA) genotype with E1:A226V mutation. The molecular mechanism of CHIKV neuropathogenesis is not yet understood and very little is known about the host-pathogen interactions. In the present study replication kinetics and innate immune response of ECSA genotype of CHIKV with and without A226V mutation were determined in mouse neuroblastoma cell line (N2a). The 226V mutant strain was more replication competent in N2a cells with a peak titer of 10(8)PFU/ml compared to 10(6)PFU/ml for A226 virus. Besides, the 226V mutant virus showed relatively less induction of antiviral genes i.e. IFN-β, OAS-3, MX-2, ISG-15 and Toll like receptors 3 and 7 as compared to non mutant strain (A226). Further pretreatment of N2a cells either with Poly I: C, IFN-β or TNF-α resulted in inhibition of CHIKV replication hence confirming the role of TLR mediated innate immune response in CHIKV pathogenesis. Differential regulation of TLRs and associated down stream antiviral genes might have attributed for increased pathogenesis of the 226V mutant novel ECSA genotype of CHIKV during the recent epidemics.

Molecular epidemiology and complete genome characterization of H1N1pdm virus from India

Background

Influenza A virus is one of world’s major uncontrolled pathogen, causing seasonal epidemic as well as global pandemic. This was evidenced by recent emergence and continued prevalent 2009 swine origin pandemic H1N1 Influenza A virus, provoking first true pandemic in the past 40 years. In the course of its evolution, the virus acquired many mutations and multiple unidentified molecular determinants are likely responsible for the ability of the 2009 H1N1 virus to cause increased disease severity in humans. Availability of limited data on complete genome hampers the continuous monitoring of this type of events. Outbreaks with considerable morbidity and mortality have been reported from all parts of the country.

Methods/Results

Considering a large number of clinical cases of infection complete genome based sequence characterization of Indian H1N1pdm virus and their phylogenetic analysis with respect to circulating global viruses was undertaken, to reveal the phylodynamic pattern of H1N1pdm virus in India from 2009–2011. The Clade VII was observed as a major circulating clade in phylogenetic analysis. Selection pressure analysis revealed 18 positively selected sites in major surface proteins of H1N1pdm virus.

Conclusions

This study clearly revealed that clade VII has been identified as recent circulating clade in India as well globally. Few clade VII specific well identified markers undergone positive selection during virus evolution. Continuous monitoring of the H1N1pdm virus is warranted to track of the virus evolution and further transmission. This study will serve as a baseline data for future surveillance and also for development of suitable therapeutics.

Rotenone-induced apoptosis and role of calcium: a study on Neuro-2a cells

Rotenone causes cytotoxicity in astrocytic cell culture by glial activation, which is linked to free radical generation. The present study is an investigation to explore whether rotenone could also cause cellular toxicity in mouse neuroblastoma cells (Neuro-2a) under treatment similar to astroglial cells. The effect of rotenone (0.1, 1, and 10 μM) on mitochondrial dehydrogenase enzyme activity by MTT reduction assay, PI uptake, total reactive oxygen species (ROS)/superoxide levels, nitrite levels, extent of DNA damage (by comet assay), and nuclear morphological alteration by Hoechst staining was studied. Caspase-3 and Ca⁺²/calmodulin-dependent protein kinase II (CaMKIIα) gene expression was determined to evaluate the apoptotic cell death and calcium kinase, respectively. Calcium level was estimated fluorometrically using fura-2A stain. Rotenone decreased mitochondrial dehydrogenase enzyme activity and generated ROS, superoxide, and nitrite. Rotenone treatment impaired cell intactness and nuclear morphology as depicted by PI uptake and chromosomal condensation of Neuro-2a cells, respectively. In addition, rotenone resulted in increased intracellular Ca⁺² level, caspase-3, and CaMKIIα expression. Furthermore, co-exposure of melatonin (300 μM), an antioxidant to cell culture, significantly suppressed the rotenone-induced decreased mitochondrial dehydrogenase enzyme activity, elevated ROS and RNS. However, melatonin was found ineffective to counteract rotenone-induced increased PI uptake, altered morphological changes, DNA damage, elevated Ca⁺², and increased expression of caspase-3 and CaMKIIα. The study indicates that intracellular calcium rather than oxidative stress is a major factor for rotenone-induced apoptosis in neuronal cells.

