Pastor García, Luis Miguel

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Pastor García, Luis Miguel

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Pastor García, Luis Miguel

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Universidad de Murcia. Departamento de Biología Celular e Histología

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Open Access
Ultrastructure of the tubular nephron of Testudo graeca (Chelonia). A comparison between hibernating and non-hibernating animals
(Murcia : F. Hernández, 1987) Zuasti, A.; Ferrer, C.; Ballesta Germán, José; Pastor García, Luis Miguel
The tubular nephron of hibernating and nonhibernating specimens of Testudo graeca (Chelonia) was studied by means of conventional light and electron microscopy and histochemistry. The tubular nephron was composed of proximal, intermediate, distal and collecting tubules in both hibernating and nonhibernating animals. The cells of the proximal tubule showed long microvilli, cytoplasmic vacuoles, a developed endoplasmic reticulum and abundant mitochondria. Fat droplets were also observed. The intermediate segment was lined by ciliated and nonciliated cells. The lining cells of the distal tubule presented few microvilli, abundant dense mitochondria and clear vesicles of mucous appearance in the terminal portion. Collecting ducts are composed of mucous and non-mucous cells. Mucous cells presented strong reaction to the histochemical techniques detecting sialoand sulpho-mucins. During hibernation, a progressive vacuolar degeneration of the endoplasmic reticulum was observed in al1 the segments of tubular nephron, which may be caused by a massive intake of extracellular water into the cell.
Open Access
Morphogenesis of rat experimental pulmonary emphysema induced by intratracheally administered papain: changes in elastic fibres
(Murcia : F. Hernández, 2006) Sánchez-Gascón, F.; Girona, J.C.; Bernal-Mañas, C.M.; Morales, E.; Canteras, M.; Beltrán Frutos, Ester; Pastor García, Luis Miguel
The ultrastructural changes of elastic fibres in emphysematous lungs have been studied in men, but few works exist on this topic in experimental emphysematous animals. In this paper, the morphogenesis of emphysema and alterations of the elastic fibres produced by the instillation of papain are described by light and electron microscopy. Wistar rats were instilled through the trachea with papain at a rate of 3 mg/100 g animal weight. The animals were sacrificed 12 h, 3 days, 10 days and 60 days after enzyme instillation. The "Mean Linear Intercept" (MLI), the "Number of fenestrations/respiratory units" (NF) the “Number of macrophages per mm of alveolar wall” (NM) and the "Number of respiratory unit/mm2” (RU), both in the control and experimental groups were studied. Two months after treatment, the experimental group showed a strong increase in the MLI (p<0.001) and NF (p<0.001), and a diminished number of RU (p<0.05) compared with the control group. Partial correlation analysis showed a positive correlation only between MLI and NF. Twelve hours after papain instillation an inflammatory response was observed, the elastic fibres were ruptured, while the microfibrilar component remained. New formations of eulanin elastic fibres were observed three days post papain instillation. After ten days the interalveolar oedema had disappeared and the elastic fibres were of normal morphology although irregular groups of strips of elastic fibres were evident. A mixed pattern of panlobular, centrilobular and normal lung zones were observed. Two months after papain instillation abundant accumulations of elastic fibres of irregular outline were observed associated to collagen fibres. In conclusion, the morphometric parameters studied showed a significant progression of the emphysema. The strong correlation between NF and MLI suggested that papain-induced emphysema is principally caused by breaches of the alveolar walls. The results seem to point to a very abnormal remodelling process associated with elastic fibre regeneration, although there were no signs of destruction of these new fibres formed in emphysematous rat lung induced by papain.
