Conventional Rats Research Articles

Structural and Functional Differences in Small Intestinal and Fecal Microbiota: 16S rRNA Gene Investigation in Rats.

To compare the differences in floral composition and functions between the two types of microbiota, ileal contents and feces were collected from Sprague Dawley (SD) rats fed in a conventional or specific-pathogen free (SPF) environment and rats fed a high-fat diet (HFD), and the V3-V4 region of the 16S ribosomal ribonucleic acid (rRNA) gene in these rats was then amplified and sequenced. Compared with feces, about 60% of the bacterial genera in the ileum were exclusive, with low abundance (operational taxonomic units (OTUs) < 1000). Of bacteria shared between the ileum and feces, a few genera were highly abundant (dominant), whereas most had low abundance (less dominant). The dominant bacteria differed between the ileum and feces. Ileal bacteria showed greater β-diversity, and the distance between in-group samples was nearer than that between paired ileum-feces samples. Moreover, the ileum shared various biomarkers and functions with feces (p < 0.05). The HFD and SPF conditions had a profound influence on α-diversity and abundance but not on the exclusive/shared features or β-diversity of samples. The present findings suggested that, under conventional circumstances, fecal bacteria can represent approximately 40% of the low abundant ileal bacterial genera and that dominant fecal bacteria failed to represent the ileal dominant flora. Moreover, fecal flora diversity does not reflect β-diversity in the ileum.

Factors Affecting Endogenous Oxalate Synthesis and Its Excretion in Feces and Urine in Rats

It has been observed that the feces as well as urine of rats fed diets supplemented with 3% glycine and 5.2% hydroxyproline contain unexpectedly high amounts of endogenously formed oxalate. That intestinal microorganisms do not synthesize significant amounts of oxalate was indicated by the findings that oral tetracycline had no effect on oxalate excretion and that germ-free rats excreted more oxalate than conventional rats. Since little intraperitoneally injected [14C]oxalate appeared in the feces, and rat intestinal mucosa homogenates were found to produce oxalate from a variety of precursors of which glyoxylic acid was by far the most important, it is probable that the intestinal mucosa may be an important source of fecal oxalate observed in these studies. Ninety percent of weanling rats fed complete diets supplemented with glycine and hydroxyproline developed urinary stones in 38 days. It has been concluded that in the treatment of patients with histories of calcium oxalate urolithiasis, more concern than is commonly shown should be directed towards the feeding of diets high in precursors of endogenous oxalate synthesis.oxalate hydroxyproline calculi

Metabolic Fate and Expectation of Health Benefits of [U-&lt;sup&gt;14&lt;/sup&gt;C]-Sucrose Inhibited from Digestion Using &lt;i&gt;Morus alba&lt;/i&gt; Leaf Extract

Morus alba leaf extract (MLE), a strong inhibitor of sucrase, suppresses blood glucose elevation following sucrose ingestion. To investigate that sucrose inhibited from digestion using MLE is utilized through gut microbiota, [U-14C]-sucrose solutions with or without MLE were administered orally to conventional and antibiotic-treated rats, and the excretion of 14CO2 and H2 produced by gut microbiota was measured for 24 h. After an administration of [U-14C]-sucrose to conventional rats, the unit excreted 14CO2 peaked at 4 h, and the cumulative 14CO2 excreted over 24 h was approximately 60% of the radioactivity administered. No H2 was excreted. Following an administration of [U-14C]-sucrose and MLE in conventional rats, the unit excreted 14CO2 peaked later, at 8 h, and was significantly lower (p<0.05). The cumulative 14CO2 excreted over 24 h was equal in both groups, although there was a time lag of 2-3 h in rats given [U-14C]-sucrose and MLE. The amount of H2 excreted by these rats peaked 8 h after administration. Following the administration of [U-14C]-sucrose and MLE to antibiotic-treated rats, the unit excreted 14CO2 peaked lower, and the cumulative 14CO2 excretion over 24 h was approximately 40%. In this group, H2 was minimally excreted. H2 and 14CO2 produced by gut microbiota were excreted simultaneously. In conclusion, sucrose inhibited from digestion using MLE was fermented spontaneously by gut microbiota and was not excreted into feces. In addition, it confirmed that H2 excretion could be used directly to indicate the degree of fermentation of nondigestible carbohydrates.

