Comparative Impact of Various Fasting Periods on the Welfare of Sprague-Dawley Rats With or Without Supplementation.

In nonclinical toxicology studies, lab animals are fasted typically overnight, to reduce variability in some clinical pathology parameters. However, fasting adds undue stress, and this is particularly concerning in rodents given their fast metabolic rates. Furthermore, as rodents are nocturnal animals, an overnight fasting may cause a protracted negative metabolic state even when the fasting has technically ended, given their minimal activity and food consumption during the day. Therefore, to evaluate the impacts of different fasting durations (±DietGel supplementation) on rats' welfare, we assessed the traditional and ancillary clinical pathology parameters in Sprague-Dawley rats, along with body weight, organ weight, and histopathology. Although most endpoints were comparable between the different fasting durations (±DietGel supplementation), the long fasting times (≥8 hr) without DietGel supplementation caused significant decreases in body weight, liver weight, liver glycogen content, serum glucose, triglyceride, and creatinine concentrations-all findings suggestive of a negative energy balance that could impact animal welfare and consequently, data quality; while the short fasting time (4 hr) and DietGel supplementation were associated with higher triglycerides variability. Hence, we propose that short fasting time should be adequate for most toxicology studies in rats, and long fasting times should only be accommodated with scientific justification.

Fish scale-derived hydroxyapatite for alveolar ridge preservation.

Alveolar ridge resorption following tooth extraction poses significant challenges for future dental restorations. This study investigated the efficacy of fish scale-derived hydroxyapatite (FSHA) as a socket preservation graft material to maintain alveolar bone volume and architecture. FSHA was extracted from *Labeo rohita* fish scales and characterized using Fourier transform infrared (FTIR) analysis. In vitro, biocompatibility and osteogenic potential were assessed using Saos-2 human osteosarcoma cells. Cell viability, migration, and proliferation were evaluated using MTT and scratch assays. In vivo performance was assessed in a rat model, and FSHA was compared to a commercial xenograft (Osseograft) and ungrafted controls. Histological analysis was performed at 8-week post-implantation to quantify new bone formation. FTIR confirmed the purity and homogeneity of FSHA. In vitro, FSHA enhanced Saos-2 viability, migration, and proliferation compared to controls. In vivo, FSHA demonstrated superior bone regeneration compared to Osseograft and ungrafted sites, with balanced graft resorption and new bone formation. Histological analysis revealed an active incorporation of FSHA into new bone, with minimal gaps and ongoing remodeling. Approximately 50%-60% of FSHA was resorbed by 8 weeks, closely matching the rate of new bone deposition. FSHA stimulated more bone formation in the apical socket region than in coronal areas. In conclusion, FSHA is a promising biomaterial for alveolar ridge preservation, exhibiting excellent biocompatibility, osteogenic potential, and balanced resorption. Its ability to promote robust bone regeneration highlights its potential as an effective alternative to currently used graft materials in socket preservation procedures.

Twenty-eight days of repeated dose sub-acute toxicological evaluation of polyherbal Ayurvedic medicine BPGrit in Sprague-Dawley rats.

A pre-clinical toxicological evaluation of herbal medicines is necessary to identify any underlying health-associated side effects, if any. BPGrit is an Ayurveda-based medicine prescribed for treating hypertensive conditions. High-performance liquid chromatography-based analysis revealed the presence of gallic acid, ellagic acid, coumarin, cinnamic acid, guggulsterone E, and guggulsterone Z in BPGrit. For sub-acute toxicity analysis of BPGrit, male and female Sprague-Dawley rats were given repeated oral gavage at 100, 300, and 1000 mg/kg body weight/day dosages for 28 days, followed by a 14-day recovery phase. No incidences of mortality, morbidity, or abnormal clinical signs were observed in BPGrit-treated rats throughout the study period. Also, the body weight and food consumption habits of the experimental animals did not change during the study duration. Hematological, biochemical, and histopathological analysis did not indicate any abnormal changes occurring in the BPGrit-treated rats up to the highest tested dose of 1000 mg/kg body weight/day. Finally, the study established the "no-observed-adverse-effect level" for BPGrit at >1000 mg/kg body weight/day in Sprague-Dawley rats.

Low-dose peripheral leptin infusion produces selective activation of ventromedial hypothalamic and hindbrain STAT3.

