Increase in Bone Mass Before Onset of Type 1 Diabetes Mellitus in Rats.

BACKGROUND/AIM: The typical insulin deficiency in type 1 diabetes mellitus has general effects on metabolism and also affects bone quality. MATERIALS AND METHODS: Two diabetic rat lines (BB/OK; BB.6KWR) and two non-diabetic rat strains (KWR and BB.14+18KWR), as control group, were included in the study. Bone mineral density, bone mineral content and body structure measurements were performed. The measurements took place before the onset of diabetes mellitus Results: A comparison of the groups showed increased bone density values of the diabetic rats in relation to the control groups. A new finding of increased bone density in the diabetic rats occurs. CONCLUSION: Diabetic rats showed no osteoporotic bone metabolism before the onset of clinically relevant type 1 diabetes mellitus, but rather increased bone metabolic activity.

Potential involvement of nicotinamide N-methyltransferase in the pathogenesis of metabolic syndrome.

BACKGROUND: Metabolic syndrome is a complex disorder characterized by the presence of insulin resistance (IR), type 2 diabetes mellitus (T2DM), impaired glucose tolerance (IGT), or impaired fasting glucose (IFG), plus at least two of the following conditions--hypertension, hyperlipidemia, obesity, and microalbuminuria. Metabolic syndrome exposes patients to a greater risk of developing cardiovascular disease (CVD) and is often associated with elevated levels of homocysteine (Hcy). In the current work, we analyzed the expression of nicotinamide N-methyltransferase (NNMT). Because NNMT is involved in Hcy metabolism and participates in the regulation of the cellular and plasma levels of this compound, we explored the role played by the enzyme in metabolic syndrome. METHODS: Real-time PCR, immunohistochemistry, western blot analysis, and catalytic activity assay were performed to evaluate NNMT expression levels in adipose tissue from 10 Wistar Ottawa Karlsburg W (WOKW) rats, which are an animal model for metabolic syndrome, and from 10 Dark Agouti (DA) rats as the disease-resistant control strain. RESULTS: NNMT mRNA, protein, and activity levels were significantly higher in adipose tissue obtained from WOKW rats compared with those observed in adipose tissue of DA rats. CONCLUSION: Data reported in this study represent the first evidence supporting the hypothesis that NNMT could play an important role in the pathogenesis of metabolic syndrome and could have a potential for the development of a targeted therapy.

High-fat diet-induced met-hemoglobin formation in rats prone (WOKW) or resistant (DA) to the metabolic syndrome: effect of CoQ10 supplementation.

The aim of this study was to evaluate the effects of a high-fat diet (HFD) on oxidative indexes in WistarOttawaKarlsburg W (WOKW) rats used as a model of metabolic syndrome in comparison with Dark Agouti (DA) rats used as a control strain. This syndrome is defined by the occurrence of two or more risk factors including obesity, hypertension, dyslipidemia, and insulin resistance. Forty rats were used in the study and the effect of HFD was evaluated in terms of body weight and both hemoglobin and CoQ oxidative status. Moreover, 16 rats (8 of each strain) were supplemented with 3 mg/100 g b.w. of CoQ10 for 1 month in view of its beneficial properties in cardiovascular disease due to its antioxidant activity in the lipid environment. HFD promoted an increase in body weight, in particular in WOKW males, and in the methemoglobin (met-Hb) index in both strains. Moreover, HFD promoted endogenous CoQ10 oxidation. CoQ10 supplementation was able to efficiently counteract the HFD pro-oxidant effects, preventing met-Hb formation and CoQ oxidation.

Liver-restricted Repin1 deficiency improves whole-body insulin sensitivity, alters lipid metabolism, and causes secondary changes in adipose tissue in mice.