Sex-dependent impact of microbiota status on cerebral μ-opioid receptor density in fischer rats.

μ‐opioid receptors (MOPr) play a critical role in social play, reward and pain, in a sex‐ and age‐dependent manner. There is evidence to suggest that sex and age differences in brain MOPr density may be responsible for this variability; however, little is known about the factors driving these differences in cerebral MOPr density. Emerging evidence highlights gut microbiota's critical influence and its bidirectional interaction with the brain on neurodevelopment. Therefore, we aimed to determine the impact of gut microbiota on MOPr density in male and female brains at different developmental stages. Quantitative [3H]DAMGO autoradiographic binding was carried out in the forebrain of male and female conventional (CON) and germ‐free (GF) rats at postnatal days (PND) 8, 22 and 116–150. Significant ‘microbiota status X sex’, ‘age X brain region’ interactions and microbiota status‐ and age‐dependent effects on MOPr binding were uncovered. Microbiota status influenced MOPr levels in males but not females, with higher MOPr levels observed in GF versus CON rats overall regions and age groups. In contrast, no overall sex differences were observed in GF or CON rats. Interestingly, within‐age planned comparison analysis conducted in frontal cortical and brain regions associated with reward revealed that this microbiota effect was restricted only to PND22 rats. Thus, this pilot study uncovers the critical sex‐dependent role of gut microbiota in regulating cerebral MOPr density, which is restricted to the sensitive developmental period of weaning. This may have implications in understanding the importance of microbiota during early development on opioid signalling and associated behaviours.

Reconstitution of the host holobiont in germ-free born male rats acutely increases bone growth and affects marrow cellular content.

Integration of microbiota in a host begins at birth and progresses during adolescence, forming a multidirectional system of physiological interactions. Here, we present an instantaneous effect of natural, bacterial gut colonization on the acceleration of longitudinal and radial bone growth in germ-free born, 7-wk-old male rats. Changes in bone mass and structure were analyzed after 10 days following the onset of colonization through cohousing with conventional rats and revealed unprecedented acceleration of bone accrual in cortical and trabecular compartments, increased bone tissue mineral density, improved proliferation and hypertrophy of growth plate chondrocytes, bone lengthening, and preferential deposition of periosteal bone in the tibia diaphysis. In addition, the number of small in size adipocytes increased, whereas the number of megakaryocytes decreased, in the bone marrow of conventionalized germ-free rats indicating that not only bone mass but also bone marrow environment is under control of gut microbiota signaling. The changes in bone status paralleled with a positive shift in microbiota composition toward short-chain fatty acids (SCFA)-producing microbes and a considerable increase in cecal SCFA concentrations, specifically butyrate. Furthermore, reconstitution of the host holobiont increased hepatic expression of IGF-1 and its circulating levels. Elevated serum levels of 25-hydroxy vitamin D and alkaline phosphatase pointed toward an active process of bone formation. The acute stimulatory effect on bone growth occurred independently of body mass increase. Overall, the presented model of conventionalized germ-free rats could be used to study microbiota-based therapeutics for combatting dysbiosis-related bone disorders.

A novel PCOS rat model and an evaluation of its reproductive, metabolic, and behavioral phenotypes.

BackgroundAlthough animal models of PCOS have been used in many studies, none of them can reproduce both the reproductive and metabolic phenotypes of PCOS. In addition, behavioral parameters have not been evaluated in PCOS animal models.PurposeWe tried to produce an improved rat model of PCOS, and the reproductive, metabolic, and behavioral phenotypes of the model rats were evaluated.MethodsFemale rats were implanted with silicon tubes containing oil‐dissolved dihydrotestosterone (Oil‐DHT) as a new PCOS model. Their phenotypes were compared with those of conventional PCOS model rats (DHT), into which tubes containing crystalline DHT were implanted, and non‐DHT‐treated rats (control).ResultsBoth the Oil‐DHT and DHT rats showed greater body weight gain, food intake, and fat depot weight than the control rats. Furthermore, these groups showed fewer estrous stages and increased numbers of cystic follicles. The DHT rats exhibited lower ovarian and uterine weights than the control rats, whereas no such changes were observed in the Oil‐DHT rats. The Oil‐DHT and DHT rats showed less locomotor activity in the light phase than the control rats.ConclusionsOur proposed PCOS model reproduced both the reproductive and metabolic phenotypes of PCOS and may have potential for PCOS research.