Previous studies have shown that very low dose, acute, single peripheral leptin injections fully activate arcuate nucleus signal transducer and activator of transcription 3 (STAT3), but ventromedial hypothalamus (VMH) pSTAT3 continues to increase with higher doses of leptin that inhibit food intake. The lowest dose that inhibited intake increased circulating leptin 300-fold whereas food intake is inhibited by chronic peripheral leptin infusions that only double circulating leptin. This study examined whether the pattern of hypothalamic pSTAT3 was the same in leptin-infused rats as in leptin-injected rats. Male Sprague-Dawley rats received intraperitoneal infusions of 0, 5, 10, 20, or 40 µg leptin/day for 9 days. The highest dose of leptin increased serum leptin by 50-100%, inhibited food intake for 5 days, but inhibited weight gain and retroperitoneal fat mass for 9 days. Energy expenditure, respiratory exchange ratio, and brown fat temperature did not change. pSTAT3 was quantified in hypothalamic nuclei and the nucleus of the solitary tract (NTS) when food intake was inhibited and when it had returned to control levels. There was no effect of leptin on pSTAT3 in the medial or lateral arcuate nucleus or in the dorsomedial nucleus of the hypothalamus. VMH pSTAT3 was increased only at day 4 when food intake was inhibited, but NTS pSTAT3 was increased at both 4 and 9 days of infusion. These results suggest that activation of leptin VMH receptors contributes to the suppression of food intake, but that hindbrain receptors contribute to a sustained change in metabolism that maintains a reduced weight and fat mass.NEW & NOTEWORTHY Low-dose, chronic peripheral infusions of leptin produced an initial, transient inhibition of food intake that correlated with signal transducer and activator of transcription 3 (STAT3) activation in the ventromedial hypothalamus (VMH) and nucleus of the solitary tract (NTS). When intake normalized, but weight remained suppressed, the NTS was the only area that remained activated. These data suggest that leptin's primary function is to reduce body fat, that hypophagia is a means of achieving this and that different areas of the brain are responsible for the progressive response.

Assessing the Carcinogenicity of Vadadustat, an Oral Hypoxia-Inducible Factor Prolyl-4-Hydroxylase Inhibitor, in Rodents.

Vadadustat is an investigational oral hypoxia-inducible factor (HIF) prolyl-4-hydroxylase inhibitor to treat anemia due to chronic kidney disease (CKD). Some studies suggest that HIF activation promotes tumorigenesis by activating angiogenesis downstream of vascular endothelial growth factor, while other studies suggest that elevated HIF activity may produce an antitumor phenotype. To evaluate the potential carcinogenicity of vadadustat in mice and rats, we dosed CByB6F1/Tg.rasH2 hemizygous (transgenic) mice orally by gavage with 5 to 50 mg/kg/d of vadadustat for 6 months and dosed Sprague-Dawley rats orally by gavage with 2 to 20 mg/kg/d for approximately 85 weeks. Doses were selected based on the maximally tolerated dose established for each species in previous studies. The tumors that were identified in the studies were not considered to be treatment-related for statistical reasons or within the historical control range. There was no carcinogenic effect attributed to vadadustat in mice or rats.

Efficacy of KPR-5714, a selective transient receptor potential melastatin 8 antagonist, on chronic psychological stress-induced bladder overactivity in male rats.

AIMS: Chronic psychological stress aggravates lower urinary tract symptoms. Among others, water avoidance stress is a chronic psychological stressor that plays a causal role in the exacerbation and development of bladder dysfunction in rats. In this report, the effects of KPR-5714, which is a selective transient receptor potential melastatin 8 (TRPM8) antagonist, on bladder overactivity induced by water avoidance stress were examined. METHODS: Male rats were subjected to water avoidance stress for 2 h per day for 10 consecutive days. The effects of water avoidance stress on voiding behavior using metabolic cages and histological bladder changes were investigated in rats. The involvement of bladder C-fiber afferent on voiding frequency in rats exposed to water avoidance stress was assessed using capsaicin. The effects of KPR-5714 on storage dysfunction in rats subjected to water avoidance stress were examined. RESULTS: In voiding behavior measurements, water avoidance stress-induced storage dysfunction, causing a decrease in the mean voided volume and increasing voiding frequency. A comparison of bladders from normal rats and rats exposed to water avoidance stress showed no histological differences. Water avoidance stress-induced bladder overactivity was completely inhibited by pretreatment with capsaicin. KPR-5714 showed a tendency to increase the mean voided volume and significantly decreased the voiding frequency without affecting the total voided volume in these rats. CONCLUSION: The results suggest that KPR-5714 is a promising option for treating chronic psychological stress-induced bladder overactivity.