Open Access
Involution of seminiferous tubules in aged hamsters: an ultrastructural, immunohistochemical and quantitative morphological study
(Murcia : F. Hernández, 2004) Morales, E.; Horn, R.; Santamaria, L.; Pallarés, J.; Zuasti, A.; Ferrer, C.; Canteras, M.; Pastor García, Luis Miguel
In this study, we examined the age-related changes on morphometric parameters and ultrastructure of seminiferous tubules, and on the expression of extracellular matrix proteins in lamina propria of Syrian hamsters. A significant decrease in the percentage of normal tubules and an increase in the percentage of hypospermatogenic and arrested maturation tubules was observed with aging. Aged animals showed a decrease in tubular diameter, tubular lumen, seminiferous epithelium volume and total tubular volume. However, the total length of seminiferous tubules was significantly increased with aging. The most important ultrastructural changes with aging were the thickening of the lamina propria, the presence of diverse abnormalities in the spermiogenesis process, degeneration of germ cells, and vacuolization and flattening of Sertoli cells showing abundant lipofucsin droplets and residual bodies. Laminin immunoreactivity was found along the lamina propria of seminiferous tubules both in young and aged animals. Fibronectin immunoreactivity was found along the lamina propria and blood vessels. Both laminin and fibronectin total volume of immunostaining per testis was increased in aged hamsters. In conclusion, the agerelated changes in seminiferous tubules of hamster include: a decrease in tubular width and an increase in tubular length; widening of the lamina propria caused by a more extensive connective matrix between the peritubular cells and the basal membrane; and a strong disarrangement of the seminiferous epithelium, including germ cell degeneration and important alterations in both spermiogenesis and Sertoli cell structure.
Open Access
Heterogeneity of mesenchymal cells in human amniotic membrane at term
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2024) Cortés Sandoval, Salvador; Serrano Sánchez, Mª Isabel; Ferrer, Concepción; Delgado, Juan L.; Insausti, Carmen L.; Blanquer, Miguel; Beltrán Frutos, Ester; Martínez Hernández, Jesús; Pastor García, Luis Miguel; Seco Rovira, Vicente
There is increasing interest in understanding the tissue biology of human amniotic membrane (hAM) given its applications in medicine. One cellular component is mesenchymal cells, which can be extracted, cultured and differentiated "in vitro" into various cell types. These studies show that there is heterogeneity among mesenchymal cells. The aim of this work is to study the membrane "in situ" to determine whether this cellular heterogeneity exists. The hAMs were obtained from caesarean deliveries at term and analyzed by histological techniques. Types I-III mesenchymal cells and Hofbauer were distinguished by light microscopy. Histochemically, mesenchymal cell types showed successively increasing positivity to: PAS, vimentin, fibronectin, and Concanavalin-A; VGEF, TGF-β2, PDGF-C, FGF-2. By the semiquantitative point of view, the percentage of Type II cells was 60%, significantly higher than the other types. With transmission electron microscopy, an intermediate cell type between II-III was observed. Strong vesiculation of the rough endoplasmic reticulum (RER) with exocytosis was observed. In addition, an accumulation of a similar material to the extracellular matrix in the RER caused its dilation especially in type IIITEM cells. Some of this material acquired a globular structure. These structures were also found free in the extracellular matrix. In conclusion, the mesenchymal cells of the fibroblastic layer of the hAMs studied are heterogeneous, with some undifferentiated and others with a probably senescent fibroblastic phenotype with accumulation in their RER of fibronectin. These results may be of interest to extract mesenchymal cells from hAMs for use in regenerative medicine and to better understand the mechanisms of fetal membrane rupture
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Estudio microscopico del epitelio traqueal de Testudo graeca y pseudemys scripta elegans / Luis Miguel Pastor García.
(Murcia : Universidad,, 1985) Pastor García, Luis Miguel
Open Access
Extracellular vesicles would be involved in the release and delivery of seminal TGF-β isoforms in pigs
(Frontiers Media, 2023-02-10) Padilla, Lorena; Barranco, Isabel; Parra, Ana; Parrilla, Inmaculada; Rodríguez Martínez, Heriberto; Lucas, Xiomara; Roca, Jordi; Martínez Hernández, Jesús; Pastor García, Luis Miguel; Medicina y Cirugía Animal
Introduction: pig seminal plasma (SP) is rich in active forms of all three isoforms (1-3) of transforming growth factor β (TGF-β), a chemokine modulatory of the immune environment in the female genital tract once semen is delivered during mating or artificial insemination (AI). The present study aimed to examine how TGF-βs are secreted by the epithelium of the male reproductive tract and how they are transported in semen, emphasizing the interplay with seminal extracellular vesicles (sEVs). Methods: Source of TGF-βs was examined by immunohistochemistry in testis, epididymis, and accessory sex glands, by immunocytochemistry in ejaculated spermatozoa, and by Luminex xMAP® technology in SP and sEVs retrieved from healthy, fertile male pigs used as breeders in AI programs. Results: All three TGF-β isoforms were expressed in all reproductive tissues explored and would be released into ductal lumen either in soluble form or associated with sEVs. Ejaculated spermatozoa expressed all three TGF-β isoforms, both inside and outside, probably the outer one associated with membrane-bound sEVs. The results confirmed that pig SP contains all three TGF-β isoforms and demonstrated that a substantial portion of them is associated with sEVs. Discussion: Seminal EVs would be involved in the cellular secretion of the active forms of seminal TGF-β isoforms and in their safe transport from the male to the female reproductive tract.