Protective effect of three developed gel formulations: Chitosan, Chitosan with Taurine and Chitosan with Dexpanthenol, on the acute overdose of Diclofenac sodium in preclinical studies

Objectives: To investigate the tissue-protective effects of three gel formulations (chitosan, chitosan with taurine or chitosan with dexpanthenol) as active substances against an acute overdose of diclofenac sodium. Methods: White outbred conventional male rats were allocated to five experimental groups: the first is an intact group that did not receive any drug, the second group is a control group that received 50mg/kg of diclofenac sodium once orally, the third, fourth and fifth groups are an experimental group that received our studied drugs at a dose of 0.16ml/100mg b.w. once orally 1 hr. before diclofenac sodium, the third group received chitosan-based gel 1%, the fourth group received chitosan-based gel 1% with 4% taurine and the fifth group chitosan-based gel 1% with 0.43% dexpanthenol. Blood samples were taken for biochemical, hematological and blood coagulation system tests on day 7th after administration of diclofenac sodium. Results: An acute overdose of diclofenac sodium caused marked extensive tissue necrosis in the liver, bleeding in the gastrointestinal tract and inflammatory process, these marks were evidenced by different changes in the test of the blood samples. Significantly 73.6% of the blood indicators were improved by the administration of chitosan-based gel 1% with 0.43% dexpanthenol, while 57.8% were improved by chitosan-based gel 1% with 4% taurine and 68.4% by chitosan-based gel 1%. Conclusion: Chitosan-based gel 1% with dexpanthenol 0.43% can help in mitigating hepatic injury, gastrointestinal bleeding, and systemic and local intestinal inflammation caused by an acute overdose of diclofenac sodium.

Comparative evaluation of chitosan-based multifunctional wound dressings: a multistage randomised controlled experimental trial

Background. Wounds of various aetiology are among the most frequent traumatic injuries. A prospective route to improve treatment of this nosology is the development of novel or advancement of the already on-stage dressing materials.Objectives. A comparative experimental assay of novel chitosan-based wound dressings in the healing of soft tissue wounds of different genesis using ultrasound to control biodegradation of the developed dosage form.Methods. Soft tissue wounds were modelled in experimental animals, conventional and lineage male rats, 275 (± 25) g body weight, and male rabbits, 2,900 (± 150) g weight, using a proprietary methodology (Patent on invention RU No. 2703709 dated 23 August, 2018).Two wound dressing samples selected as most promising and applicable in large-volume soft tissue aseptic wounds were tested in the final step of experiment. Ultrasound imaging of the model wound area during the sample material biodegradation was used to control the wound process in more detail. At all steps of experiment, animal models were handled in compliance with GOST 33044-2014 “Principles of Good Laboratory Practice”.Histomorphological assays were carried out with common protocols. Variation statistics was used for the data analysis, including the mean (M) and standard mean error (± m) estimation. The level of statistical significance was p &lt; 0.05.Results. The animal assays and comprehensive evaluation of the obtained data revealed a high healing efficacy of chitosan-based wound coatings. The analyses of wound dressing samples have confirmed their predesigned properties: scaffold stability, capillarity, biodegradability and matrix capacities for the carried drug delivery.Additionally, ultrasound was proved effective to estimate dynamics of the coated wound healing and biopolymer biodegradation processes.Conclusion. The developed chitosan-based wound dressings exhibited efficacy in an experimental model of the soft tissues wound process.The use of ultrasound to study dynamics of the wound process and coating biodegradation provided an adequate congruence between the imaging and tissue histomorphology data, as well as the structure and properties of coating material.