Heterogeneous deposition of regular and mentholated little cigar smoke in the lungs of Sprague-Dawley rats.

BACKGROUND: Quantifying the dose and distribution of tobacco smoke in the respiratory system is critical for understanding its toxicity, addiction potential, and health impacts. Epidemiologic studies indicate that the incidence of lung tumors varies across different lung regions, suggesting there may be a heterogeneous deposition of smoke particles leading to greater health risks in specific regions. Despite this, few studies have examined the lobar spatial distribution of inhaled particles from tobacco smoke. This gap in knowledge, coupled with the growing popularity of little cigars among youth, underscores the need for additional research with little cigars. RESULTS: In our study, we analyzed the lobar deposition in rat lungs of smoke particles from combusted regular and mentholated Swisher Sweets little cigars. Twelve-week-old male and female Sprague-Dawley rats were exposed to smoke particles at a concentration of 84 ± 5 mg/m3 for 2 h, after which individual lung lobes were examined. We utilized Inductively Coupled Plasma Mass Spectrometry to quantify lobar chromium concentrations, serving as a smoke particle tracer. Our findings demonstrated an overall higher particle deposition from regular little cigars than from the mentholated ones. Higher particle deposition fraction was observed in the left and caudal lobes than other lobes. We also observed sex-based differences in the normalized deposition fractions among lobes. Animal study results were compared with the multi-path particle dosimetry (MPPD) model predictions, which showed that the model overestimated particle deposition in certain lung regions. CONCLUSIONS: Our findings revealed that the particle deposition varied between different little cigar products. The results demonstrated a heterogenous deposition pattern, with higher particle deposition observed in the left and caudal lobes, especially with the mentholated little cigars. Additionally, we identified disparities between our measurements and the MPPD model. This discrepancy highlights the need to enhance the accuracy of models before extrapolating animal study results to human lung deposition. Overall, our study provides valuable insights for estimating the dose of little cigars during smoking for toxicity research.

Subchronic toxicity study of ferric oxide nanoparticles through intragastric administration: A 94-d, repeated dose study in Sprague Dawley rats.

In this study, the toxicity of ferric oxide nanoparticles (Fe2O3 NPs) administered through gavage to Sprague Dawley (SD) rats for 94 d, consecutively and the recovery after Fe2O3 NPs withdrawal for 30 d were evaluated. The vehicle control group, low-, medium-, and high-dose groups were administered with the vehicle (0.5% sodium carboxymethyl cellulose [CMC-Na]), 125, 250, and 500 mg/kg of Fe2O3 NPs, respectively, administered every morning for 94 d. There was no significant difference in the body weight, food intake, hematological, blood biochemical, and urine indices of SD rats in each administration group and the control group (P > 0.05). There was no significant difference in organ weight, organ indices, and the coefficient of the visceral brain between the SD rats in the different dosage groups and the SD rats in the vehicle control group (P > 0.05). Histopathological observations showed that there was no correlation between the pathological lesions of the organs observed in this study and the dose of Fe2O3 NPs (P > 0.05). The no-observed-adverse-effect level (NOAEL) dose of Fe2O3 NPs was initially determined to be 500 mg/kg administered to SD rats through oral gavage for 94 d, consecutively, followed by recovery after Fe2O3 NPs withdrawal for 30 d.

Metabolomics of Type 2 Diabetes Mellitus in Sprague Dawley Rats-In Search of Potential Metabolic Biomarkers.