Replication initiator 1 (Repin1) is a zinc finger protein highly expressed in liver and adipose tissue and maps within a quantitative trait locus (QTL) for body weight and triglyceride (TG) levels in the rat. The QTL has further been supported as a susceptibility locus for dyslipidemia and related metabolic disorders in congenic and subcongenic rat strains. Here, we elucidated the role of Repin1 in lipid metabolism in vivo. We generated a liver-specific Repin1 knockout mouse (LRep1(-/-)) and systematically characterized the consequences of Repin1 deficiency in the liver on body weight, glucose and lipid metabolism, liver lipid patterns, and protein/mRNA expression. Hyperinsulinemic-euglycemic clamp studies revealed significantly improved whole-body insulin sensitivity in LRep1(-/-) mice, which may be due to significantly lower TG content in the liver. Repin1 deficiency causes significant changes in potential downstream target molecules including Cd36, Pparγ, Glut2 protein, Akt phosphorylation, and lipocalin2, Vamp4, and Snap23 mRNA expression. Mice with hepatic deletion of Repin1 display secondary changes in adipose tissue function, which may be mediated by altered hepatic expression of lipocalin2 or chemerin. Our findings indicate that Repin1 plays a role in insulin sensitivity and lipid metabolism by regulating key genes of glucose and lipid metabolism.

The polygenetically inherited metabolic syndrome of male WOKW rats is associated with enhanced autophagy in adipose tissue.

BACKGROUND: Recent studies revealed that autophagy is up-regulated in obese individuals, as evidenced by increased expression of autophagy related genes. As argued elsewhere, it is possible that initially insulin resistance functions as an adaptive mechanism to increase autophagy in order to protect cells against death. We have shown that Wistar Ottawa Karlsburg W (RT1(u)) rats (WOKW) develop a metabolic syndrome with insulin resistance in adipose tissue, closely resembling the human disease. Therefore, the aim of this study was to characterize the autophagy phenotype in WOKW rats to clarify the interrelation between insulin resistance and autophagy in adipose tissue. METHODS: Subcutaneous and epidydimal adipose tissue samples of 5-months-old WOKW and healthy LEW.1 W male rats were investigated and protein levels (Western blot and immunhistochemistry) of key autophagy genes, including Atg5, Atg7, LC3-II/LC3-I and apoptosis marker cleaved caspase-3 were analyzed. RESULTS: WOKW rats displayed a significant increase of autophagy related proteins (Atg5, Atg7) in adipose tissue compared with LEW.1 W. This increase was predominantly found in epididymal adipose tissue. Furthermore, the LC3-II/LC3-I ratio as a marker of autophagosomes was significantly up-regulated in subcutaneous adipose tissue of WOKW rats. Cleaved caspase-3 was just slightly detectable in visceral adipose tissue and not detected in subcutaneous fat. CONCLUSION: Insulin resistance in adipose tissue of obese WOKW rats is associated with up-regulation of differing autophagy markers in visceral and subcutaneous fat depots. This fact not only qualifies the WOKW rat for further detailed analysis of genetic determinants of metabolic syndrome but also highlights its suitability for autophagy research.

Light rhythm and diet differently influence facets of the metabolic syndrome in WOKW rats.

It has previously been shown that high-calorie diet alters the function of the mammalian circadian clock and that obesity has an influence on circadian organization of hormone secretion. That prompted us to test whether inbred Wistar Ottawa Karlsburg W (RT1(u)) (WOKW) rats developing facets of the metabolic syndrome show changes in their metabolic profiles under different feeding conditions (high-fat, high-sugar versus control diet) and under two different 12 h:12 h light-dark (LD) cycles. At the age of four weeks, these rats were divided into four groups. Groups 1 and 2 were kept under initial LD cycle (lights on at 05:00 h). Group 1 was fed with a normal rat diet while group 2 received a high-fat, high-sugar diet from 10 up to the age of 21 weeks. Groups 3 and 4 were kept under a shifted LD cycle (lights on at 11:00 h). Group 3 was given a normal diet while group 4 received a high-fat, high-sugar diet from an age like groups 1 and 2. Several metabolic traits were studied during the observation period of 21 weeks. The blood samples were obtained 2 h before lights off. Body weight gain (P < 0.001), leptin (P < 0.001), triglycerides (P < 0.001) and cholesterol (P < 0.05) were significantly reduced in group 4 versus group 2, but comparable between control groups (1 versus 3). The insulin concentrations were reduced in groups 3 and 4 versus groups 1 and 2 without effect of diet. In conclusion, the results provide evidence that light conditions influence diet induced changes in phenotypic traits like body weight gain, lipids as well as hormone levels (insulin and leptin) in WOKW rats.