Gut Microbiota Accelerates Bone Growth and Marrow Adiposity of the Adolescent Gnotobiotic Rat

Skeletal growth and bone homeostasis are significant holobiome components strongly tied to the gut microbiota. We aimed to explore the requirement of gut microbiome for skeletal maturation in an adolescent organism. For our approach, we co-housed young (7-week-old) germ-free (GF) rats with conventional rats of the same age, sex (male), and strain (Sprague Dawley) for 10 days to naturally conventionalize GF (GFC) rats with the gut microbiota by coprophagy. Bone morphometry by micro-CT scanning and histological staining revealed accelerated longitudinal and radial bone growth in GFC rats when compared to GF rats. Changes in bone mass and structure for GFC rats encompassed an increase of bone accrual in cortical and trabecular compartments, greater tissue mineral density, improved proliferation and hypertrophy of growth plate chondrocytes, bone lengthening, and preferential deposition of periosteal bone in the tibia diaphysis. Analysis of bone marrow at the tibia midshaft depicted more adipocyte number, greater adipocyte density, and altered cell size distribution to favor small adipocytes, but reduced megakaryocytes, in GFC rats. Interestingly, putative effector genes responsible for bone mass accumulation were found to be comparable between GF and GFC rats, which shifted our focus onto systemic host and microbial regulatory factors. Assessment of serum markers indicated that the active bone formation could be due to elevated levels of 25-hydroxy vitamin D and alkaline phosphatase. Importantly, 16S ribosomal RNA gene sequencing demonstrated that the prominent bacterial colonizers were Clostridiaceae and Clostridium members, which are potent short chain fatty acid (SCFA) producers. 1H-NMR metabolomics in the cecal contents showed a dramatic increase of SCFA, specifically butyrate, following bacterial colonization. In relation with the literature, our observation of increased hepatic insulin-like growth factor-1 (IGF-1) expression and systemic IGF-1 levels suggest that butyrate promotes bone growth through the somatotropic axis. Collectively, our study demonstrates that gut microbiota can deliver signals to the skeleton for accelerating bone expansion and accumulating marrow fat.

Dietary switch to Western diet induces hypothalamic adaptation associated with gut microbiota dysbiosis in rats.

Early hyperphagia and hypothalamic inflammation encountered after Western diet (WD) are linked to rodent propensity to obesity. Inflammation in several brain structures has been associated with gut dysbiosis. Since gut microbiota is highly sensitive to dietary changes, we hypothesised that immediate gut microbiota adaptation to WD in rats is involved in inflammation-related hypothalamic modifications. We evaluated short-term impact of WD consumption (2 h, 1, 2 and 4 days) on hypothalamic metabolome and caecal microbiota composition and metabolome. Data integration analyses were performed to uncover potential relationships among these three datasets. Finally, changes in hypothalamic gene expression in absence of gut microbiota were evaluated in germ-free rats fed WD for 2 days. WD quickly and profoundly affected the levels of several hypothalamic metabolites, especially oxidative stress markers. In parallel, WD consumption reduced caecal microbiota diversity, modified its composition towards pro-inflammatory profile and changed caecal metabolome. Data integration identified strong correlations between gut microbiota sub-networks, unidentified caecal metabolites and hypothalamic oxidative stress metabolites. Germ-free rats displayed reduced energy intake and no changes in redox homoeostasis machinery expression or pro-inflammatory cytokines after 2 days of WD, in contrast to conventional rats, which exhibited increased SOD2, GLRX and IL-6 mRNA levels. A potentially pro-inflammatory gut microbiota and an early hypothalamic oxidative stress appear shortly after WD introduction. Tripartite data integration highlighted putative links between gut microbiota sub-networks and hypothalamic oxidative stress. Together with the absence of hypothalamic modifications in germ-free rats, this strongly suggests the involvement of the microbiota-hypothalamus axis in rat adaptation to WD introduction and in energy homoeostasis regulation.

The influence of anilinopyrimidine and carbamate derivatives on the rat redox status