ICV STZ induced impairment in memory and neuronal mitochondrial function: A protective role of nicotinic receptor

The present study was planned to evaluate the cholinergic influence on mitochondrial activity and neurodegeneration associated with impaired memory in intracerebroventricular (ICV) streptozotocin (STZ) treated rats. STZ (3mg/kg), administered ICV twice with an interval of 48h between the two doses, showed significant impairment in spatial memory tested by water maze test 14 days after first dose without altering blood glucose level and locomotor activity. Animals were sacrificed on 21st day of ICV administration. STZ significantly increased malondialdehyde (MDA), reactive oxygen species (ROS), Ca(2+) ion influx, caspase-3 activity and decreased glutathione (GSH) level. Acetylcholinesterase inhibitors tacrine and donepezil (5mg/kg, PO) pretreatment significantly prevented STZ induced memory deficit, oxidative stress, Ca(2+) influx and caspase-3 activity. Carbachol, a muscarinic cholinergic agonist (0.01mg/kg, SC) did not show any significant effect on ROS generation, Ca(2+) ion influx and caspase-3 activity. While nicotinic cholinergic agonist, nicotine, significantly attenuated ICV STZ induced mitochondrial dysfunction and caspase-3 activity. The results indicate that instead of muscarinic receptors nicotinic receptors may be involved in neuroprotection by maintaining mitochondrial functions.

Iba1 expressing microglia in the dorsal root ganglia become activated following peripheral nerve injury in rats

The presence of microglia in dorsal root ganglia (DRG) has not been reported earlier. The dorsal root ganglia contain satellite glial cells (SGCs) and macrophages, which are considered to have infiltrated from the systemic blood. An attempt was made to investigate whether microglia as found in the central nervous system are also present in the dorsal root ganglia of untreated rats and following experimental peripheral nerve injury. Female adult Wistar rats were subjected to sciatic nerve transection injury on the right hand side. The DRGs of the right side were studied with the contralateral DRGs of the left side serving as controls. The tissues, harvested at different time points after injury, following intracardial perfusion fixation, and frozen sections were immunolabeled with anti-GFAP as a marker for SGCs and anti-Iba1 and OX-6 as markers for microglia and activated macrophagic microglia, respectively. These antibodies were also used in combination to ascertain if Iba1+ cells are the SGCs or otherwise and also if macrophagic OX-6+ cells are Iba1 positive microglia. The results indicate that Iba1 positive microglial cells are different from the SGCs in the DRGs. The Iba1 positive microglial cells respond to the sciatic nerve injury becoming activated and macrophagic and express MHCII molecules. Such activated microglia apparently may serve as neurosupportive cells, providing neuroprotection and scavenging cellular debris in response to the injury.

Poly I:C induced microglial activation impairs motor activity in adult rats

Polyinosinic:polycytidic acid (poly I:C) is a synthetic double stranded RNA, which mimics with viral genome and mediates immune activation response similar to double stranded RNA virus infection into the brain. Microglial cells are the immune competent cells of the central nervous system having Toll like receptors-3 on their surface. Upon establishing that poly I:C infusion into the brain causes microgliosis by creating a viral infection model, the present study was designed to evaluate the effects of microglial activation following poly I:C infusion on motor activity. We infused 100 microl of 1% solution of Poly I:C in TBE buffer directly into the lateral ventricle and TBE buffer as vehicle to controls. A significantly higher microglial cell count as compared to control on 2, 3 and 7 days post infusion was recorded. Motor activity and microglial cell count was assessed in both controls and poly I:C infused rats on 1, 2, 3, 7, 14, 21 and 28 days post infusion. A significant decrease in motor activity and motor coordination occurred with respect to control. The results clearly demonstrate that microglial activation has a direct relevance with decreased motor activity. Findings could also have their importance in understanding the role of microglial cells on behavioral aspects in viral diseases.

S100beta upregulation: a possible mechanism of deltamethrin toxicity and motor coordination deficits

Deltamethrin (DLT) is a type II synthetic pyrethroid with insecticidal properties. It has been considered safe to humans. Excessive exposure of DLT is being variously reported, recently, to cause potential neurotoxicity in adults, as characterized by ataxia, loss of coordination, hyperexcitability, convulsions and paralysis. However, limited information is available on its impact at lower/safe to human doses during development. The present study was designed to assess the postnatal (P) exposure of DLT (as low as 0.7 mg/kg, i.p.) on S-100beta expression in developing rat cerebellum and its impact on Purkinje cell morphogenesis and dendritogenesis, and subsequent spontaneous motor activity (SMA) deficits. Wistar rat pups born to healthy mothers were injected with DLT (Sigma) at a dosage of 0.7 mg/kg body wt., i.p. dissolved in DMSO (Sigma) during P0-7th (DLT-I) and P9-13th day (DLT-II). The control pups were injected with equivalent volumes of DMSO. The pups of both the groups were used to assess the spontaneous motor activity P21 onwards. The cryocut sections (30 microm) of the cerebella were used for anti-S-100beta antibody labeling using streptavidin biotin HRP method. An upregulation of S-100beta expression in Bergmann glial fibers was recorded at P12 and P15 day preparations in both DLT-I and DLT-II treated groups. However, such upregulation of S-100beta was more prominent in DLT-II treated group animals with a large number of strongly S-100beta immunopositive astrocytes flanking around the Purkinje neurons. In Golgi preparation the Purkinje neurons in DLT treated groups had reduced dendritic arbor with short primary dendrites and much reduced dendritic branches which appeared stumpy and hypertrophied. The granule cell proliferation and migration as well as Purkinje cell morphogenesis and dendritogenesis are affected following DLT exposure in the present investigation. This may also affect the mossy fiber-granule cell-parallel pathway formation which in turn may decrease the firing of Purkinje cells (GABAergic inhibitory projections) and thus an increase in the output of the neurons in the deep cerebellar nuclei neurons and disturbed motor coordination.