Gene expression profile in bone of diabetes-prone BB/OK rats fed a high-fat diet.

A high-fat diet (HFD) has been recognized as a risk factor for diseases such as dyslipidemia, atherosclerosis, obesity, and osteoporosis. However, studies analyzing gene expression after HFD in bone are rare. That prompted us to analyze the expression of selected genes in bone of 4-week-old diabetes-prone B(io)B(reeding) rats. Two breeding pairs were fed a HFD (+10 % tallow) or were fed a normal diet (ND; Ssniff R-Z) before mating and afterward during pregnancy. After the birth of progeny, parents continued to be given HFD or ND until the progeny was weaned (3 weeks). Thereafter, offspring were weaned and were fed the same food as their parents up to an age of 4 weeks. Body weight was measured at an age of 4 weeks, and subsequently 13 HFD rats and 13 ND rats were killed and the tibial bone was harvested to analyze the expression of 53 genes in bone. All rats fed HFD were significantly heavier than rats fed ND after 3 and 4 weeks. The diet also influenced the expression of genes in bone. There were significant differences in 20 out of 53 genes studied between rats fed HFD compared with rats fed ND. Four out of 20 had a lower and 17 out of 20 genes a higher expression in HFD rats, but differences in gene expression showed obvious differences between males and females. There were only two genes that were similarly different between males and females: Bmp4 and Atf4. Two genes, Foxg1 and Npy, were inversely expressed in males and females. It seems that the gene expression is differently regulated by diet during pregnancy and later in life between males and females. Nevertheless, it cannot be excluded that HFD also acts as an epigenetic factor in the development of offspring in utero.

Histomorphometric and radiographical changes after lumbar implantation of the PEEK nonfusion interspinous device in the BB.4S rat model.

STUDY DESIGN: An experimental animal study. OBJECTIVE: To investigate histomorphometric and radiographical changes in the BB.4S rat model after PEEK (polyetheretherketone) nonfusion interspinous device implantation. SUMMARY OF BACKGROUND DATA: Clinical effectiveness of the PEEK nonfusion spine implant Wallis (Abbott, Bordeaux, France; now Zimmer, Warsaw, IN) is well documented. However, there is a lack of evidence on the long-term effects of this implant on bone, in particular its influence on structural changes of bone elements of the lumbar spine. METHODS: Twenty-four male BB.4S rats aged 11 weeks underwent surgery for implantation of a PEEK nonfusion interspinous device or for a sham procedure in 3 groups of 8 animals each: (1) implantation at level L4-L5; (2) implantation at level L5-L6; and (3) sham surgery. Eleven weeks postoperatively osteolyses at the implant-bone interface were measured via radiograph, bone mineral density of vertebral bodies was analyzed using osteodensitometry, and bone mineral content as well as resorption of the spinous processes were examined by histomorphometry. RESULTS.: Resorption of the spinous processes at the site of the interspinous implant was found in all treated segments. There was no significant difference in either bone density of vertebral bodies or histomorphometric structure of the spinous processes between adjacent vertebral bodies, between treated and untreated segments and between groups. CONCLUSION: These findings indicate that resorption of spinous processes because of a result of implant loosening, inhibit the targeted load redistribution through the PEEK nonfusion interspinous device in the lumbar spinal segment of the rat. This leads to reduced long-term stability of the implant in the animal model. These results suggest that PEEK nonfusion interspinous devices like the Wallis implants may have time-limited effects and should only be used for specified indications.

Phenotypic and gene expression differences between DA, BN and WOKW rats.