Open Access
The oxytocin receptor in spermatozoa may originate from both spermatogenesis and epididymal maturation, and regulates capacitation
(Wiley, 2025-09-27) Garriga, Ferran; Ahmad, Adeel; Padilla, Lorena; Maside, Carolina; Bonet, Sergi; Barranco Cascales, Isabel; Roca, Jordi; Pastor García, Luis Miguel; Yeste, Marc; Martínez Hernández, Jesús; Medicina y Cirugía Animal; Facultad de Veterinaria
Background: The oxytocin receptor (OR) is a G-protein-coupled receptor recently identified in human spermatozoa, whose origin and role in sperm physiology remain unknown. Objectives: In this study, using the pig as a model, we examine the presence of the OR in ejaculated spermatozoa through immunofluorescence and immunoblotting, and investigate the receptor's origin in the male gamete via immunohistochemistry in testicular and epididymal tissues. Additionally, we assess the involvement of the OR in in vitro capacitation and the acrosome reaction by utilizing physiological concentrations of agonists (oxytocin and carbetocin) and an antagonist (L-371,257). Results: The results indicate that, in addition to the expected presence in ejaculated spermatozoa, the OR is expressed during spermatogenesis. Besides, this receptor is found in Leydig and Sertoli cells, as well as in the principal, basal, and apical cells of the epididymis. Furthermore, our data suggest that, during epididymal maturation, the OR could be incorporated in spermatozoa via extracellular vesicles within the apical blebs. The OR is involved in sperm capacitation, as the combination of the antagonist (L-371,257) and the agonist (carbetocin) increases intracellular calcium levels and membrane lipid disorders, which are known as capacitation markers. Conclusions: The presence of the OR in mammalian spermatozoa could originate from both spermatogenesis and epididymal maturation. Moreover, in the male gamete, this receptor regulates sperm capacitation by interacting with its ligand in the female reproductive tract.
Open Access
Histological changes in connective tissue of rat tails after bipolar radiofrequency treatment
(F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 2012) Bernal-Mañas, C.M.; Navarro, S.; Zuasti Elizondo, Adelina; Ferrer Cazorla, Concepción; Canteras Jordana, Manuel; García Collado, Angel Joaquín; Beltrán Frutos, Ester; Pastor García, Luis Miguel; Seco Rovira, Vicente; Facultades, Departamentos, Servicios y Escuelas::Departamentos de la UMU::Biología Celular e Histología
Radiofrequency (RF) has been included in the techniques used in aesthetic surgery/medicine. To date, no studies have performed a histological assessment of changes in the tissue after application of bipolar radiofrequency (BRF) with low energy and frequency. The aim of this study was to examine changes that are produced in connective tissue, principally in the fibroblasts, following BRF treatment. Four groups of rats received a different number of RF sessions (1, 2, 3 and 5). The following parameters were determined: the number of fibroblasts/unit area (FA), the proliferation index (PI), the Heat shock Protein 47 index (HSPI) and the percentage of connective tissue (PC). For statistical analysis, two subgroups (A and B) were made for the variables FA, PI and PC, and another two subgroups (C and D) for the variable HSPI. Significant differences for FA, PI and PC were observed between subgroups A and B, FA and PI having higher values in A, while PC had higher values in B. The HSPI in subgroup C showed significantly higher values than in D. Low energy and frequency BRF led to an increase in the number, proliferation and biosynthetic activity of fibroblasts. The resulting stress suffered by fibroblasts as a result of heat may be associated with the phenomenon of hormesis
Open Access
Testicular histomorphometry and the proliferative and apoptotic activities of the seminiferous epithelium in Syrian hamster during spontaneous recrudescence after exposure to short photoperiod