Introduction. Oxidative stress can occur as the response to the toxic effects of pesticides. A study of the effect of two generic pesticides on the enzymes of the antioxidant defense system of warm-blooded animals was carried out within the framework of chronic food exposure. Material and Methods. 90 conventional male rats were kept in the vivarium of the Federal scientific center of hygiene named after F.F. Erisman for a year. Test objects including fungicide of the anilinopyrimidines class (compound A) and insecticide from of the carbamates class (compound B) were introduced into animal feed at doses of 0; 2; 20; 120 and 240 mg/kg body weight and 0; 2.5; 5 and 20 mg/kg body weight, respectively. Doses corresponded to the ranges found in the reports by the Joint Meeting of the FAO/WHO Meeting on Pesticide Residues for the original compounds in chronic toxicity studies. The effect of the studied compounds on the general antioxidant status (the activity of enzymes: superoxide dismutase (SOD), glutathione peroxidase (GPO), glutathione reductase (GR) and catalase (CAT)) was assessed at 3, 6, 9, and 12 months. Results. The test objects caused statistically significant changes in enzyme activity as early as at 3 months of the treatment, compared with animals of the concurrent negative control. For the compound A: a statistically significant dose-dependent increase in the activity of GR (Rho = 0.381, p = 0.017) and GAP (Rho = 0.355, p = 0.024), but not SOD and CAT, was recorded at 12 months. The compound B caused a statistically significant dose-dependent increase in SOD activity at 9 and 12 months (Rho = 0.491, p = 0.006; Rho = 0.506, p = 0.003) Conclusion. These observations indicate that compounds A and B could promote lipid peroxidation. Oxidative burst was registered in response to the influence of the compound B, which may have been caused by apoptosis of T-lymphocytes.

Oxyberberine, an absorbed metabolite of berberine, possess superior hypoglycemic effect via regulating the PI3K/Akt and Nrf2 signaling pathways

Berberine (BBR) is a promising anti-diabetic isoquinoline alkaloid from Rhizoma coptidis, while its bioavailability was extremely low. Here, the existing form and pharmacokinetics of BBR were comparatively characterized in conventional and antibiotic-induced pseudo germ-free (PGF) rats. Furthermore, we comparatively investigated the antidiabetic effect and potential mechanism of BBR and its intestinal oxidative metabolite oxyberberine (OBB) in STZ-induced diabetic rats. Results showed that BBR and OBB existed mainly as protein-bound form in blood, while protein-bound OBB was significantly depleted in PGF rats. Treatment with OBB and BBR effectively decreased clinical symptoms of diabetic rats, reduced blood glucose level, ameliorated the pancreatic damage, and mitigated oxidative stress and inflammatory markers. However, the anti-diabetes effect of BBR was obviously compromised by antibiotics. In addition, OBB exerted superior anti-diabetes effect to BBR of the same dose, significantly up-regulated the mRNA expression of Nrf2 signaling pathway and substantially promoted the pancreatic levels of PI3K/Akt signaling pathway. In conclusion, BBR and its absorbed oxidative metabolite OBB were mainly presented and transported in the protein-bound form in vivo. The gut microbiota may play an important role in the anti-diabetes effect of BBR through transforming itself into the superior hypoglycemic metabolite OBB. OBB possessed favorable hypoglycemic and pancreatic β-cells protective effects, which may stand a huge potential to be further developed into a promising anti-diabetes candidate.

Region-specific sex modulation of central oxytocin receptor by gut microbiota: An ontogenic study.

Oxytocin (OT) is a developmentally important neuropeptide recognized to play a dominant role in social functioning and stress-related behaviors, in a sex-dependent manner. Nonetheless, the underlining factors driving OT and OT receptor (OTR) early brain development remain unclear. Recent evidence highlight the critical influence of gut microbiota and its bidirectional interaction with the brain on neurodevelopment via the gut microbiota-brain axis. Therefore, we aimed to determine the impact of gut microbiota on the OTR system of the rat brain at different developmental stages in a pilot study. Quantitative OTR [125 I]-OVTA autoradiographic binding was carried out in the forebrain of male and female conventional (CON) and germ-free (GF) rats at postnatal days (PND) 8, 22, and 116-150. OTR binding was also assessed in the eyes of PND 1 and PND 4 GF female rats. Significant "microbiota × sex × region" interaction and age-dependent effects on OTR binding were demonstrated. Microbiota status influenced OTR levels in males but not females with higher levels of OTR observed in GF versus CON rats in the cingulate, prelimbic, and lateral/medial/ventral orbital cortex, and septum across all age groups, while sex differences were observed in GF, but not in CON rats. Interestingly, OTRs present in the eyes of CON rats were abolished in GF rats. This is the first study to uncover a sex-specific role of gut microbiota on the central OTR system, which may have implications in understanding the developmental neuroadaptations critical for behavioral regulation and the etiology of certain neurodevelopmental disorders.

