Maria Paola Ricciardi

Stress-induced morphohistochemical and functional changes in rat adrenal cortex, testis and major salivary glands.

The effect of repeated stress (1 h of daily immobilization for seven consecutive days) on the adrenal cortex of young adult male albino rats was evaluated by morphohistochemical methods and plasma assays; at the same time, testes and major salivary glands, as steroid-producing and -depending organs, respectively, were examined. Morphological and histochemical changes were found in the adrenal cortex, testis and submaxillary gland, though varying in degree and extent depending on the gland examined. Corticosterone and progesterone plasma levels increased, in agreement with the lipid depletion observed in the zona fasciculata, while testosterone and androstenedione decreased, as confirmed by the less marked enzymatic activity in the Leydig cells. The study thus proves that repeated stress, even of temporary duration, is able to influence directly or indirectly the morphofunctional state of the three examined glands, suggesting a functional linkage.

Expanded polytetrafluoroethylene as tendon replacement: an experimental study in chickens.

We designed an experimental animal model (in chickens) to assess the potential applications, above all in hand surgery, of an expanded polytetrafluoroethylene (e-PTFE) graft as a replacement for a natural tendon. The results of macroscopic, histological, and functional observations made five weeks, and three, four, five, and six months after implantation showed that the e-PTFE seemed to be a good replacement for tendons, because it integrated well with surrounding tissue and permitted good functional recovery within a reasonable time period.We designed an experimental animal model (in chickens) to assess the potential applications, above all in hand surgery, of an expanded polytetrafluoroethylene (e-PTFE) graft as a replacement for a natural tendon. The results of macroscopic, histological, and functional observations made five weeks, and three, four, five, and six months after implantation showed that the e-PTFE seemed to be a good replacement for tendons, because it integrated well with surrounding tissue and permitted good functional recovery within a reasonable time period.

Morphohistochemical relationships between adrenal cortex and major salivary glands in response to chronic suramin treatment.

Adult male albino rats received 18 mg/kg i.p. of suramin twice a week, comparable to the human therapeutic situation. Sacrifices took place after 30 and 60 days of treatment. Adrenal cortex and major salivary glands were examined, using morphological and histochemical methods, in order to obtain a) confirmation of adrenocortical damage reported previously and b) original data for the major salivary glands. In rats the submaxillary gland in particular has already been found to be closely related to the functional conditions of the adrenal cortex. In all organs examined, alterations already evident in 30 day-treated rats, were constantly more marked and widespread in 60 day-treated animals. At the end of the treatment the adrenal cortex showed morphological (poor differentiation of the zona glomerulosa, hypertrophic cell clusters in the zona fasciculata) and histochemical (different distribution of neutral lipids, cholesterol and delta 5-3 beta-hydroxysteroid dehydrogenase) changes. Damage (vacuolizations, lymphocytic infiltrates) observed in major salivary glands was shown to be more marked and widespread in the submaxillary gland, confirming its functional dependence on adrenocortical activity.

Age-related changes in the recovery of noradrenaline content in sympathetic fibres after reserpine treatment.

The aim of the present study was to evaluate noradrenaline recovery times in sympathetic fibres after reserpine administration by using fluorescence histochemical techniques. The spleen, the kidney, and the large intestine were examined 24 h to 15 d after reserpine treatment, in both young and aged male Sprague-Dawley rats, in order to establish not only the possible differences in recovery times of the various organs, but also if senescence can influence these times. The complete restoration of the noradrenaline content took place sooner in younger rats than in aged ones, and, within the same age-group, the recovery was quicker in the spleen and needed longer times in the large intestine, particularly in aged rats.

Bilateral dimorphism of Loewenthal's gland in young male albino rats: an ultrastructural investigation

This study represents a further contribution to our knowledge about the structure of Loewenthals gland. There are several divergences in the available literature on the topic, concerning both the histological and ultrastructural findings. However, in these studies, the authors did not take into account the potential influence of a putative side-dependent dimorphism previously reported by us. We therefore carried out histological and electronmicroscopic observations specifically aimed at evaluating the importance of the gland shape for its structure. In particular, in male albino rats aged 70-120 days, we compared the structure of the left and right glands. Depending on the side undergoing morphological investigation, we observed differences in the acini, cells, nuclei, endoplasmic reticulum, Golgi apparatus and granular content. Apart from slight individual differences, we found that structural variations were most frequently observed in glands displaying a more evident macroscopic side-specific dimorphism. Our findings demonstrate that several conflicting data in the literature dealing with the structure of Loewenthals glands might be explained by the morphofunctional side-dependent dimorphism of the organ.

