Cat Tissues Research Articles

The comparison of pathogenicity among SARS-CoV-2 variants in domestic cats

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been detected or isolated from domestic cats. It is unclear whether cats play an important role in the SARS-CoV-2 transmission cycle. In this study, we examined the susceptibility of cats to SARS-CoV-2, including wild type and variants, by animal experiments. Cats inoculated with wild type, gamma, and delta variants secreted a large amount of SARS-CoV-2 for 1 week after the inoculation from nasal, oropharyngeal, and rectal routes. Only 100 TCID50 of virus could infect cats and replicate well without severe clinical symptoms. In addition, one cat inoculated with wild type showed persistent virus secretion in feces for over 28 days post-inoculation (dpi). The titer of virus-neutralizing (VN) antibodies against SARS-CoV-2 increased from 11 dpi, reaching a peak at 14 dpi. However, the omicron variant could not replicate well in cat tissues and induced a lower titer of VN antibodies. It is concluded that cats were highly susceptible to SARS-CoV-2 infection, but not to the Omicron Variant, which caused the attenuated pathogenicity.

Extracellular vesicles are involved in the paracrine communication between epithelial cells in different regions of the domestic cat epididymis†.

Sperm maturation depends on exposure to microenvironments within the different segments of the epididymis, but mechanisms underlying how these microenvironments are produced or maintained are not well understood. We hypothesized that epididymal extracellular vesicles could play a role in the process of maintaining microenvironments in different regions of the epididymis. Specifically, we tested whether the extracellular vesicles from different regions of the epididymis can ensure paracrine communication between cells in different segments. Domestic cat tissues were used to develop a reproducible in vitro culture system for corpus epididymis explants that were then exposed to extracellular vesicles collected from upstream (i.e., caput) segments. Impacts of different culture or exposure conditions were compared by analyzing the morphology, apoptosis, transcriptional activity, and gene expression in the explants. Here, we report the development of the first in vitro culture system for epididymal tissue explants in the domestic cat model. Using this system, we found that extracellular vesicles from the caput segment have a significant effect on the transcriptional profile of tissue from the corpus segment (1233 differentially expressed genes due to extracellular vesicle supplementation). Of note, expressions of genes associated with regulation of epithelial cell differentiation and cytokine signaling in the epididymis were influenced by the presence of extracellular vesicles. Together, our findings comprise the first report in any species of paracrine control of segmental gene regulation by epididymal extracellular vesicles. These results contribute to a better understanding of epididymis biology and could lead to strategies to enhance or suppress male fertility.

Selective extraction of genomic DNA from leopard cat (Prionailurus bengalensis), hairy-crowned deer (Elaphodus cephalophus) and muntjac (Muntiacus reevesi) using hydrophobic magnetic deep eutectic solvents

Wild animals, as a vital component of our natural world, serve a crucial role in preserving ecological equilibrium and biodiversity. By delving into the genetic constitution of wild animal populations, the evolutionary history, genetic diversity, and adaptation mechanisms could be explored, thereby informing conservation strategies and safeguarding the future of these species. In order to study the genetic information of wild animals, it is necessary to extract high purity and high concentration of wild animal genomic DNA. In this work, a hydrophobic magnetic deep eutectic solvent (HMDES) based vortexed extraction was developed for the extraction of genomic DNA from leopard cat (Prionailurus bengalensis), hairy-crowned deer (Elaphodus cephalophus) and muntjac (Muntiacus reevesi) muscle tissue, respectively. Extraction conditions like the pH value, extraction time, temperature and the amount of HMDES used were optimized by single-factor experiments. Under the optimized condition, genomic DNA could be selectively extracted from the three animal tissues. The limits of detection (LOD) and limits of quantification (LOQ) of the proposed method were 2.86 ng/μL and 8.66 ng/μL, respectively. Meanwhile, the relative standard deviation (RSD) of the method precision and repeatability were 1.64 % and 5.57 % at 20 ng/μL, showing the method has good precision and repeatability. After extraction, the DNA extracted into the HMDES droplets can be quickly recovered and the HMDES can be recycled and reused. The method proposed is a fast, environmental-friendly and high efficient extraction strategy for purification and enrichment of genomic DNA from leopard cat, hairy-crowned deer and muntjac tissues.