BACKGROUND: Because inbred rat strains are widely used as laboratory models, knowledge of phenotypic and genetic variations between strains will be useful to obtain insight into the relationship between different strains. METHODS AND RESULTS: We studied phenotypic traits: of each strain--BN/K, DA/K and WOKW--10 male rats were studied for body weight and serum constituents at an age of 10 and 30 weeks. In addition, a total of 95 rats were studied for life expectancy. At an age of 30 weeks, these male rats were killed by an overdose of anesthetic (Sevofluran, Abbott), and the subcutaneous and visceral adipose tissue as well as bone tissue were removed to study the expression of 20 genes. There were significant differences in body weight, serum lipids and leptin at an age of 30 weeks between strains. Regarding life expectancy, BN rats lived longest (1072±228d). The highest gene expression was found in bone of BN rats. In adipose tissues, Nfkb1 is only expressed in subcutaneous adipocytes, and 5 genes, Col2a1, Mmp9, Tnfa, Ins1 and Cyp24a1, are not expressed in adipocytes. The ranking BN = DA>WOKW was observed in only one gene in subcutaneous (Fto) and visceral adipocytes (Col6a1). There were no significant differences in gene expression of one gene in subcutaneous adipocytes and of 3 genes in visceral adipocytes. Comparing the gene expression in visceral and subcutaneous adipocytes, only one gene showed a comparable behavior (Bmp1). CONCLUSION: From these results, it can be concluded that obvious phenotypic differences are caused by genetic differences between three rat strains, BN, DA and WOKW, as supported by gene expression studies in bone and adipose tissues. Especially BN rats can be used to study the genetic basis of long life.

Gene expression profiling supports the role of Repin1 in the pathophysiology of metabolic syndrome.

Congenic BB rat strains carrying a SHR segment (D4Got41-Tacr1; 60.5-122.8 Mb; BB.4S) or a WOKW segment (D4Got41-Fabp1; 60.5-104.6 Mb; BB.4W) of chromosome 4 within the BB/OK background develop facets of the metabolic syndrome when compared with their parental BB/OK rats. To narrow down potential genes involved in the pathophysiology of metabolic syndrome, gene expression studies in adipose tissues of BB/OK, BB.4S, and BB.4W rats were initiated. Total RNA of subcutaneous and epididymal adipose tissue of BB/OK (n=10), congenic BB.4S (n=8), and BB.4W (n=9) males at an age of 4 weeks was isolated. The mRNA expression of 92 genes involved in obesity, insulin resistance and other metabolic traits was measured by RT-PCR. Significant differences in gene expression were only found in Repin1 in both adipose tissues. Congenic BB.4W showed significantly lower gene expression than did BB.4S and BB/OK. Our findings and newly published findings of Repin1 in 3T3-L1 adipocytes support the hypothesis that Repin1 may affect the development of facets of the metabolic syndrome.

Gender differences in Nociceptin/Orphanin FQ-induced food intake in strains derived from rats prone (WOKW) and resistant (Dark Agouti) to metabolic syndrome: a possible involvement of the cocaine- and amphetamine-regulated transcript system.

Our previous study found that when injected with Nociceptin/Orphanin FQ (N/OFQ) into the brain, male Dark Agouti (DA) rats, which are resistant to metabolic syndrome, have greater hyperphagia than male Wistar Ottawa Karlsburg W (WOKW) animals, which are prone to this disease. We attributed this difference to the fact that these two strains have different cocaine-amphetamine regulated transcript peptide (Cart) gene sequences and expression. In order to address this hypothesis, the present work focused on sex differences and analyzed not only male but also female N/OFQ-induced (0.25 and 0.5 nmol/rat) food intake in terms of their Cart and N/OFQ receptor gene expression in the hypothalamic area. In N/OFQ-naive WOKW females, cart gene expression is extremely elevated compared to N/OFQ-naive WOKW males. When male and female WOKW littermates are stimulated with N/OFQ, the food intake of females is significantly lower than that of the males. Granted, the N/OFQ feeding behavior experiments were not performed on the animals measured for Cart gene expression, but nonetheless, the responses observed in littermates point to an interesting avenue for further inquiry.

High-fat diet protects BB/OK rats from developing type 1 diabetes.

