Potential effect of Nigella sativa against Diethylnitrosamine-induced hepatocarcinogenesis in rats

Objective of the investigation was the study of potential protective effects of the watery extract of Nigella sativa against diethylnitrosamine induced hepatocarcinogenesis in rats. N. sativa was administered to rats for protection against diethylnitrosamine-induced hepatocarcinogenesis. It was administered prior to, simultaneously with or after injection of diethylnitrosamine. Five groups of Wister rats were used. Group A was administered diethylnitrosamine and N. sativa simultaneously, group B was administered only diethylnitrosamine and group C received only N. sativa. These three groups were maintained for up to eight weeks. Group D received N. sativa six weeks after administration ofdiethylnitrosamine,while group E (“protective group”) received N. sativa on day 1 and diethylnitrosamine six weeks later. These two groups were maintained for up to 12 weeks. All rats were subjected to partial hepatectomy to enhance carcinogenesis. P-isoform of glutathione s transferase (GST-P) was detected in the cytoplasm and nuclei of hepatocytes. The number of GST-P positive foci was significantly smaller in test groups (A, D, E), particularly in groups A and E, when compared with to those in group B, indicating that N. sativa has protective effects against diethylnitrosamine induced liver cancer in rats, even in the very early stages of hepatocarcinogenesis

Neuropathology of aging in cats and its similarities to human Alzheimer’s disease

Elderly cats develop age-related behavioral and neuropathological changes that ultimately lead to cognitive dysfunction syndrome (CDS). These neuropathologies share similarities to those seen in the brains of humans with Alzheimer’s disease (AD), including the extracellular accumulation of ß-amyloid (Aβ) and intraneuronal deposits of hyperphosphorylated tau, which are considered to be the two major hallmarks of AD. The present study assessed the presence and distribution of Aβ and tau hyperphosphorylation within the cat brain (n = 55 cats), and how the distribution of these proteins changes with age and the presence of CDS. For this, immunohistochemistry was performed on seven brain regions from cats of various ages, with and without CDS (n = 10 with CDS). Cats accumulate both intracytoplasmic and extracellular deposits of Aβ, as well as intranuclear and intracytoplasmic hyperphosphorylated tau deposits. Large extracellular aggregates of Aβ were found in elderly cats, mainly in the cortical brain areas, with occasional hippocampal aggregates. This may suggest that these aggregates start in cortical areas and later progress to the hippocampus. While Aβ senile plaques in people with AD have a dense core, extracellular Aβ deposits in cats exhibited a diffuse pattern, similar to the early stages of plaque pathogenesis. Intraneuronal Aβ deposits were also observed, occurring predominantly in cortical brain regions of younger cats, while older cats had few to no intraneuronal Aβ deposits, especially when extracellular aggregates were abundant. Intracytoplasmic hyperphosphorylated tau was found within neurons in the brains of elderly cats, particularly in those with CDS. Due to their ultrastructural features, these deposits are considered to be pre-tangles, which are an early stage of the neurofibrillary tangles seen in AD. The largest numbers of pre-tangles are found mainly in the cerebral cortex of elderly cats, whereas lower numbers were found in other regions (i.e., entorhinal cortex and hippocampus). For the first time, intranuclear tau was found in both phosphorylated and non-phosphorylated states within neurons in the cat brain. The highest numbers of intranuclear deposits were found in the cortex of younger cats, and this tended to decrease with age. In contrast, elderly cats with pre-tangles had only occasional or no nuclear labelling

Studies of the histopathological changes and presence of amyloid b protein (Ab) deposits in the aged feline brain