Molecular characterization of GPR84 in domestic cats

G protein-coupled receptor 84 (GPR84) was cloned as an orphan receptor, and medium-chain fatty acids were then revealed as endogenous ligands. GPR84 is expressed in immune cells and is believed to protect liver function from lipotoxicity caused by overeating and high-fat diet intake. This study aimed to present the molecular characterization of GPR84 in domestic cats. The deduced amino acid sequence of the feline GPR84 shows high sequence homology (83–89 %) with the orthologues from other mammalians by cDNA cloning of feline GPR84. Remarkably high mRNA expression was observed in the bone marrow by Q-PCR analysis. The inhibition of intracellular cAMP concentration was observed in cells transfected with feline GPR84 and treated with medium-chain fatty acids. Immunostaining of GPR84 and free fatty acid receptor 2 (FFAR2)/GPR43 in the bone marrow, where high mRNA expression was observed, showed reactions in macrophages and myeloid cells. To clarify whether the receptor formed homo/hetero-merization, GPR84 and FFARs were analyzed using Nano-Luc binary technology and NanoLuc bioluminescence resonance energy transfer technologies, which revealed that GPR84 formed more heteromers with FFAR2 than homomers with each other. In addition, when GPR84 and FFAR2/GPR43 were cotransfected in the cell, their localization on the cell membrane was reduced compared with that when single receptors were transfected. These results indicated that GPR84 is a functional receptor protein that is expressed in cat tissues and may have a protein–protein interaction with FFAR2/GPR43 on the cell membrane.

Evaluation of cat tumors in Samsun between 2004-2022

This study investigated the incidence of various tumors detected in 169 cat tissue and organ samples brought to the Samsun Ondokuz Mayis University, Veterinary Faculty, Department of Pathology between 2004–2022. Of the 169 specimens, five were acquired from necropsy and 164 were biopsy samples. Various tumors were evaluated retrospectively according to localization, sex, breed, and tumor origin. Tumors were common in mixed breeds (n = 96, 56.8%). Age of tumor incidence was examined; cats between 6 and 9 years of age most frequently had tumors (n = 45, 26.6%) in both sexes. In terms of tumor origin, 79 (47.0%) were mesenchymal, 83 (49.4%) were epithelial, and seven (4.2%) were of mixed components, i.e., mesenchymal and epithelial. In total, 147 (87%) tumors were classified as malignant and 22 (13%) tumors were classified as benign. Regardless of sex, the most commonly observed tumors were skin and subcutis tumors (n = 56, 32.1%). In conclusion, tumor incidence in Samsun was determined by retrospectively evaluating tumors in cats according to location, breed, sex, age range, and origin and comparing these with the literature.

Evaluation of the Antiparasitic, Antihepatotoxicity, and Antioxidant Efficacy of Quercetin and Chitosan, Either Alone or in Combination, against Infection Induced by Giardia lamblia in Male Rats.