BACKGROUND: It is well known that lipid metabolism plays an important role in the early stages of type 1 diabetes (T1D). For that reason, we examined factors that influence lipid metabolism of BioBreeding/Ottawa Kalsburg (BB/OK) rats that spontaneously develop an insulin-dependent T1D. METHODS: BB/OK female rats were fed a high-fat diet during pregnancy (Ssniff R-Z + 10% tallow) and their progeny were also given this diet up to an age of 30 weeks (n = 55) or 4 weeks (n = 14) to study gene expression of Pparg, Fasn, Lep, Adipoq, Repin1, Rarres 2, and Glut4 in adipose tissue. Forty-two BB/OK rats fed the normal diet (Ssniff R-Z) during pregnancy and the observation period served as controls. RESULTS: The high-fat diet significantly decreased diabetes frequency in BB/OK rats when compared with control rats (71 versus 95%, p = 0.002). Although this difference was also reflected in the male rats (68 versus 100%, p = 0.003), no significant variation was observed in female rats (73 versus 90%, p = 0.23). The high-fat diet resulted in significantly reduced mRNA expression of examined genes in subcutaneous adipose tissue, but not in visceral adipose tissue, except for Fasn and Repin1 expression. CONCLUSIONS: A high-fat diet seems to protect BB/OK rats from T1D in a sex-specific manner. The data suggest that a high-fat diet might influence fat accumulation and/or fat metabolism and prevent T1D development in male rats, which is supported by changes in adipose tissue gene expression.

Transplantation of adipose tissue protects BB/OK rats from type 1 diabetes development.

B(io) B(reedding)/O(ttawa) K(alsburg) rats spontaneously develop insulin-dependent type 1 diabetes. Days before BB/OK rats become diabetic, their body seems to be flabby which may be attributed to loss of subcutaneous fat. However, the rats are normoglycemic and manifest 3-4 days later. This observation prompted us to search for possibilities to avoid the loss of adipose tissue. BB/OK rats were subcutaneously grafted with visceral adipose tissue. In total, 34 (71%) out of 48 male and 23 (49%) out of 47 female BB/OK rats grafted with adipose tissue developed type 1 diabetes so that significantly more females than males were protected from diabetes development (p=0.03). In the control group, 17 (85%) out of 20 male and 20 (95%) out of 21 female BB/OK rats were diabetic. Adipose tissue transplantation can protect BB/OK rats from type 1 diabetes development in a sex specific manner. One could conclude that the manipulations have influenced fat accumulation and/or fat metabolism which prevent type 1 diabetes development in about 50% of BB/OK rats. This idea is supported by the finding that a mutation in the leptin receptor of NOD mice suppresses type 1 diabetes progression.

Influence of glycemic control on tympanic membrane healing in diabetic rats.

OBJECTIVES/HYPOTHESIS: It is generally assumed that glycemic control in diabetic patients is important in optimizing wound healing. The goal of this study was to examine tympanic membrane (TM) wound healing in spontaneously diabetic rats depending on the diabetic metabolic state compared to nondiabetic control animals. STUDY DESIGN: Prospective controlled study in experimental animals. METHODS: Right-sided myringotomy was performed in 20 normoglycemic rats, 17 well-compensated, and 23 poorly compensated diabetic rats. TMs were observed for a total of 3 weeks. Effect of diabetic metabolic state on the healing of the TMs was evaluated by closure rates and histology. RESULTS: Diabetic rats showed a significant delay in TM wound healing compared to the control group, but there were no significant differences between both diabetes groups. CONCLUSIONS: Glycemic control does not influence TM wound repair in an animal model of type 1 diabetes.

Repin1 maybe involved in the regulation of cell size and glucose transport in adipocytes.

Replication initiator 1 (Repin1) is highly expressed in liver and adipose tissue and has been suggested as candidate gene for obesity and its related metabolic disorders in congenic and subcongenic rat strains. The cellular localization and function of Repin1 has remained elusive since its discovery in 1990. To characterize the role of Repin1 in adipocyte biology, we used siRNA knockdown technology to reduce the expression of Repin1 by electroporation of semiconfluent 3T3-L1 preadipocytes. Glucose transport, palmitate uptake as well as triglyceride content were measured. In paired samples of human visceral and subcutaneous adipose tissue, we investigated whether Repin1 mRNA expression is related to measures of fat accumulation and adipocyte size. We demonstrate that Repin1 increases during adipogenesis. RNA interference based Repin1 downregulation in mature adipocytes significantly reduces adipocyte size and causes reduced basal, but enhanced insulin stimulated glucose uptake into 3T3-L1 cells. Additionally, knockdown of Repin1 resulted in reduced palmitate uptake and significantly changed the mRNA expression of genes involved lipid droplet formation, adipogenesis, glucose and fatty acid transport. Furthermore, we found significant correlations between Repin1 mRNA expression in human paired visceral and subcutaneous adipose tissue and total body fat mass as well as adipocyte size. We have identified a potential role for Repin1 in the regulation of adipocyte size and expression of glucose transporters GLUT1 and GLUT4 in adipocytes.