Type 2 diabetes mellitus (T2DM) is an expanding global health concern, closely associated with the epidemic of obesity. Individuals with diabetes are at high risk for microvascular and macrovascular complications, which include retinopathy, neuropathy, and cardiovascular comorbidities. Despite the availability of diagnostic tools for T2DM, approximately 30-60% of people with T2DM in developed countries are never diagnosed or detected. Therefore, there is a strong need for a simpler and more reliable technique for the early detection of T2DM. This study aimed to use a non-targeted metabolomic approach to systematically identify novel biomarkers from the serum samples of T2DM-induced Sprague Dawley (SD) rats using a comprehensive two-dimensional gas chromatography coupled with a time-of-flight mass spectrometry (GCxGC-TOF/MS). Fifty-four male Sprague Dawley rats weighing between 160-180 g were randomly assigned into two experimental groups, namely the type 2 diabetes mellitus group (T2DM) (n = 36) and the non-diabetic control group (n = 18). Results from this study showed that the metabolite signature of the diabetic rats was different from that of the non-diabetic control group. The most significantly upregulated metabolic pathway was aminoacyl-t-RNA biosynthesis. Metabolite changes observed between the diabetic and non-diabetic control group was attributed to the increase in amino acids, such as glycine, L-asparagine, and L-serine. Aromatic amino acids, including L-tyrosine, were associated with the risk of future hyperglycemia and overt diabetes. The identified potential biomarkers depicted a good predictive value of more than 0.8. It was concluded from the results that amino acids that were associated with impaired insulin secretion were prospectively related to an increase in glucose levels. Moreover, amino acids that were associated with impaired insulin secretion were prospectively related to an increase in glucose levels.

Metabolomics (Non-Targeted) of Induced Type 2 Diabetic Sprague Dawley Rats Comorbid with a Tissue-Dwelling Nematode Parasite.

Type 2 diabetes is a non-communicable metabolic syndrome that is characterized by the dysfunction of pancreatic ß-cells and insulin resistance. Both animal and human studies have been conducted, demonstrating that helminth infections are associated with a decreased prevalence of type 2 diabetes mellitus (T2DM). However, there is a paucity of information on the impact that helminths have on the metabolome of the host and how the infection ameliorates T2DM or its progression. Therefore, this study aimed at using a non-targeted metabolomics approach to systematically identify differentiating metabolites from serum samples of T2DM-induced Sprague Dawley (SD) rats infected with a tissue-dwelling nematode, Trichinella zimbabwensis, and determine the metabolic pathways impacted during comorbidity. Forty-five male SD rats with a body weight between 160 g and 180 g were used, and these were randomly selected into control (non-diabetic and not infected with T. zimbabwensis) (n = 15) and T2DM rats infected with T. zimbabwensis (TzDM) (n = 30). The results showed metabolic separation between the two groups, where d-mannitol, d-fructose, and glucose were upregulated in the TzDM group, when compared to the control group. L-tyrosine, glycine, diglycerol, L-lysine, and L-hydroxyproline were downregulated in the TzDM group when compared to the control group. Metabolic pathways which were highly impacted in the TzDM group include biotin metabolism, carnitine synthesis, and lactose degradation. We conclude from our study that infecting T2DM rats with a tissue-dwelling nematode, T. zimbabwensis, causes a shift in the metabolome, causing changes in different metabolic pathways. Additionally, the infection showed the potential to regulate or improve diabetes complications by causing a decrease in the amino acid concentration that results in metabolic syndrome.

The Role of Myeloperoxidase in Clozapine-Induced Inflammation: A Mechanistic Update for Idiosyncratic Drug-Induced Agranulocytosis.

The risk of idiosyncratic drug-induced agranulocytosis (IDIAG) markedly constrains the use of clozapine, a neuroleptic with unparalleled efficacy. Most clozapine patients experience an early inflammatory response, likely a necessary step in IDIAG onset. However, most patients do not progress to IDIAG, presumably because of the requirement of specific human leukocyte antigen (HLA) haplotypes, T cell receptors, and other unknown factors. We established that clozapine activates inflammasomes and that myeloperoxidase bioactivation of clozapine generates neoantigens, but the connection between these early mechanistic events remained unknown and, thus, was the aim of this work. We found that the myeloperoxidase inhibitor PF-1355 attenuated myeloperoxidase activity in phorbol myristate acetate (PMA)-differentiated THP-1 macrophages, and it also attenuated clozapine-induced release of inflammatory mediators (e.g., IL-1ß, CXCL1, and C-reactive protein). In vivo, pretreatment of Sprague Dawley rats with PF-1355 significantly attenuated clozapine-induced increases in neutrophil mobilization from the bone marrow to the blood and spleen, as determined using differential blood counts and flow cytometry. Moreover, the clozapine-triggered release of inflammatory mediators (e.g., IL-1ß, calprotectin, CXCL1, and α-1-acid glycoprotein) from the liver, spleen, and bone marrow was dampened by myeloperoxidase inhibition. These data support the working hypothesis that oxidation of clozapine to a reactive metabolite by myeloperoxidase is critical for induction of the inflammatory response to clozapine. Ultimately, a better mechanistic understanding of the early events involved in the immune response to clozapine may elucidate ways to prevent IDIAG, enabling safer, more frequent therapeutic use of this and potentially other highly efficacious drugs.