Giardia lamblia (G. lamblia) is one of the most common protozoal infections and a key cause of malabsorption, some cases of mental developmental issues in children, and reduced body weight. The known antiparasitic medications, which are the standard drugs used for parasitic treatment, have several side effects and sometimes exhibit low efficacy. Therefore, the current study aimed to evaluate the treatment with quercetin (QC) or chitosan (CH), either alone or in combination, as possible alternative therapeutic agents that may alleviate the side effects of G. lamblia infections and restore the normal architecture of the intestinal muscles. They are investigated as alternatives to other routinely administered drugs that may gradually lose their efficacy due to human resistance to therapeutic agents. This study was carried out on 50 male albino rats that were divided into five groups with 10 rats in each group: the control group (Group I), the infected non-treated group (Group II), the infected group treated with QC (Group III), the infected treated group with CH (Group IV), and the infected group treated with a combination of QC and CH (Group V). The effect was first evaluated by counting the G. lamblia fecal cysts in the stool, examining histopathological sections of the intestine with the appearance of trophozoites in the infected group, and conducting a transmission electron microscopic examination of the tissues of the small intestine. Alterations in the biochemical parameters of liver and kidney function and the antioxidant enzymes in the liver tissues of SOD, CAT, and GSH, and non-enzymatic markers of lipid peroxidation (MDA) were evaluated. The results showed a significant decline in the number of parasites in the stool samples, with a marked elevation in the number of trophozoites in the intestinal sections of the infected non-treated group as compared to the infected treated groups. The last group, which was treated with a combination of QC and CH, showed the best results in terms of a decline in the infection rate of G. lamblia in stool samples, with a marked and clear improvement in the intestinal mucosa, regular muscles with normal enteric ganglions, and reduced rates of intestinal injuries caused by G. lamblia trophozoites. Both QC and CH had non-toxic effects on the biochemical parameters of the liver and kidneys, as well as pronounced antioxidant activities due to the elevation of SOD, CAT, and GSH in conjunction with a decline in the levels of MDA. A combination of QC and CH can be considered a potent antiparasitic, anti-hepatotoxic, and antioxidant therapeutic agent; it could constitute a promising alternative treatment agent against G. lamblia infection.

Comparative Tensile Properties and Collagen Patterns in Domestic Cat (Felis catus) and Dog (Canis lupus familiaris) Ovarian Cortical Tissues.

The importance of the ovarian extracellular environment and tissue rigidity on follicle survival and development has gained attention in recent years. Our laboratory has anecdotally observed differences in the rigidity of domestic cat and dog ovarian cortical tissues, which have been postulated to underlie the differences in in vitro culture responses between the species, wherein cat ovarian tissues display higher survival in extended incubation. Here, the tensile strengths of cat and dog ovarian cortical tissues were compared via micropipette aspiration. The underlying collagen patterns, including fiber length, thickness, alignment, curvature, branch points and end points, and overall tissue lacunary and high-density matrix (HDM) were quantified via picrosirius red staining and TWOMBLI analysis. Finally, we explored the potential of MMP (-1 and -9) and TIMP1 supplementation in modulating tissue rigidity, collagen structure, and follicle activation in vitro. No differences in stiffness were observed between cat or dog cortical tissues, or pre- versus post-pubertal status. Cat ovarian collagen was characterized by an increased number of branch points, thinner fibers, and lower HDM compared with dog ovarian collagen, and cat tissues exposed to MMP9 in vitro displayed a reduced Young's modulus. Yet, MMP exposure had a minor impact on follicle development in vitro in either species. This study contributes to our growing understanding of the interactions among the physical properties of the ovarian microenvironment, collagen patterns, and follicle development in vitro.

Feline Morbillivirus: Clinical Relevance of a Widespread Endemic Viral Infection of Cats.

Feline morbillivirus (FeMV) was first isolated in 2012 from stray cats in Hong Kong. It has been found in association with tubulointerstitial nephritis (TIN), the most common cause of feline chronic kidney disease (CKD). However, viral host spectrum and virus tropism go beyond the domestic cat and kidney tissues. The viral genetic diversity of FeMV is extensive, but it is not known if this is clinically relevant. Urine and kidney tissues have been widely tested in attempts to confirm associations between FeMV infection and renal disease, but samples from both healthy and sick cats can test positive and some cross-sectional studies have not found associations between FeMV infection and CKD. There is also evidence for acute kidney injury following infection with FeMV. The results of prevalence studies differ greatly depending on the population tested and methodologies used for detection, but worldwide distribution of FeMV has been shown. Experimental studies have confirmed previous field observations that higher viral loads are present in the urine compared to other tissues, and renal TIN lesions associated with FeMV antigen have been demonstrated, alongside virus lymphotropism and viraemia-associated lymphopenia. Longitudinal field studies have revealed persistent viral shedding in urine, although infection can be cleared spontaneously.

Transmission of Cytauxzoon felis by injection of Amblyomma americanum salivary glands.

