Moderate physical training increases brain insulin concentrations in experimental diabetic rats

Insulin is an important modulator of growth and metabolic function in the central nervous system. The aim of this study was to investigate the influence of swimming physical training (at 32̈±1̈C, 1 hr/day, 5 days/week, with an overload equivalent to 5% of the body weight, for 4 weeks) on brain insulin concentrations in alloxan induced type 1 diabetic rats. Training attenuated hyperglycemia but had no effect on insulinemia in diabetic rats. Hematocrit and blood albumin values remained without changes. Brain insulin did not change in diabetic rats. However, physical training increased the concentration in both control and diabetic rats. It is concluded that in the present experimental conditions, diabetes had no influence on brain insulin, however moderate physical training increased the hormone in both control and diabetic animals.

Spatio-temporal distribution of fatty acid-binding protein 6 (fabp6) gene transcripts in the developing and adult zebrafish (Danio rerio)

We have determined the structure of the fatty acid-binding protein 6 (fabp6) gene and the tissue-specific distribution of its transcripts in embryos, larvae and adult zebrafish (Danio rerio). Like most members of the vertebrate FABP multigene family, the zebrafish fabp6 gene contains four exons separated by three introns. The coding region of the gene and expressed sequence tags code for a polypeptide of 131 amino acids (14 kDa, pI 6.59). The putative zebrafish Fabp6 protein shared greatest sequence identity with human FABP6 (55.3%) compared to other orthologous mammalian FABPs and paralogous zebrafish Fabps. Phylogenetic analysis showed that the zebrafish Fabp6 formed a distinct clade with the mammalian FABP6s. The zebrafish fabp6 gene was assigned to linkage group (chromosome) 21 by radiation hybrid mapping. Conserved gene synteny was evident between the zebrafish fabp6 gene on chromosome 21 and the FABP6/Fabp6 genes on human chromosome 5, rat chromosome 10 and mouse chromosome 11. Zebrafish fabp6 transcripts were first detected in the distal region of the intestine of embryos at 72 h postfertilization. This spatial distribution remained constant to 7-day-old larvae, the last stage assayed during larval development. In adult zebrafish, fabp6 transcripts were detected by RT-PCR in RNA extracted from liver, heart, intestine, ovary and kidney (most likely adrenal tissue), but not in RNA from skin, brain, gill, eye or muscle. In situ hybridization of a fabp6 riboprobe to adult zebrafish sections revealed intense hybridization signals in the adrenal homolog of the kidney and the distal region of the intestine, and to a lesser extent in ovary and liver, a transcript distribution that is similar, but not identical, to that seen for the mammalian FABP6/Fabp6 gene. © 2008 The Authors.

Localization of myosin-Va in subpopulations of cells in rat endocrine organs

Myosin-Va is a Ca 2+/calmodulin-regulated unconventional myosin involved in the transport of vesicles, membranous organelles, and macromolecular complexes composed of proteins and mRNA. The cellular localization of myosin-Va has been described in great detail in several vertebrate cell types, including neurons, melanocytes, lymphocytes, auditory tissues, and a number of cultured cells. Here, we provide an immunohistochemical view of the tissue distribution of myosin-Va in the major endocrine organs. Myosin-Va is highly expressed in the pineal and pituitary glands and in specific cell populations of other endocrine glands, especially the parafollicular cells of the thyroid, the principal cells of the parathyroid, the islets of Langerhans of the pancreas, the chromaffin cells of the adrenal medulla, and a subpopulation of interstitial testicular cells. Weak to moderate staining has been detected in steroidogenic cells of the adrenal cortex, ovary, and Leydig cells. Myosin-Va has also been localized to non-endocrine cells, such as the germ cells of the seminiferous epithelium and maturing oocytes and in the intercalated ducts of the exocrine pancreas. These data provide the first systematic description of myosin-Va localization in the major endocrine organs of rat. © 2008 Springer-Verlag.

Alterações reprodutivas em ratos machos expostos perinatalmente aos frutos da Solanum lycocarpum

This work employed pregnant rats treated with Solanum lycocarpum unripe fruits (10% in diet) from gestation day (GD) 06 to post-natal day (PND) 07, for the evaluation of the sperm number, daily sperm production and epididymal sperm transit time of the male offspring at PND 60 and PND 90. No differences were observed in the daily sperm production (DSP) and sperm number in the testis of the exposed males at PND 60 and PND 90. Also, no alterations were observed in sperm transit time in the caput epididymis of the exposed males at PND 60 and PND 90. However, a reduced sperm transit time was observed in the corpus/cauda epididymis of the experimental males at PND 90. The last data may explain the reduced sperm number observed in the corpus/cauda epididymis of the experimental male rats at PND 90. These data show that the male rats exposed to S. lycocarpum fruits during gestation did not present alterations in testis sperm production and number, however the sperm transit time through epididymis was impaired, resulting in a decreased number of spermatozoa in epididymis cauda. We conclude that S. lycocarpum may cause imbalance on hypothalamus-pituitary gland axis.