Effects of Cerium Oxide Nanoparticles on Biochemical Parameters and Histopathological Changes in Lead-Intoxicated Rats

Background: The present study was conducted to investigate the potential protective effect of cerium oxide nanoparticles (CeNPs) against lead acetate-induced toxicity. Materials and Methods: In this study, 30 adult male Wistar rats were randomly divided into three groups and treated simultaneously, except for the normal control, for 5 weeks with lead acetate in drinking water (1000 mg/L). Control rats and negative control rats received saline intraperitoneally. At the same time, the third group was treated with intraperitoneal injections of CeNPs at the dose of 0.5 mg/kg 1 week before lead administration, and continued with its administration. Finally, serum was obtained by the conventional methods and rats were sacrificed to obtain liver, heart, testis, and kidney tissue for histopathological examinations. Results: The lead-treated group showed significant increases in blood urea nitrogen (BUN), serum creatinine, serum aspartate aminotransferase (AST), serum alanine aminotransferase (ALT), and malondialdehyde (MDA) levels (P&lt;0.01). Lead-intoxicated rats treated with CeNPs showed a significant decrease in serum lactate dehydrogenase (LDH), AST, and ALT levels compared to the untreated negative control group (P&lt;0.01). The histopathological examination of liver and kidney tissues showed signs of lead-induced injuries, necrotic hepatocytes, and glomerulosclerosis. The CeNPs-treated group showed noticeable reductions in histopathological signs of lead-induced injuries. Lipid peroxidation levels were also lower in CeNPs-treated rats than negative controls (P&lt;0.05). Conclusion: The current experimental study proved the protective effects of CeNPs in rats exposed to chronic lead-induced toxicity; however, more experiments are required to evaluate the possible side effects and interactions.

Abstract P112: Elevated Blood Pressure In Conventionalized Germ-free Rats Is Coupled With Upregulation Of Kynurenic Pathway Metabolites And Central Immune Responses

Background: Recent evidence supports that metabolic dysfunction underlies hypertension. Injection of kynurenate, a metabolite of tryptophan pathway, into the paraventricular nucleus of the hypothalamus (PVN) lowers blood pressure (BP). Intestinal absorption and metabolism of tryptophan are impacted by gut microbiota. Since gut-brain axis contributes to gut dysbiosis-inducd hypertension, we hypothesized that gut microbiota modulates the levels of kynurenic pathway metabolites that have central impact on BP regulation. Methods: We, for the first time, used 7 weeks old male Germ-free (GF) Spague Dawley (SD) rats (n=5) and GF rats co-housed with conventional SD rats for 10 days (GFC) (n=6). BP was measured by tail-cuff. Serum metabolites were quantified by 6495 triple quandrople mass spectrometryand data was normalized using isotoplic labelled compounds. The nucleus of the solitary tract (NTS), the principal sensory nucleus for peripheral changes, and the PVN, a relay center projecting sympathetic output based on the integrated afferent inputs from brain regions including NTS, were analyzed by microarray hybridization for mRNA expression. Results: Compared to the GF rats, GFC rats had significantly higher systolic (139 mmHg vs 115 mmHg, p &lt;0.05), diastolic BP (96 mmHg vs 79 mmHg, p &lt;0.05), and serum levels of kynurenic acid (-9.76 vs -10.21, p &lt;0.05) and 3-hydroxy kynurenine (-6.49 vs -7.34, p &lt;0.01). Coupled with these increases in kynurenic pathway metabolites, microarray analyses demonstrated increased immune responses (e.g. Cd74, Il1b, Cxcl1, Mmp14 ) in the PVN (gene ontology analysis, p &lt;0.001) and increased cell differentiation and synaptic plasticity (e.g. Sox11, Tp53, Cdk6, Hoxb4, Foxo4, Cyr61 ) in the NTS (gene ontology analysis, p &lt;0.01). Conclusion: Colonization of gut microbiota in GF rats induced increased cell differentiation and synaptic plasticity in the NTS and immune responses in the PVN, indicating the restructured sensory neurons of the NTS and enhanced sympathetic output from the PVN. These are in line with increased levels of kynurenic acid and 3-hydroxy kynurenine, and BP, respectively, suggesting that BP regulation by the gut-brain axis may be mediated by kynurenic pathway.