Cytauxzoonosis is a life-threatening disease of cats, caused by the tick-borne piroplasmid hemoparasite, Cytauxzoon felis. Current experimental models for cytauxzoonosis rely on either tick transmission or direct injection of infected cat tissues. These models require researchers to directly work with infected ticks or use cats with acute cytauxzoonosis. To improve the feasibility and accessibility, there is a need to establish sharable resources among researchers. In related piroplasmid parasites, sporozoite-based inoculums are routinely produced from tick salivary glands, cryopreserved and distributed to other investigators and facilities. For these parasites, sporozoites have been the basis for vaccine development and in vitro cultivation, both of which remain lacking for C. felis research. If infectious sporozoites can be similarly isolated for C. felis, it would significantly broaden our capabilities to study this parasite. Aims of this study was to determine if C. felis sporozoites inoculums collected from the salivary glands of Amblyomma americanum ticks were capable of inducing cytauxzoonosis in naïve cats. A. americanum nymphs were acquisition-fed on a donor cat chronically infected with C. felis and allowed to molt to adults. Four groups of adult ticks (n = 50/group) were either stimulation-fed for 4 days on naïve cats or were heated at 37 °C for 4 days. After these treatments, salivary glands (SG) of each group of ticks were collected to create inoculums. Infectivity of these inoculums was then tested by subcutaneous injection into naïve cats. The two naïve cats used for stimulation feeding and as controls both developed cytauxzoonosis, indicating these groups of ticks were capable of producing infectious sporozoites. Of the 2 cats that were injected with SGs from the stimulation-fed ticks, one cat developed cytauxzoonosis and C. felis infection was confirmed by both light microscopy and PCR. The other cat did not develop cytauxzoonosis and only had equivocal evidence of infection. Neither cat injected with SGs from the heated ticks developed cytauxzoonosis. One of these cats had equivocal evidence of infection and one had no evidence of infection. This study validates the feasibility of collecting infectious sporozoites from C. felis-infected ticks that can be used to infect naïve cats. While this model requires further optimization, it has the potential to expand resources to study C. felis and further advance research in this field.

Effects of Graded Doses of Ethanolic Extract of Pausinystalia Yohimbe Stem Bark on Biochemical and Hematological Indices In the Kidneys of Female Wistar Rats

Pausinystalia yohimbe is a medicinal plant widely used as an aphrodisiac agent in Nigeria and other parts of West Africa, but little is known about its effect on renal function after chronic use. This study was designed to investigate the effect of ethanolic extract of Pausinystalia yohimbe stem bark on renal function parameters such as serum creatinine, urea, electrolyte, oxidative stress markers, and hematological parameters in female Wistar rats. Ethanolic extract of Pausinystalia yohimbe stem bark was administered orally to 3 groups of 5 female rats for 21 days as follows: group1 which served as control received distilled water while groups 2 and 3 received 400mg/kg and 800mg/kg body weight of the extract respectively. Thereafter the rats were sacrificed, and blood and kidney tissues were collected for biochemical analysis. The result showed that there were no significant changes in urea, creatinine, potassium, chloride, and bicarbonate levels while sodium level was significantly increased (p<0.05) when compared to the control. SOD and CAT tissue activities did not show any significant change (p<0.05) while there was a significant increase (p<0.05) in GSH and a significant reduction (p<0.05) in MDA. Also, there was no significant change (p<0.05) in WBC, PCV, and platelets, however, there was a significant decrease (p<0.05) in RBC and hemoglobin levels. The histopathology of the kidney showed that no significant changes were observed between treatment groups and control except for the 800 mg/kg body weight of the extract-treated group where there was mild multifocal vacuolar degeneration of some renal tubular epithelial cells. The result suggests that the chronic use of the ethanolic extract of Pausinystalia yohimbe stem bark protects the kidney against oxidative stress but adversely affects the functional capacities of the kidney and formation of erythropoietin in the stem cells and may also contribute to the increasing number of persons with high blood pressure.

Protective effect of cafestol against doxorubicin-induced cardiotoxicity in rats by activating the Nrf2 pathway.