[Near-infrared targeted probe designed for intraoperative imaging of prostatic neurovascular bundles].

OBJECTIVE: To investigate the imaging effect of a near-infrared fluorescent targeted probe ICG-NP41 on the neurovascular bundles (NVB) around the prostate in rats. METHODS: A near-infrared fluorescent targeted probe ICG-NP41 was synthesized. An animal model for NVB imaging was established using Sprague-Dawley rats (250-400 g). Experiments were conducted using a custom-built near-infrared windowⅡ(NIR-Ⅱ) small animal in vivo imaging system, and images collected were processed using ImageJ and Origin. The fluorescence signal data were statistically analyzed using GraphPad Prism. The signal-to-background ratio (SBR) for NVB was quantitatively calculated to explore the effective dosage and imaging time points. Finally, paraffin pathology sections and HE staining were performed on the imaging structures. RESULTS: Except for rats in the control group (n=2), right-sided NVB of the rats injected with ICG-NP41 (n=2 per group) were all observed in NIR-Ⅱ fluorescence mode 2 h and 4 h after administration. At 2 h and 4 h, average SBR of cavernous nerve in 2 mg/kg group in fluorescence mode was 1.651±0.142 and 1.619±0.110, respectively, both higher than that in white light mode (1.111±0.036), with no significant difference (P>0.05); average SBR of 4 mg/kg group in fluorescence mode were 1.168±0.066 and 1.219±0.118, respectively, both higher than that in white light mode (1.081±0.040), with no significant difference (P>0.05). At 2 h and 4 h, the average SBR of 2 mg/kg and 4 mg/kg groups in fluorescence mode were higher than that of the control group (SBR=1), the average SBR of the 2 mg/kg group was higher than that of the 4 mg/kg group, and all the above with no significant difference (P>0.05). The average diameter of the nerve measured by full width at half maxima method was about (178±15) µm. HE staining of paraffin sections showed the right major pelvic ganglion. CONCLUSION: The near-infrared fluorescent targeted probe ICG-NP41 can be used for real-time imaging of the NVB around the prostate in rats, providing a potential feasible solution for localizing NVB in real time during nerve-sparing radical prostatectomy.

Jaboticaba (Myrciaria cauliflora) Fruit Extract Suppressed Aberrant Crypt Formation in 1,2-Dimetylhydrazine-Induced Rats.

Early intervention can significantly improve the colorectal cancer survival rate. Foods rich in phenolic compounds, such as jaboticaba (Myrciaria cauliflora), may prevent tumorigenesis. We investigated the effectivity of jaboticaba whole fruit ethanolic extract (FEX) in suppressing aberrant crypt foci (ACF), the earliest lesion of colorectal cancer (CRC), in 1,2-dimethylhydrazine (DMH)-induced rats and the underlying mechanisms related to the gut microbiota composition and short chain fatty acid (SCFA). This study was approved by the Institutional Animal Care and Use Committee (IACUC) of Providence University (Trial Registration Number 20180419A01, registration date: 22 December 2018). The FEX contains gallic acid and an especially high ellagic acid concentration of 54.41 ± 1.80 and 209.79 ± 2.49 mg/100 g FEX. The highest total ACF number (150.00 ± 43.86) was recorded in the DMH control (D) group. After 56 days of oral FEX treatment, the total ACF number in the low FEX dosage (DL) group was significantly lower compared to the D group (p < 0.05). The large-sized ACF (> 5 foci), which has a higher probability of progressing to later stage, was significantly decreased in the high FEX dosage (DH) group. The 16s rDNA metagenomic sequencing of the cecal material revealed that the CRC biomarker Lachnoclostridium was significantly suppressed in the DH group (p < 0.05), whereas some SCFA-producing taxa and the cecal butyrate concentration were significantly elevated in the DL and DH groups (p < 0.05). This study demonstrated the potential of jaboticaba whole fruit in CRC prevention, especially in the initial stage, by shifting gut microbiota composition and improving cecal butyrate level.

Leptin receptor-expressing cells in the ventromedial nucleus of the hypothalamus contribute to enhanced CCK-induced satiety following central leptin injection.