Effects of deltamethrin on granule cell migration during postnatal development of rat cerebellum

Deltamethrin (DLT; 0.7mg/kg/body wt/day, i.p., dissolved in propylene glycol) administration during postnatal days 913 in Albino rat pups, resulted in a delayed appearance of radial glial fibers, that guide the migration of granule cells. Moreover, the radial glial fibers in the DLT-treated pups were disorganized, hypertrophied and heavily stained. Thus, it is being proposed that although after exposure to DLT the neuronal proliferation occurs at normal rate, the neuronal migration along the stumpy and crumpled radial fibers hamper the journey of the healthy neurons to their proper destination.

Flunarizine enhances functional recovery following sciatic nerve crush lesion in rats

We have used the rat sciatic nerve crush (SNC) injury model to assess the neuroprotective effects of flunarizine (FNZ), a calcium channel antagonist and a vasodilator. The animals were treated with FNZ for various durations following SNC (0.33 mg/kg per day, i.p). Employing the physical disector method, we quantitated the rates of neuron loss in the dorsal root ganglion and spinal cord and protective effects of FNZ. FNZ treatment following SNC reduced neuron loss up to 86.6 and 82.5% in DRG sensory and spinal cord motor neurons, respectively. Functional recovery following SNC with or without FNZ treatment was assessed using the measurements of the total, 1-5 and 2-4-toe spread to quantitate percentage relative toe spread in relation to the respective controls. FNZ provided a superior return of function, i.e. near absolute recovery of both sensory and motor functions in 4 weeks, which is consistent with its neuroprotective effects.

Lipofuscin accumulation in ageing myocardium & its removal by meclophenoxate

A study was undertaken on the age-associated histochemical changes in the ventricular myocardium and the influence of meclophenoxate hydrochloride (MPH) on the age pigment lipofuscin. Sixty Wistar albino rats in three age-groups (3, 15 and 30 months old) were treated with meclophenoxate hydrochloride (100 mg/kg body wt/day, ip) for a period of 2-8 wk. Five animals each from the three age-groups served as controls. Various histochemical and micromorphometric studies were carried out on the myocardial tissue. A linear increase in the myocardial volume occupied by the pigment was observed with advancing age. As a result of meclophenoxate treatment, a gradual decrease in the myocardial volume occupied by the pigment was noted. After 4-6 wk treatment, the pigment bodies were found lodged into the capillary endothelium and the lumen, facilitating the removal of the pigment via blood stream. Histochemical and micromorphometric analyses of ventricular myocardium of albino rats have shown thus that deposition of the age-pigment, lipofuscin, can be accepted as an index of cellular ageing.

'Dark' cell formation under protein malnutrition: process of conversion and concept of 'semi-dark' type Purkinje cells

This paper deals with some deleterious effects of protein malnourishment in rat cerebellum. Severe protein deprivation enhanced the formation of 'dark' cells in white rats. It is postulated that abnormal changes in the neuronal contents induced by nutritional stress play a vital role in the formation of the 'dark' cells through an intermediary stage, 'semi-dark' cells. Centrophenoxine a lipofuscinolytic agent, however, seems to interfere with the process of formation of 'dark' cells and/or helps reconversion of the 'dark' cells into the normal or 'light' type Purkinje cells.

Cytochemical interaction of nucleolus and cytoplasm in the Purkinje cells of senile white rats under the influence of centrophenoxine

Senile white rats were treated with centrophenoxine at a dosage of 100 mg/Kg body weight/day for 60 days intraperitoneally. Sections of variously fixed and embedded cerebella were studied cytochemically to note the effect of the drug on the senile Purkinje neurons. The nucleolus was found to be hyper-active, as evidenced by the processes of budding and extrusion. A frank regeneration of the Nissl patches along with an increase in alpha-esterase and decrease in the activity of acid phosphatase and simple esterase was noted in the Purkinje cells after 60 days' treatment. It is suggested that the drug exerts its positive effects by regenerating the general cytoplasm and by revitalizing the nucleocytoplasmic interactions in the senile Purkinje cells.