A wide variety of age-related changes has been described in the brain of many species. The aim of this study was to detect the histological lesions as well as the peptides of Αβ-forming amyloid deposits in the aged feline brain. Additionally, an effort was made to assess the usefulness of the cat as a natural animal model of normal aging and neurodegenerative diseases in humans. 20 aged cats (7,5-21 years old) and 3 control cats (0,6-3 years old) were used in this study. The cats were either admitted dead for necropsy or euthanised due to debilitating non-neurological disorders. The brains were routinely fixed and samples were collected from the frontal, parietal and temporal lobes, the hippocampus, the corpus striatum, the thalamus, and the cerebellum, for histological and immunohistochemical examination. Subsequently, serial paraffin sections from all samples were stained with hematoxylin and eosin (HE), periodic acid Schiff (PAS), Kluver-Barrera’s luxol fast blue, modified alkaline Congo red and modified Bielschowsky. Single-labelling immunostaining by avidin-biotin peroxidase complex (ABC) method was also performed on adjacent sections, to detect ΑβPP and other Αβ peptides as well as to examine the reaction of astrocytes. Histologically, diffuse fibrosis of the choroid plexus and the meninges was seen. Vascular fibrosis and/or hyalinosis were detected in the same tissues as well as in the brain parenchyma. Μeningeal and choroid plexus vessels were often calcified. The perivascular presence of PAS- positive foamy cells was an invariable feature. Satelitosis, neuronophagia and PAS positive granular lipofuskin deposits within the cytoplasm of neurons and microglial cells were also constant findings. Neuronal degeneration and necrosis were found in all samples examined. The intensity of degenerative and necrotic lesions correlated positively with the age of the cats. White and grey matter vacuolation, neuraxonal degeneration, reactive gliosis, and presence of lafora bodies and spheroids, were additional findings in all aged animals. In a few brains, spherical to ovoid structures stained exclusively with H-E were occasionally noticed. The immunohistochemical study revealed age-dependent isomorphic gliosis and accumulation of AβPP exclusively into the cytoplasm of both neuronal and choroid plexus epithelial cells. Moreover, Aβ42 and Aβ40 peptides and less commonly Aβ (8-17) and Panβ (15-30) were evident in the neuronal cytoplasm, the wall of meningeal and parenchymal vessels as well as in the neuropil and the extracellular space of the white matter. The SP consisted of non-fibrillar Aβ and were classified into two distinct types: diffuse and stellate. The diffuse SP were divided into two subtypes: condensed and cloud-like, both comprising mainly of Aβ42 and Αβ40 peptides. In contrast, the stellate SP were formed exclusively by Aβ42. Finally, it is noteworthy that the Aβ40 and Αβ42 peptides were also detected in the cytoplasm of choroid plexus epithelial cells. The histopathological findings and the depositions of Αβ were gradually increased with age. The spectrum of lesions characterizing the aged cats was not observed in the brains of the control animals. A comparative study of brain lesions among aged animals of different breeds concluded that Σιάμ cats appear to be more susceptible to age-related lesions than DSH and DLH. In conclusion, the histopathological findings, the localization and nature of total Aβ and of Aβ peptides and the reaction of astrocytes in the brain of aged cats is similar in many ways with those of humans with AD or non-demented aged humans. Thus, we suggest that the cat may be a suitable animal model of human neurodegenerative and age-related diseases.