Others have shown that leptin and cholecystokinin (CCK) act synergistically to suppress food intake. Experiments described here tested whether leptin in the ventromedial hypothalamus (VMH) contributes to the synergy with peripheral CCK in male Sprague Dawley rats. A subthreshold injection of 50-ng leptin into the VMH 1 h before a peripheral injection of 1 µg/kg CCK did not change the response to CCK in rats offered chow or low-fat purified diet, but did exaggerate the reduction in intake of high-fat diet 30 min and 1 h after injection in rats that had been food deprived for 8 h. By contrast, deletion of leptin receptor-expressing cells in the VMH using leptin-conjugated saporin (Lep-Sap) abolished the response to peripheral CCK in chow-fed rats. Lateral ventricle injection of 2-µg leptin combined with peripheral CCK exaggerated the inhibition of chow intake for up to 6 h in control rats treated with Blank-saporin, but not in Lep-Sap rats. Blank-Saporin rats offered low- or high-fat purified diet also demonstrated a dose-response inhibition of intake that reached significance with 1 µg/kg of CCK for both diets. CCK did not inhibit intake of Lep-Sap rats in either low- or high-fat-fed rats. Thus, although basal activation of VMH leptin receptors makes a significant contribution to the synergy with CCK, increased leptin activity in the VMH does not exaggerate the response to CCK in intact rats offered low-fat diets, but does enhance the response in those offered high-fat diet.NEW & NOTEWORTHY Leptin is a feedback signal in the control of energy balance, whereas cholecystokinin (CCK) is a short-term satiety signal that inhibits meal size. The two hormones synergize to promote satiety. We tested whether leptin receptors in the ventromedial nucleus of the hypothalamus (VMH) contribute to the synergy. The results suggest that there is a requirement for a baseline level of activation of leptin receptors in the VMH in order for CCK to promote satiety.

Optimizing intraluminal monofilament model of ischemic stroke in middle-aged Sprague-Dawley rats.

Intraluminal monofilament model of middle cerebral artery occlusion (MCAO) is widely adopted for ischemic stroke; and Sprague-Dawley (SD) rats are commonly used rodents for preclinical research. Due to the paucity of information on the appropriate monofilament size for inducing MCAO in SD rats and the importance of including middle-aged models in ischemic stroke studies, we aimed to: (i). determine an appropriate Doccol® monofilament size for middle-aged male SD rats which weighed > 500 g following 24-h transient MCAO survival as well as (ii). demonstrate the optimal Doccol® filament size for middle-aged males (≤ 500 g) and females (273-300 g) while using young adult male SD rats (372-472 g) as control for severity of infarct volume following 7-days post-MCAO. All rats were subjected to 90-min transient MCAO. We show that 0.43 mm Doccol® monofilament size is more appropriate to induce large infarct lesion and optimal functional deficit when compared to 0.45 mm and 0.47 mm at 24 h post-MCAO. Our data on infarct volumes at 7 days post-MCAO as well as the observed weight loss and functional deficits at post-MCAO days 1, 3 and 7 demonstrate that 0.41 mm, 0.37 mm and 0.39 mm are optimal Doccol® filament sizes for middle-aged male (477.3 ± 39.61 g) and female (302.6 ± 26.28 g) as well as young-adult male (362.2 ± 28.38 g) SD rats, respectively.

KPR-5714, a selective transient receptor potential melastatin 8 antagonist, improves voiding dysfunction in rats with bladder overactivity but does not affect voiding behavior in normal rats.

AIMS: Transient receptor potential melastatin 8 (TRPM8) has a role in the abnormal sensory transduction of the bladder and is involved in the pathophysiology of hyperactivity bladder disorders. The aim of this study is to examine the effects of KPR-5714, a novel and selective TRPM8 antagonist, on voiding dysfunction induced by bladder afferent hyperactivity via mechanosensitive C-fibers in rats. METHODS: The effects of intragastric administration of KPR-5714 on bladder overactivity induced by intravesical instillation of 10 mM ATP were investigated using cystometry in conscious female rats. We examined the effects of oral administration of KPR-5714 on voiding behavior using a metabolic cage in normal male rats and rats with an intratesticular injection of 3% acetic acid. RESULTS: In cystometry measurements, the intercontraction interval was decreased by intravesical ATP instillation. KPR-5714 (0.1, 0.3, and 1 mg/kg) dose-dependently prolonged the shortened intercontraction interval provoked by ATP. In voiding behavior measurements, intratesticular injection of acetic acid decreased the mean voided volume and increased voiding frequency. KPR-5714 (0.1 and 0.3 mg/kg) dose-dependently increased the mean voided volume and decreased voiding frequency without affecting the total voided volume in these rats. However, KPR-5714 (1 and 10 mg/kg) did not influence the voiding behavior in normal rats. CONCLUSION: The present results suggest that KPR-5714 improves voiding dysfunction by inhibiting the enhanced activity of mechanosensitive bladder C-fibers in rats with bladder overactivity and shows no significant change in voiding behavior in normal rats.