Doxorubicin (DOX) is an efficient antineoplastic agent with a broad antitumor spectrum; however, doxorubicin-associated cardiotoxic adverse effect through oxidative damage and apoptosis limits its clinical application. Cafestol (Caf) is a naturally occurring diterpene in unfiltered coffee with unique antioxidant, antimutagenic, and anti-inflammatory activities by activating the Nrf2 pathway. The present study aimed to investigate the potential chemoprotective effect of cafestol on DOX-induced cardiotoxicity in rats. Wistar albino rats of both sexes were administered cafestol (5mg/kg/day) for 14 consecutive days by oral gavage alone or with doxorubicin which was injected as a single dose (15mg/kg intraperitoneally at day 14) to induce toxicity. The result showed that Caf significantly improved cardiac injury induced by doxorubicin, decreased serum levels of CK-MB, LDH, ALP, and ALT, and improved histopathological changes. In addition, cafestol significantly inhibited DOX-induced cardiac oxidative stress as seen in the reduced level of MDA and increased GSH, SOD, CAT, and Gpx-1 cardiac tissue levels; cafestol significantly enhanced Nrf2 gene and protein expression and promoted the expression of downstream antioxidant genes HO-1 and NQO-1 and downregulated Keap1 and NF-κB genes' expression; in addition, Caf significantly reduced inflammatory mediators, TNF-α, and IL-1β levels and inhibited cardiac apoptosis by modulating Bax and Casp 3 tissue levels and reduced TUNEL-positive cardiomyocytes. In conclusion, the present study confirmed that cafestol improved the cardiotoxic effects induced by doxorubicin through the regulation of apoptosis and oxidative stress response through the Nrf2 pathway; this study suggests that cafestol may serve as a potential adjuvant in chemotherapy to alleviate DOX-induced toxicities.

Feline microRNAome in ovary and testis: Exploration of in-silico miRNA-mRNA networks involved in gonadal function and cellular stress response.

The aim of the study was to perform the first in-depth analysis of miRNAs in ovarian and testicular tissues of the domestic cat, a critical biomedical model. Specifically, potential miRNA involvement was explored in gonadal function, testis development, and cellular stress response to preservation protocols. We performed miRNA-sequencing on 20 ovarian and 20 testicular samples from 15 cats, including different ages and tissue treatments. Using fresh tissues (n = 15), we confirmed gonadal expression of 183 miRNA precursors and discovered additional 52 novel feline candidate precursors. We integrated the mRNA data from our previous study on the same age and treatment groups to create in-silico miRNA-mRNA networks and their functional enrichment, which allows comprehensive exploration into possible miRNA functions in cat gonads. Clusters of miRNAs united by shared differentially expressed mRNA targets are potentially involved in testicular development and spermatogenesis. MicroRNAs could play a significant role in ovarian tissue response to stress from microwave-assisted dehydration, with smaller roles in cellular response to vitrification in both ovary and testis. This new list of miRNAs with potential function in cat gonads is a major step towards understanding the gonadal biology, as well as optimizing fertility preservation protocols.

Global proteomic profiling of multiple organs of cats (Felis catus) and proteome-transcriptome correlation during acute Toxoplasma gondii infection

BackgroundToxoplasma gondii is a protozoan parasite which can infect almost all warm-blooded animals and humans. Understanding the differential expression of proteins and transcripts associated with T. gondii infection in its definitive host (cat) may improve our knowledge of how the parasite manipulates the molecular microenvironment of its definitive host. The aim of this study was to explore the global proteomic alterations in the major organs of cats during acute T. gondii infection.MethodsiTRAQ-based quantitative proteomic profiling was performed on six organs (brain, liver, lung, spleen, heart and small intestine) of cats on day 7 post-infection by cysts of T. gondii PRU strain (Genotype II). Mascot software was used to conduct the student’s t-test. Proteins with P values < 0.05 and fold change > 1.2 or < 0.83 were considered as differentially expressed proteins (DEPs).ResultsA total of 32,657 proteins were identified in the six organs, including 2556 DEPs; of which 1325 were up-regulated and 1231 were down-regulated. The brain, liver, lung, spleen, heart and small intestine exhibited 125 DEPs, 463 DEPs, 255 DEPs, 283 DEPs, 855 DEPs and 575 DEPs, respectively. Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of all proteins and DEPs in all organs showed that many proteins were enriched in binding, cell part, cell growth and death, signal transduction, translation, sorting and degradation, extracellular matrix remodeling, tryptophan catabolism, and immune system. Correlations between differentially expressed proteins and transcripts were detected in the liver (n = 19), small intestine (n = 17), heart (n = 9), lung (n = 9) and spleen (n = 3).ConclusionsThe present study identified 2556 DEPs in six cat tissues on day 7 after infection by T. gondii PRU strain, and functional enrichment analyses showed that these DEPs were associated with various cellular and metabolic processes. These findings provide a solid base for further in-depth investigation of the complex proteotranscriptomic reprogramming that mediates the dynamic interplays between T. gondii and the different feline tissues.