Genetic modulation of PINK1 differentially affects mitophagy compared with autophagy disclosing common mechanisms of genetic and environmental parkinsonism

The second most frequent cause of autosomal recessive Parkinson’s disease is represented by mutations in the PTEN-induced putative kinase1 (PINK1). The PINK1 protein mainly localizes to mitochondria which are considered the target organelles mainly affected in Parkinson’s disease. In fact, parkinsonism-inducing neurotoxins such as rotenone, MPTP and methamphetamine all damage mitochondria. Therefore, the ability to counteract mitochondrial toxicity and promoting mitochondrial renewal by mithophagy and mitochondrial biogenesis is critical to cure Parkinsonism. For instance the autophagy-dependent removal of altered mitochondria known as mitophagy is supposed to be key in conteracting mitochondrial toxicity. Interestingly mitochondrial PINK1 is known to interact with autophagy proteins such as beclin1 and the ubiquitin-ligase parkin. Therefore, in the present study we evaluated whether such an interaction produced downstream effects leading to autophagy activation. This was evaluated through the simultaneous analysis of co-localization of parkin and beclin1 with the autophagy initiator ubiquitin. These phenomena were analyzed both at mitochondrial level and throughout the cytosol by analyzing autophagy-like vacuoles and LC3-II positive structures. Interestingly, despite increased mitophagy PINK1 overexpression did not produce a general activation of the autophagy pathway. It is likely that such a selective fashion of autophagy activation only limited to mitochondrial removal could explain the relevance of PINK1 for Parkinson’s disease but not for other neurodegenerative, autophagy-related disorders. The present data were obtained through several experimental settings featuring PINK1 overexpression, mutation, deletion and silencing of the gene. The effects were analyzed in baseline conditions but were supplemented by experiments in the presence of methamphetamine used here both as a mitochondrial neurotoxin and an autophagy-dependent Parkinsonism inducing compound. Data revealed that PINK1 was critical for mitochondria and cell viability already in baseline conditions though such an effect was magnified upon methamphetamine exposure. The present findings while explaining the molecular interactions which are likely to induce PINK1-dependent genetic Parkinsonism, provide a further evidence on the critical role of genetic and environmental alterations in the genesis of Parkinson’s disease.

Morphometrical evaluation of neurodegeneration: an integrated multiparametric approach using whole slide imaging

Assessing degree of neurodegeneration and eventually identifying a compound related neuroprotection can be much more arduous than one might imagine: number of animals, number of samples/animal, experimental design and statistics, together with the choice of proper IHC markers and the technology whereby they are evaluated are prominent factors in order to obtain reliable results. In acute models, histopathological measurements are an essential part of the experimental procedure; here we describe an integrated (qualitative/quantitative) histological assessment to be applied for the evaluation of neuroprotection in acute models of Huntington’s disease. We used whole slide imaging to validate a rat model of Huntington disease obtained by intrastriatal viral vector delivery of mutant huntingtin (Htt). Recombinant Adeno Associated Viral (AAV) vectors have been used successfully to transfer genes in a variety of tissues, including the brain, in adult animals [1]. Here we used rAAV9, charged with Exon 1 Htt carrying 17 and 138 CAG repeats. AAV9-Ex1- GFP-Q138 injection induced the formation of GFP positive Htt aggregates in the entire striatal area, increased GFAP and microglial activation with respect to Q17 injected striatum. NeuN, ChAT, GFAP, OX42 immunohistochemistry and GFP epifluorescence were evaluated contemporaneously to qualitatively evaluate the degree of induced lesions; qualitative evaluation allowed to exclude animals that have not responded to rAAV9 infection. The remaining selected animals were used for a multivariate statistical analysis based on whole slide imaging of immunohistochemically stained sections. We believe this approach increases results reliability when evaluating animal models of neurodegeneration.