The effects of long-term moderate exercise and Western-type diet on oxidative/nitrosative stress, serum lipids and cytokines in female Sprague Dawley rats.

PURPOSE: Regular exercise reduces obesity and the risk of cardiovascular disease. However, health-promoting benefits of physical activity are commonly associated with increased inflammation and oxidative stress. Here, we tested whether constant moderate exercise is able to prevent or attenuate the oxidative/nitrosative stress, inflammation, and serum lipids in lean and obese rats. METHODS: Four-month-old female Sprague Dawley rats received standard or a high-fat diet. Animals were subjected to a physical activity protocol, consisting of 30 min forced treadmill exercise for 5 consecutive days per week during 10 months. Baseline and sedentary (non-exercised) rats were used as controls. Lipids, oxidized low-density lipoprotein cholesterol, nitric oxide metabolites, and pro- and anti-inflammatory markers were measured in blood collected upon euthanasia. RESULTS: At variance to young baseline control rats, 14-month-old animals fed normal diet had increased plasma lipid levels, including total cholesterol and triglycerides, which were further elevated in rats that consumed a high-fat diet. While treadmill exercise did not lower the amount of serum lipids in standard diet group, forced physical activity reduced non-high-density lipoprotein cholesterol in response to high-fat diet feeding. Exercised rats fed standard diet or high-fat diet had lower abundancy of nitric oxide metabolites, which coincided with increased levels of oxidized low-density lipoprotein cholesterol. Accordingly, the amount of nitric oxide metabolites correlated inversely with oxidized low-density lipoprotein cholesterol and homo-arginine. Exercise significantly reduced inflammatory cytokines in high-fat diet fed rats only. CONCLUSION: Our study suggests that regular exercise alters the equilibrium between oxidative and anti-oxidative compounds and reduces pro-inflammatory cytokines.

Hepatic metabolism of chlorinated derivatives of bisphenol A (ClxBPA) and interspecies differences between rats and humans.

During chlorination treatments of drinking water, aqueous bisphenol A (BPA) can react with chlorine to form chlorinated derivatives of BPA (mono, di, tri and tetra-chlorinated derivatives) or ClxBPA. These emerging substances are endocrine disruptors associated with obesity, type II diabetes (TD2M) and myocardial infarction. ClxBPA are present in different human biological matrices but their toxicokinetics remain unknown. The aim of this study was to measure and compare the metabolic kinetics in the liver of four ClxBPA (ClBPA, Cl2BPA, Cl3BPA and Cl4BPA) between compounds and between species (Sprague-Dawley rats vs humans). To estimate their metabolic constants (Vmax, Km, Intrinsic clearance), metabolic assays were performed in hepatocyte suspensions. Assays revealed that metabolic constants of ClxBPA can greatly vary depending on substances and species. While ClBPA and Cl2BPA show similar unbound intrinsic clearances (ClintU) in rat incubation media, values for Cl3BPA and Cl4BPA are very different (3.109 and 0.684 mL/min/106 hepatocytes, respectively). Unlike in rats, human results are quite different as Cl3BPA and Cl4BPA have similar unbound intrinsic clearances, while ClBPA and Cl2BPA diverge (0.350 and 1.363 mL/min/106 hepatocytes, respectively). In both species, Cl2BPA and Cl3BPA have relatively similar clearances, and ClBPA is very different from Cl4BPA. Although we quantified the proportion of sulfo- and glucurono-metabolites, other metabolites may have been formed (e.g., glutathione, disulfate, or oxidative metabolites). This study showed that chlorination had an impact on hepatic intrinsic clearance of ClxBPA in rats and humans and measured values will be valuable for the development of PBPK models for use in exposure assessment.