Αλλοιώσεις του εγκεφάλου που συνδέονται με την πάροδο της ηλικίας, έχουν αναφερθεί σε διάφορα είδη ζώων και τον άνθρωπο. Στην παρούσα έρευνα μελετήθηκαν οι ιστοπαθολογικές αλλοιώσεις, καθώς και η παρουσία των διάφορων πεπτιδίων της πρωτεΐνης Αβ, τα οποία συγκροτούν τις εναποθέσεις β αμυλοειδούς, στον εγκέφαλο των παρήλικων γατών. Επίσης, εκτιμήθηκε η δυνατότητα χρησιμοποίησης της γάτας ως ζώο-πρότυπο για τη μελέτη της γήρανσης και των διάφορων νευροεκφυλιστικών νοσημάτων του ανθρώπου. Για την έρευνα αυτή χρησιμοποιήθηκαν συνολικά 23 γάτες από τις οποίες οι 20 ήταν παρήλικες (7,5-21 ετών) και οι 3 νεαρής ηλικίας (0,6-3 ετών). Οι τελευταίες χρησιμοποιήθηκαν ως μάρτυρες. Τα ανωτέρω ζώα δεν εμφάνιζαν κλινικά συμπτώματα, που να προέρχονται από το ΚΝΣ και ιδιαίτερα από τον εγκέφαλο. Μετά το θάνατο ή την ευθανασία των ζώων λαμβάνονταν αμέσως ιστοτεμάχια από το μετωπιαίο, το βρεγματικό και τον κροταφικό λοβό, τον ιππόκαμπο, την παρεγκεφαλίδα, το θάλαμο και το ραβδωτό σώμα για ιστοπαθολογική και ανοσοϊστοχημική εξέταση. Ειδικότερα, για την ιστοπαθολογική εξέταση όλων των παραπάνω περιοχών χρησιμοποιήθηκαν διαδοχικές τομές παραφίνης και εφαρμόστηκαν συνολικά 5 ιστολογικές μέθοδοι (Η-Ε, PAS, Kluver-Barrera, τροποποιημένες χρώσεις του ερυθρού του Κογκό και Bielschowsky). Παράλληλα, για την ανοσοϊστοχημική εξέταση εφαρμόστηκε η μέθοδος ABC με στόχο την ανίχνευση, τόσο της ΑβPP και των διάφορων πεπτιδίων της Αβ, όσο και του βαθμού ενεργοποίησης των αστροκυττάρων. Οι ιστοπαθολογικές αλλοιώσεις χαρακτηρίζονταν από την παρουσία ίνωσης, που αφορούσε το χοριοειδές πλέγμα και τις μήνιγγες, καθώς και ίνωσης ή/και υαλίνωσης, που διαπιστώθηκαν στα αγγεία των ίδιων περιοχών και του εγκεφάλου. Επιπλέον, σχετικά συχνό εύρημα αποτελούσε η ασβεστοποίηση των αγγείων των μηνίγγων και του χοριοειδούς πλέγματος. Επιπρόσθετα, χαρακτηριστική ήταν η διαπίστωση στον εγκέφαλο αρκετών ζώων, της παρουσίας μικρονευρογλοιακών κυττάρων, που εντοπίζονταν συνήθως περιαγγειακά και έφεραν κενοτόπια στο κυτταρόπλασμά τους. Η δορυφόρωση, οι νευρωνοφαγίες και η συγκέντρωση κοκκίων λιποφουσκίνης στο κυτταρόπλασμα των νευρώνων και των μικρονευρογλοιακών κυττάρων αποτελούσαν σταθερά ευρήματα για όλα τα παρήλικα ζώα που εξετάστηκαν. Η εκφύλιση και η νέκρωση των νευρώνων διαπιστώθηκαν σε όλες τις περιοχές του εγκεφάλου των παρήλικων γατών, με την έντασή τους να αυξάνεται με την πάροδο της ηλικίας. Τέλος, σωμάτια Lafora, σφαιροειδή, κενοτόπια στη φαιά και τη λευκή ουσία του εγκεφάλου, εκφύλιση των νευρικών ινών και ενεργοποίηση των αστροκυττάρων διαπιστώθηκαν στην πλειονότητα των εγκεφάλων που εξετάστηκαν, ενώ λίγα ήταν τα περιστατικά στα οποία παρατηρήθηκαν σωμάτια που ανιχνεύονταν μόνο με τη χρώση Η-Ε

A novel deletion in the LTR region of a Greek small ruminant lentivirus may be associated with low pathogenicity

International audienceGreek small ruminant lentivirus (SRLV) strains remain relatively uncharacterized at the molecular level, despite the fact that lentiviral diseases of small ruminants are known to be widespread in the country. In the present study, we investigated the sequence diversity of the LTR region in Greek SRLV strains from sheep with and without disease symptoms, since sequence differences within this genomic area have been shown to lead to SRLV`s with distinct replication rates. The AP-4 and AML (vis) motifs and the TATA-box were highly conserved among Greek strains, whereas the two AP-1 sites exhibited some substitutions. Pairwise comparisons with reference strains revealed that Greek LTR sequences were closer to the ovine strains (25.7% average divergence) rather than the caprine strain CAEV (59.1 % average divergence). The most striking difference observed between the two groups of animals was a 13-14 nucleotide deletion in the strains obtained from the asymptomatic sheep. The deletion was located within the R region of LTR, which was also found to be much less homologous (39.6% average divergence) than the U3 and U5. Taken together, our data suggest that the R region of LTR may be involved in virus transcriptional activation. Furthermore, a specific deletion within this region may, at least in part, be associated with low pathogenicity of some SRLV strains