ANTIOXIDANTS AND ANTI-INFLAMMATION POTENTIALOF AMARANTHUS VIRIDIS LINN AGAINST 3-NP-INDUCED HUNTINGTONS DISEASE IN RATS

Huntingtons disease (HD) is an autosomal dominant neurodegenerative disease. Accordingly, 3-nitropropionic acid (3-NP) has been found to effectively produce HD-like symptoms. Amaranthus viridis Linn (HAEAV), popularly known in Chauraiya in Hindi, may act as a neuroprotective agent in vitro andin vivo. We evaluated the hypothesis that the hydro-ethanolic extract of Amaranthus viridis Linn could prevent behavioral and oxidative alterations induced by 3-NP in rats. 30 albino Wistar female rats were divided into 5 groups: (1) control, (2) HAEAV(400 mg/kg), (3) 3-NP, (4) HAEAV(200 mg/kg) + 3-NP, and (5) HAEAV(400 mg/kg) + 3-NP.Animals in groups 3, 4, and 5 received 15 mg/kg 3-NP daily from days 8–14. At day 14, parameters of locomotor activity and biochemical evaluations were performed. Indeed, rats treated with 3-NP showed decreased locomotor activity compared to controls. Additionally, 3-NP increased levels of reactive oxygen species and lipid peroxidation and decreased ratio of CAT, TT, and GSHactivityinbrain tissues. Our results suggest that rats pretreated with HAEAVprior to 3-NP treatment showed neuroprotective effects when compared to 3-NP treated controls, which may be due to its antioxidant properties.

Novel Formaldehyde-Free Embalming Fluid Formulation for Long-term Preservation of Cadavers for Anatomy Teaching

The dissection of mammalian cadavers enables veterinary students to appreciate the three-dimensional relationships of these specimens. Chemically fixed cadavers are generally used for dissections owing to the impracticality of using fresh specimens in most teaching facilities. The aim of this study was to evaluate a novel embalming fluid formulation comprising 25% ethanol, 20% polyethylene glycol 400, 0.1% chloroxylenol, and 10% sodium nitrate made up to 100% with tap water to fix a series of domestic mammals for anatomical dissection. The embalmed cadavers (two cats, two dogs, two goats, and two sheep) were periodically evaluated over a 6-month period. At 1, 10, and 20 weeks of the dissection program, the cadavers were colorimetrically measured and the texture profiles, including hardness, adhesiveness, and deformation, were examined. In addition, tissue samples of the skeletal muscle, liver, lung, and intestine were collected and microbiologically analyzed at various time intervals. The embalmed cadavers closely resembled their fresh counterparts. There was a negligible difference in the objective and subjective parameters, with a gradual increase in the hardness and adhesiveness of the muscle samples with time. No microbiological growth was detected in the tissue samples obtained from the embalmed specimens, except in the colon tissue from one cat and lung tissue from one sheep. These findings demonstrated the successful preservation of cadavers in the novel embalming formulation for a period of 6 months. The subjective evaluations during dissection were harmonious with the objective assessments of the embalmed cadaver.