Type 1 diabetes in BioBreeding rats is critically linked to an imbalance between Th17 and regulatory T cells and an altered TCR repertoire.

Diabetes-prone BioBreeding (DP-BB) rats spontaneously develop type 1 diabetes mellitus (T1DM) on grounds of their MHC haplotype RT1(u) and a point mutation in the Gimap5 gene. In this study, we report that DP-BB rats exhibit an increasingly severe imbalance, in particular between Th17 and regulatory T (T(reg)) cells, within the first months of age. This can be assigned to an excess in effector T cells because neither the percentage nor the function of the T(reg) cells is compromised. Flow cytometric analysis of Vbeta segment usage and CDR3 spectratyping further suggest that the disturbed repertoire of peripheral T cells may also contribute to the development of T1DM in DP-BB rats. Importantly, expansion of T(reg) cells in vivo by means of a CD28 superagonistic Ab as well as adoptive transfer of T(reg) cells efficiently interferes with the development of T1DM in DP-BB rats, whereas treatment with conventional Th cells does not afford protection. Using a newly generated strain of enhanced GFP transgenic rats, we could further demonstrate that the transferred T(reg) cells persist in the recipient rats for several months and partially correct the imbalance between Th17 and T(reg) cells. Thus, our data support the hypothesis that unchecked effector T cell action and a disturbed T cell repertoire contribute to the development of T1DM in DP-BB rats, which may also have implications for a better understanding of the human disease.

Genes on rat chromosomes 3, 5, 10, and 16 are linked with facets of metabolic syndrome.

WOKW (Wistar Ottawa Karlsburg W) rats develop metabolic syndrome closely resembling human disorder. In crossing studies between disease-prone WOKW and disease-resistant DA (Dark Agouti) rats, several quantitative trait loci (QTLs) were mapped. To prove the in vivo relevance of QTLs, congenic DA.WOKW rats, briefly termed DA.3aW, DA.3bW, DA.5W, DA.10W, and DA.16W, were generated by transferring chromosomal regions of WOKW chromosomes 3, 5, 10, and 16 onto DA genetic background. Male (n=12) and female (n=12) rats of each congenic strain and their parental strain DA were characterized for adiposity index (AI), serum leptin, and serum insulin as well as serum cholesterol and serum triglycerides as single facets of metabolic syndrome at the age of 30 weeks. The data showed a significant higher AI for male and female DA.3aW and female DA.16W compared with DA. Serum leptin was significantly elevated in male and female DA.3aW, DA.10W, and DA.16W rats in comparison with DA. Rats of both sexes of DA.10W and female DA.16W showed significantly elevated serum insulin in comparison to DA. Female rats of all congenics had significantly higher serum cholesterol compared with DA, while males did not differ. Finally, triglycerides were only elevated in male DA.16W. The results demonstrate an involvement of WOKW chromosomes 3, 5, 10, and 16 in developing facets of the metabolic syndrome.

Multidrug resistance-related protein 2 genotype of the donor affects kidney graft function.