Monobutyrin and Monovalerin Affect Brain Short-Chain Fatty Acid Profiles and Tight-Junction Protein Expression in ApoE-Knockout Rats Fed High-Fat Diets.

Monobutyrin (MB) and monovalerin (MV), esters of short-chain fatty acids (SCFAs), have previously been shown to reduce liver cholesterol and inflammation in conventional rats fed high-fat diets. This study explored the potential effects of MB and MV in hypercholesterolemic apolipoprotein E-knockout (ApoE-/-) rats. ApoE-/- rats were fed three high-fat (HF) diets, pure or supplemented with MB or MV (1%), for 5 weeks. One group of conventional rats (C) was also fed the pure high-fat diet and another group of ApoE-/- rats a low-fat (LF) diet. Blood and liver lipids, urinary lactulose/mannitol, SCFAs (blood and brain), tight junction proteins (small intestine and brain), and inflammation-related markers (blood, brain, and liver) were analyzed. MV supplementation elevated serum high-density lipoprotein (HDL) cholesterol and valeric acid concentration (p < 0.05), while the amounts of isovaleric acid in the brain were reduced (p < 0.05). MB increased butyric acid amounts in the brain, while the plasma concentration of interleukin 10 (IL-10) was lowered (p < 0.05). Both MV and MB upregulated the expression of occludin and zonula occludens-1 (ZO-1) in the brain (p < 0.05). Supplementation of MB or MV affected HDL cholesterol, the expression of tight junction proteins, and SCFA profiles. MB and MV may therefore be promising supplements to attenuate lipid metabolic disorders caused by high-fat intake and genetic deficiency.

Inducible Kiss1 knockdown in the hypothalamic arcuate nucleus suppressed pulsatile secretion of luteinizing hormone in male mice.

Accumulating evidence suggests that kisspeptin-GPR54 signaling is indispensable for gonadotropin-releasing hormone (GnRH)/gonadotropin secretion and consequent reproductive functions in mammals. Conventional Kiss1 knockout (KO) mice and rats are reported to be infertile. To date, however, no study has investigated the effect of inducible central Kiss1 KO/knockdown on pulsatile gonadotropin release in male mammals. Here we report an in vivo analysis of inducible conditional Kiss1 knockdown male mice. The mice were generated by a bilateral injections of either adeno-associated virus (AAV) vectors driving Cre recombinase (AAV-Cre) or AAV vectors driving GFP (AAV-GFP, control) into the hypothalamic arcuate nucleus (ARC) of Kiss1-floxed male mice, in which exon 3 of the Kiss1 gene were floxed with loxP sites. Four weeks after the AAV-Cre injection, the mice showed a profound decrease in the both number of ARC Kiss1-expressing cells and the luteinizing hormone (LH) pulse frequency. Interestingly, pulsatile LH secretion was apparent 8 weeks after the AAV-Cre injection despite the suppression of ARC Kiss1 expression. The control Kiss1-floxed mice infected with AAV-GFP showed apparent LH pulses and Kiss1 expression in the ARC at both 4 and 8 weeks after the AAV-GFP injection. These results with an inducible conditional Kiss1 knockdown in the ARC of male mice suggest that ARC kisspeptin neurons are responsible for pulsatile LH secretion in male mice, and indicate the possibility of a compensatory mechanism that restores GnRH/LH pulse generation.