(© 2018 Blackwell Verlag GmbH., 2018-10-01) Ferrer Cazorla, Concepción; Canteras, Manuel; Sánchez-Huertas, María del Mar; Beltrán Frutos, Ester; Martínez Hernández, Jesús; Pastor García, Luis Miguel; Seco Rovira, Vicente; Biología Celular e Histología
Syrian hamsters are photoperiodic rodents in which reproduction, including testicular function, is stimulated by long photoperiod exposure and curtailed by exposure to a short photoperiod. The objectives of this study were to characterize the testis histomorphometrically and to determine the role of the proliferation and apoptosis phenomena in the recovery of the seminiferous epithelium during spontaneous recrudescence after exposure to short photoperiod. The study was performed using conventional light microscopy, proliferating cell nuclear antigen and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP in situ nick end labelling staining, image analysis software, and transmission electron microscopy in three recrudescence groups: initial recrudescence (IR), advanced recrudescence (AR), and total recrudescence (TR). Morphometrically, the results pointed to the gradual recovery of the testicular and tubular volumes, as well as of the seminiferous epithelium. Among the IR and AR groups, the increase in testicular and tubular volumes was accompanied by an increase in tubular diameter and length, with an increase in interstitial volume. From AR to TR, there was an increase in the tubular and total volumes, but, in this case, with a gradual increase in tubular diameter. Recovery of the seminiferous epithelium was accompanied by changes in apoptosis and proliferation activities. The first decreased half way through the process and the second remained higher than the control levels throughout the recrudescence stage. Ultrastructurally, alterations in the spermatozoa were observed, which indicated that spermiogenesis was not yet completely normal. In conclusion, spontaneous testicular recrudescence in Syrian hamster comprises two histomorphometrical phases, the first related to an increase in tubular length and diameter and interstitial volume, and the second depending principally on the gradual increase in tubular diameter. The restoration of the seminiferous epithelium is due to apoptosis reaching normal values in the AR group accompanied by higher proliferative activity than that observed in the Control group.
Open Access
Granulocyte-macrophage colony stimulating factor (GM-CSF) is fully expressed in the genital tract, seminal plasma and spermatozoa of male pigs
(Nature Research, 2020-08-07) Padilla, Lorena; Barranco, Isabel; Lucas, Xiomara; Rodríguez-Martínez, Heriberto; Roca, Jordi; Parrilla, Inmaculada; Martínez Hernández, Jesús; Pastor García, Luis Miguel; Medicina y Cirugía Animal
Granulocyte-macrophage colony stimulating factor (GM-CSF) is a pro-inflammatory cytokine identified in boar seminal plasma (SP) but until now unexplored in terms of place of production and its association to spermatozoa. This study aimed to explore these aspects by evaluating the presence of GM-CSF in porcine reproductive organs (testes, epididymis and accessory sex glands), SP and mature spermatozoa (from cauda epididymis and ejaculated) using Western blot (WB), immunohistochemistry and immunocytochemistry. Positive labelling was obtained in tissues, SP and spermatozoa. In reproductive organs, WB revealed three forms of GM-CSF with different glycosylation degrees (15, 31 and 40 kDa). In SP and epididymal fluid, the GM-CSF appeared only in its active form while in spermatozoa the GM-CSF form present varied among sperm sources. Non-viable spermatozoa showed more GM-CSF than viable spermatozoa (14.87 ± 1.98 RU vs. 7.25 ± 0.52 RU) of fluorescence intensity. In conclusion, GM-CSF is widely present in the reproductive tract of male pigs, attached to the spermatozoa already in the epididymis as well as verted to SP. Consequently, the GM-CSF ought to regulate male genital tract and sperm function as well as mediating initial inflammatory responses and further mediating later immune actions by the female to semen deposition.