OBJECTIVES: We tested the effect of kidney-specific multidrug resistance-related protein (MRP2, ABCC2) deficiency on renal organic solute disposition as well as on renal protein and gene expression. Furthermore, we investigated whether a particular kidney donor ABCC2 genotype is associated with delayed graft function in patients. METHODS: A new MRP2-deficient rat strain was established. Renal cross-transplantations were performed between congenic MRP2-deficient and wild-type rats. Renal disposition of MRP2 substrates was investigated in native and transplanted rats. Proteomic analyses and transcriptional profiling were performed in rat kidney graft cortices. Ninety-eight human kidney donor-recipient pairs were genotyped for five ABCC2 polymorphisms. The relationship between delayed graft function and ABCC2 genetic variants in donors and recipients was analyzed by backward stepwise logistic regression. RESULTS: In rats, the absence of renal MRP2 reduced renal bilirubin glucuronide excretion at pathologic plasma concentrations, modified renal p-aminohippurate excretion and did not affect renal morphine-6-glucuronide excretion. Renal MRP2 deficiency led to renal cortical protein or mRNA upregulation of glutathione transferase isoenzymes, glutaredoxin 2, and heme oxygenase-1. In patients, a particular donor ABCC2 genotype was associated with an increased incidence of delayed graft function. CONCLUSION: Kidney graft-specific MRP2 deficiency has mild effects on the renal excretion of some organic solutes under experimental conditions and induces a protein and gene expression pattern indicative of activated antioxidant defense mechanisms. This suggests that MRP2 is a determinant of the redox status in tubular epithelial cells and thus of the susceptibility to renal damage under conditions of treatment with multiple drugs and increased oxygen radical formation.

Nociceptin/orphanin FQ-induced food intake and cocaine amphetamine regulated transcript gene expression in strains derived from rats prone (WOKW) and resistant (Dark Agouti) to metabolic syndrome.

In previous work, we observed that N/OFQ-induced hyperphagia is greater in DA rats, animals resistant to metabolic syndrome, than in WOKW animals, which are prone to this disease. We attributed this difference to the fact that these two strains have different Cart gene sequences and expression. As a preliminary approach to pursue this hypothesis, the present work focused on Cart gene expression by developing from DA and WOKW rats various congenic animals with exchanges of metabolic syndrome-related QTL's of different chromosomes (3, 5, 10 and 16), and analyzing their N/OFQ-induced (2.1, 4.2, and 8.4nmol/rat) food intake in terms of their CART gene expression and N/OFQ hypothalamic immunostaining. Two groupings emerged, the first, with strains 3a, 3b, and 5a with elevated N/OFQ-induced feeding similar to that of the DA rats, and the second, with strains 16 and 10, with lower feeding, like the WOKW rats. There was a perfect correlation between Cart gene expression and N/OFQ-induced feeding data at 30min for the strains DA, 3a, 3b, 5 in the first group, and 16 and WOKW for the second, but not for strain 10. As expected, the strains with low content of Cart gene expression had elevated N/OFQ-induced feeding, but contrary to expectations, strain 10, with the lowest Cart gene expression, exhibited low N/OFQ-induced feeding, on the order of that of the WOKW rats. A comparable trend was observed with N/OFQ hypothalamic immunostaining. This anomaly may be due to other satiety-related factors involved in N/OFQ-induced feeding.

Mild systemic inflammation has a neuroprotective effect after stroke in rats.

Stroke is accompanied by a strong inflammatory reaction in the brain. Periodontal disease is a chronic local infection which causes a systemic low grade inflammation. We hypothesized that a mild systemic inflammatory reaction as caused by periodontal disease prior to stroke onset, may exert a neuroprotective effect in a rat model of focal ischemia. To test this hypothesis, marginal periodontitis was induced by ligatures on the second maxillary molars in BB/LL Wistar rats for 3 weeks. Two weeks after periodontitis initiation, focal cerebral ischemia was produced by reversible occlusion of the right middle cerebral artery. After a survival time of 7 days after ischemia, rats were killed and bone loss was determined on the buccal and palatinal surfaces of the defleshed jaw. In addition, markers of systemic inflammation were determined in a different group of laboratory animals at 14 days after the onset of periodontitis. The infarct size and markers of the inflammatory reaction in the brain were determined by immunohistochemistry. We found: (i) rats with ligatures exhibited significantly more periodontal bone loss than the control rats; (ii) the development of periodontitis was associated with an elevated gene expression for several markers of systemic inflammation (interleukin-10, transforming growth factor beta 1, tumor necrosis factor alpha, interleukin-1beta and interferon gamma; (iii) rats with periodontitis and a mild systemic inflammation had a significantly reduced infarct volume and a significant reduction in the number of brain macrophages in the infarcted area. In conclusion we found that mild systemic inflammation elicited prior to stroke onset may have a neuroprotective effect in rats by reducing the infarct volume and tissue destruction by brain macrophages.