Bacteriological assessment and multiplex-PCR test for the detection of meat adulteration of different animal species

Meat samples of various animal species have been obtained from Giza Governorate's butcher shops, common retail markets, veterinary faculties, Zoo and hospitals. Physical, bacteriological, and molecular analysis was carried out on the meat samples. Physical examination showed that typical and untypical meat differed. Bacteriological examination showed the highest TCC was found in horse meat while the least was in goat meat. The total count of S. aureus was the highest in donkey and dog whilst the least in pork meat. As for E.coli, donkey meat was the highest while buffalo and mutton meat were the lowest. The highest total Listeria monocytogenes and Salmonella Species count were in horse, donkey, rat and dog meat but zero in the other species examined. Multiplex-PCR targeting partial-length of cytochrome b (cyt b) gene of mitochondrial DNA (mtDNA) was used for the discovery of adulteration of beef meat with chicken, pork, dog, cat and rat tissue. It showed high specificity in differentiating the six animal species meat. The study points out the importance of taking serious steps to control species meat adulteration that may lead to transmission of severe foodborne diseases and more studies need to be implemented to apply new and easy meat adulteration detection protocols.

Fixation and Comparative Histologic Evaluation of Cat and Dog Tissues using Different Fixatives

Tespit işlemi, hücre ve doku komponentlerinin ölüm sonrasında morfolojik özelliklerinin canlıdaki durumuna en yakın şekilde sabitleyip, histolojik olarak incelenmesine olanak tanır. Tespit işleminde kullanılan kimyasal ajanlara fik-satif denir. Yirminci yüzyıldan günümüze kadar rutin doku tespit işleminde formaldehit çözeltisi kullanılmaktadır. Her fiksatif doku tespit işlemi süresince doku histomorfolojisinin incelenmesi adına avantaj ve dezavantajlara sahiptir. Bu nedenle tespit işlemi için amaca yönelik doğru fiksatif ile çalışılması gerekir. Bu çalışmada hedef, 3 farklı fiksatif ile hazırlanan 4 çözeltinin, diğer faktörler optimum seviyede tutularak, doku tespit işlemi sürecinde nasıl etkilere sahip olduklarını belirlemek ve tespit özelliklerine göre en ideal kullanım amaçlarını ortaya çıkarmaktı. Bu amaçla, çalışmada doku tespit işlemi sırasında fiksatiflerin dezavantajlarından etkilenen ve hücre morfolojisinin incelenmesinde zorluklarla karşılaşılan dalak ve böbrek dokuları üzerinde çalışıldı. Yaklaşık 0.5 cm kalınlığındaki doku örnekleri hazırlanan %3.7`lik, %10`luk formaldehit ve Hollande çözeltilerinde 16 saat, Carnoy çözeltisinde ise 4 saat süre ile tespit edildi. Ru-tin doku takip işlemlerinden geçirildikten sonra alınan doku kesitleri H&amp;E ile boyandı. Bu dokuların histomorfolojik ince-lemeleri yapıldığında hücre sitoplazma boyanması için en uygun fiksatifin %3.7`lik formaldehit çözeltisi olduğu, hücre çekirdek ve çekirdekçiklerinin morfolojisini ortaya koymada ise Carnoy ve Hollande çözeltilerin kullanımlarının ideal olduğu, ancak Carnoy çözeltisinin eritrositlerde ileri düzeyde lizise yol açtığı gözlendi. Sonuç olarak, doku tespit işle-minde %3.7`lik formaldehit çözeltisinin kullanımı ideal bulunurken, Carnoy ve Hollande çözeltilerinin ise hücre çekirdek-lerindeki histomorfolojik değişikliklerin detaylı incelenmesini gerektiren hastalıklarda etkili bir kullanım oluşturacakları ön görüldü.

Molecular characterization of free fatty acid receptors FFAR2 and FFAR3 in the domestic cat.