БИОХИМИЧЕСКИЕ ПОКАЗАТЕЛИ КРОВИ БЕСПОРОДНЫХ КРЫС

The aim of the work was to determine some biochemical parameters, taking into account the sex of the outbred (conventional) rats in the norm, used at the experiment to determine the reference val-ues. The experiments were carried out on 41 rats of 5-6 months age old., weighing 200-250 g, divided into two groups - males (n = 16) and fe-males (n = 25). Blood serum was obtained accord-ing to the generally accepted method. Blood serum was obtained according to standard methods. Biochemical parameters were analyzed on an IDEXX CatalystOne automated analyzer. Protein and carbohy-drate metabolism were analyzed by the se-rum levels of total protein (TP), albumin (Alb), urea (Urea), creatinine (Creat), glu-cose (Glu), the enzyme spectrum - by alka-line phosphatase (ALP), alanine and aspar-tate aminotransferase (ALT and AST), min-eral metabolism - by calcium (Ca), phospho-rus (P), sodium (Na), potassium (K), chlo-rine (Cl), as well as bile pigment - by total bilirubin (T.bil). De Ritis coefficient (AST / ALT), globulin (Glob), albumin/globulin ratio (A / G) was revealed by the calculation method. The results were taken into account in two versions: 1 - according to all animals (16 males and 25 females); 2 - according to samples from the general population in three replicates. It was found that out of 17 biochemical parameters -15 are constant, due to the sex of the experimental animals. So, females showed higher indicators of protein and min-eral metabolism, glucose, ALT, alkaline phosphatase, while in males this was record-ed only in four cases - in the content of urea and AST and in the ratios A / G, AST / ALT. Data on the content of creatinine and total bilirubin in the blood serum of rats were variable in nature and were close in value. Thus, the results of the studies carried out can be used in the future, for biochemical diagnostics of systematic metaboli

Изучение фармакокинетики нового радиофармацевтического препарата на основе меченной технецием-99m производной глюкозы

Purpose: To study the features of the distribution and removal of a new radiopharmaceutical (RPH) on the basis of a labeled 99mTc glucose derivative for radionuclide diagnostics of oncological diseases in the body of experimental animals.&#x0D; Material and methods: The main stage of the study was performed on 65 mature conventional outbred white rats and 9 rabbits of the Soviet Chinchilla breed. To study the dynamics of changes in the concentration of the studied RPH in the blood plasma and its distribution in the main organs and tissues, as well as to study the metabolic features of the drug and its excretion, the RPH studied was administered intravenously, once in activity of 20 MBq. Multiple introduction of the RPH was performed in order to study the cumulative properties of the study drug, and to elucidate the possibilities of predicting the cumulation processes from the data obtained with a single administration of RPH. For this purpose, intravenous RPH was administered at the same time 1 time / day for 5 days, at a dose of 20 MBq. To confirm the theory of linearity of the pharmacokinetics of the RFP studied, three groups of laboratory animals received the drug in three activity levels – 10, 20 and 40 MBq were used. After euthanasia, the animals were autopsied and removed the necessary organs and tissues. The prepared and washed organs were placed in tubes for further radiometry in order to study the concentrations of the RPH in the bioassay.&#x0D; Results: It has been established that the RPH being studied practically does not accumulate in the main organs and tissues, accumulating mainly in the kidneys and bladder. The main organs of elimination of the test drug are the kidneys, and the main excreta are urine. The half-life of the drug from the blood was 10 minutes. Pharmacokinetics of the drug is linear and does not depend on the administered activity, and the drug itself does not possess cumulative properties.&#x0D; Conclusion: A study of the pharmacokinetics of the RPH 99mTc-1-Thio-D-glucose showed that the preparation possesses optimal properties for the diagnostic agent. The drug stably does not accumulate in the main organs and tissues, which allows it to be reused, for example at the stages of dynamic observation of cancer patients.

Conventional and Specific-Pathogen Free Rats Respond Differently to Anesthesia and Surgical Trauma

Specific-pathogen free (SPF) animals were introduced in the 1960s to minimize disease and infection as variables in biomedical research. Our aim was to examine differences in physiological response in rat colonies bred and housed in a conventional versus SPF facility, and implications for research. Sprague-Dawley rats were anesthetized and catheterized for blood and pressure monitoring, and electrocardiogram (ECG) leads implanted. Hematology was assessed, and coagulation profile using rotational thromboelastometry. Health screening was outsourced to Cerberus Sciences. SPF rats had significantly lower pulse pressure (38% decrease), arrhythmias and prolonged QTc (27% increase) compared to conventional rats. No arrhythmias were found in conventional rats. SPF rats had significantly higher white cell, monocyte, neutrophil and lymphocyte counts, and were hyperfibrinolytic, indicated by EXTEM maximum lysis >15%. Independent assessment revealed similar pathogen exclusion between colonies, with the exception of Proteus in SPF animals. Returning to a conventional facility restored normal host physiology. We conclude that SPF animals displayed an abnormal hemodynamic, hematological and hemostatic phenotype in response to anesthesia and surgery, and provide a number of recommendations to help standardize research outcomes and translation.