[Effects of 275 nm and 310 nm ultraviolet irradiation on bone metabolism in ovariectomized osteoporotic rats].

OBJECTIVE: To investigate the effect of 275 nm and 310 nm ultraviolet irradiation on ovariectomized rats' bone metabolism. METHODS: Twenty four 3-month-old female Sprague-Dawley (SD) rat were randomly divided into control group, sham operated group, 275 nm ultraviolet (UV) irradiation group and 310 nm UV irradiation group. Each group contained 6 rats. The rats in the two irradiation groups were treated with bilateral ovariectomy. The rats in sham operated group received sham operation (They were given the same back incision and a bit of par-ovarian fat were removed). Control group received no disposition. About 24 weeks after operation, all the rats received detailed bone mineral density (BMD) detection again. Detection regions include cervical vertebra, lumbar vertebra, proximal femur, mid femur and distal femur. Next, osteopenia rats in 275 nm irradiation group were UV irradiated 275 nm with fixed illumination intensity (15 µW/cm2) everyday for 16 weeks. The osteopenia rats in 310 nm irradiation group were UV irradiated 310 nm with fixed illumination intensity (15 µW/cm2) everyday for 16 weeks. The backs of the rats were shaved regularly as irradiation area (6 cm×8 cm). After 16-week irradiation, all the rats' BMD of cervical vertebra, lumbar vertebra, proximal femur, mid femur and distal femur were measured. At the end of the trial, all the rats' blood specimens were obtained and serum 25(OH)D, procollagen type Ⅰ N-peptide (PINP) and osteocalcin (OC) were measured. RESULTS: Compared with control group [(238.78±26.74) mg/cm3], the BMD of the whole body were significantly lower in 275 nm [(193.34±13.28) mg/cm3] and 310 nm [(191.19±18.48) mg/cm3] irradiation groups (P=0.002, P=0.001). There were no significant difference between sham operated group [(227.20±14.32) mg/cm3] and control group. After 16-week ultraviolet irradiation, the BMD of the whole body were significantly increased in 275 nm [(193.34±13.28) mg/cm3 vs. (221.68±25.52) mg/cm3, P=0.005] and 310 nm groups [(191.19±18.48) mg/cm3 vs. (267.48±20.54) mg/cm3, P < 0.001] after corresponding irradiation. The BMD of the four body regions (lumbar vertebra, proximal femur, mid femur and distal femur) had significantly increased after irradiation in 275 nm irradiation group. For 310 nm irradiation group, the BMD in cervical vertebra, lumbar vertebra, proximal femur, mid femur and distal femur also had increased significantly after 310 nm ultraviolet irradiation. The concentration of serum 25(OH)D and OC was higher in 275 nm irradiation group than in control group [(46.78±5.59) µg/L vs. (21.32±6.65) µg/L, P=0.002;(2.05±0.53) U/L vs. (1.32±0.07) U/L, P=0.022]. Compared with the control, the concentration of serum 25(OH)D [(58.05±12.74) µg/L], OC [(2.04±0.53) U/L] and PINP [(176.16±24.18) U/L] was significantly higher (P < 0.001, P=0.015, P=0.005) in 310 nm irradiation group. However, there were no significantly difference between sham operated group and the control. CONCLUSION: Both 275 nm and 310 nm ultraviolet could improve rats' vitamin D synthesis. Both 275 nm and 310 nm ultraviolet could improve osteopenia rats' bone condition. The irradiation of 310 nm might be more effective on bone condition improvement.

Modeling of Chronic Lung Inflammation in Rats by Repeated Intratracheal Administration of LPS.

A model of a chronic lung inflammation in SPF Sprague-Dawley rats was developed by repeated intratracheal administration of LPS in a dose of 0.4 mg/kg. On day 22 of the study, male rats treated with LPS have relative monocytopenia and reduced mean concentration of hemoglobin in the erythrocyte and the mean platelet volume in comparison with the control animals (saline). Intratracheal administration of LPS induced an inflammatory process in the lungs characterized by focal atelectasis, compensatory emphysematous expansion of subpleural pulmonary acini, focal mononuclear and neutrophilic perivascular and peribronchial infiltration, and minor focal mononuclear and neutrophilic infiltration of the alveolar walls. Against the background of LPS administration, germinal centers appeared in the lymphoid follicles of the white pulp of the spleen, and focal mononuclear infiltration of the tracheal mucosa and/or submucosa was observed in some animals.