G protein‐coupled receptors 41 and 43 were identified and characterized as free fatty acid receptors (FFAR) 3 and 2, respectively. FFAR2 and FFAR3 mediate short‐chain fatty acids (SCFAs) as signalling molecules. The present study aimed to give molecular characterization of FFAR2 and FFAR3 in the domestic cat. High homology with that in other mammals was revealed by cDNA cloning of cat FFAR2 FFAR3. We analyzed the tissue distribution of cat FFAR2 and FFAR3 mRNA using quantitative polymerase chain reaction. The inhibition of intracellular cAMP concentrations was observed in cells transfected with cat FFAR2 or FFAR3 and treated with SCFAs. The activation of nuclear factor of activated T cells‐luciferase reporter was only observed in cat FFAR2 transfected cells but not in FFAR3. Split luciferase assay (NanoLuc Binary Technology; NanoBiT) for FFAR2 or FFAR3 and Arrestin‐3/β‐arrestin‐2 revealed acetate‐/propionate‐induced recruitment to cat FFAR2 or FFAR3 in CHO‐K1 cells. Our results indicate that FFAR2 and FFAR3 are functional receptor proteins that are expressed in cat tissues and show differential distribution patterns.

Pharmacokinetics and distribution of 2-hydroxypropyl-β-cyclodextrin following a single intrathecal dose to cats.

2‐Hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD) is an experimental therapy for Niemann‐Pick disease type C (NPC) that reduced neuronal cholesterol and ganglioside storage, reduced Purkinje cell death, and increased lifespan in npc1−/− mice and NPC1 cats. In this study, tissue distribution was investigated in normal cats that received a single 120‐mg dose of [14C]‐HP‐β‐CD (approximately 200 μCi/cat) via the cerebellomedullary cistern (CBMC) and lumbar cistern. One cat was euthanized at each of various time points up to 24 hours postdose for subsequent processing and quantitative whole‐body autoradiographic analysis. HP‐β‐CD‐derived radioactivity absorbed from the CBMC was widely distributed to cat tissues; most tissues were observed to have reached their highest concentration at 1 hour postdose. HP‐β‐CD‐derived radioactivity penetrated into the deeper parts of the central nervous system with the highest concentration at 4 hours (403 μg Eq/g or 0.28 mM) and remained high (49.7 μg Eq/g or 0.03 mM) at 24 hours. The relatively long half‐life (11‐30 hours) in cerebral ventricles and the subarachnoid space surrounding the brain and spinal cord might contribute to the efficacy of HP‐β‐CD in NPC1 cats. Other tissues with high concentrations of radioactivity were nasal turbinates, pituitary gland, and urinary bladder, while relatively low concentrations were observed in blood and bile.

Tissue distribution and characterization of feline cytochrome P450 genes related to polychlorinated biphenyl exposure

Cats have been known to be extremely sensitive to chemical exposures. To understand these model species' sensitivity to chemicals and their toxicities, the expression profiles of xenobiotic-metabolizing enzymes should be studied. Unfortunately, the characterization of cytochrome P450 (CYP), the dominant enzyme in phase I metabolism, in cats has not extensively been studied. Polychlorinated biphenyls (PCBs) are known as CYP inducers in animals, but the information regarding the PCB-induced CYP expression in cats is limited. Therefore, in the present study, we aimed to elucidate the mRNA expression of the CYP1–CYP3 families in the cat tissues and to investigate the CYP mRNA expression related to PCB exposure. In cats, the greatest abundance of CYP1–CYP3 (CYP1A2, CYP2A13, CYP2C41, CYP2D6, CYP2E1, CYP2E2, CYP2F2, CYP2F5, CYP2J2, CYP2U1, and CYP3A132) was expressed in the liver, but some extrahepatic isozymes were found in the kidney (CYP1A1), heart (CYP1B1), lung (CYP2B11 and CYP2S1) and small intestine (CYP3A131). In cats, CYP1A1, CYP1A2 and CYP1B1 were significantly upregulated in the liver as well as in several tissues exposed to PCBs, indicating that these CYPs were distinctly induced by PCBs. The strong correlations between 3,3′,4,4′-tetrachlorobiphenyl (CB77) and CYP1A1 and CYP1B1 mRNA expressions were noted, demonstrating that CB77 could be a potent CYP1 inducer. In addition, these CYP isoforms could play an essential role in the PCBs biotransformation, particularly 3–4 Cl-PCBs, because a high hydroxylated metabolite level of 3–4 Cl-OH-PCBs was observed in the liver.