Amifostine reduces the seminiferous epithelium damage in doxorubicin-treated prepubertal rats without improving the fertility status

Background: Amifostine is an efficient cytoprotector against toxicity caused by some chemotherapeutic drugs. Doxorubicin, a potent anticancer anthracycline, is known to produce spermatogenic damage even in low doses. Although some studies have suggested that amifostine does not confer protection to doxorubicin-induced testicular damage, schedules and age of treatment have different approach depending on the protocol. Thus, we proposed to investigate the potential cytoprotective action of amifostine against the damage provoked by doxorubicin to prepubertal rat testes (30-day-old) by assessing some macro and microscopic morphometric parameters 15, 30 and 60 days after the treatment; for fertility evaluation, quantitative analyses of sperm parameters and reproductive competence in the adult phase were also carried out.Methods: Thirty-day-old male rats were distributed into four groups: Doxorubicin (5 mg/kg), Amifostine (400 mg/kg), Amifostine/Doxorubicin (amifostine 15 minutes before doxorubicin) and Sham Control (0.9% saline solution). Standard One Way Anova parametric and Anova on Ranks non-parametric tests were applied according to the behavior of the obtained data; significant differences were considered when p < 0.05.Results: The rats killed 30 and 60 days after doxorubicin treatment showed diminution of seminiferous epithelium height and reduction on the frequency of tubular sections containing at least one type of differentiated spermatogonia; reduction of sperm concentration and motility and an increase of sperm anomalous forms where observed in doxorubicin-treated animals. All these parameters were improved in the Amifostine/Doxorubicin group only when compared to Doxorubicin group. Such reduction, however, still remained below the values obtained from the Sham Control group. Nevertheless, the reproductive competence of doxorubicin-treated rats was not improved by amifostine pre-administration.Conclusions: These results suggest that amifostine promotes a significant reduction of the doxorubicin long-term side effects on the seminiferous epithelium of prepubertal rats, which is reflected in the epidydimal fluid parameters in the adult phase. However, fertility status results suggest that such protection may not be effective against sperm DNA content damage. Further investigation of sperm DNA integrity must be carried out using amifostine and doxorubicin-treated experimental models. © 2010 Vendramini et al; licensee BioMed Central Ltd.

Chronic alcohol intake upregulates hepatic expression of carotenoid cleavage enzymes and PPAR in rats

Excessive and chronic alcohol intake leads to a lower hepatic vitamin A status by interfering with vitamin A metabolism. Dietary provitamin A carotenoids can be converted into vitamin A mainly by carotenoid 15,15′-monooxygenase 1 (CMO1) and, to a lesser degree, carotenoid 9′10′-monooxygenase 2 (CMO2). CMO1 has been shown to be regulated by several transcription factors, such as the PPAR, retinoid X receptor, and thyroid receptor (TR). The regulation of CMO2 has yet to be identified. The impact of chronic alcohol intake on hepatic expressions of CMO1 and CMO2 and their related transcription factors are unknown. In this study, Fischer 344 rats were pair-fed either a liquid ethanol Lieber-DeCarli diet (n = 10) or a control diet (n = 10) for 11 wk. Hepatic retinoid concentration and expressions of CMO1, CMO2, PPARγ, PPARα, and TRβ as well as plasma thyroid hormones levels were analyzed. We observed that administering alcohol decreased hepatic retinoid levels but increased mRNA concentrations of CMO1, CMO2, PPARγ, PPARα, and TRβ and upregulated protein levels of CMO2, PPARγ, and PPARα. There was a positive correlation of PPARγ with CMO1(r = 0.89; P<0.0001) and both PPARγ and PPARα with CMO2 (r = 0.72, P< 0.001 and r = 0.62, P< 0.01, respectively). Plasma thyroid hormone concentrations did not differ between the control rats and alcohol-fed rats. This study suggests that chronic alcohol intake significantly upregulates hepatic expression of CMO1 and, to a much lesser extent, CMO2. This process may be due to alcohol-induced PPARγ expression and lower vitamin A status in the liver. © 2010 American Society for Nutrition.

Exercise training ameliorates the impairment of endothelial and nitrergic corpus cavernosum responses in diabetic rats

Aims: The effect of exercise training (ET) on vascular responsiveness in diabetes mellitus has been largely well studied. However, limited studies have investigated the effects of ET on functional responses of the corpus cavernosum (CC) in diabetic animals. Therefore, the aim of this study was to investigate whether prior ET prevents the impairment of erectile function in streptozotocin-induced diabetic rats. Main methods: Rats were exercised for four weeks prior to the induction of diabetes, and then again for another 4 weeks thereafter. Concentration-response curves to acetylcholine, sodium nitroprusside, Y-27632, BAY 412272 and phenylephrine (PE) were obtained in CC. The excitatory and inhibitory effects of electrical-field stimulation were also evaluated. Key findings: Plasma SOD levels were markedly decreased in the sedentary diabetic group (D-SD) as compared to control sedentary animals (C-SD), approximately 53% (P < 0.05) and this reduction was restored in trained diabetic animals. Physical training restored the impairment of endothelium-dependent and -independent relaxation responses seen in the D-SD group. The potency values for Y-27632 in the CC were significantly reduced in the D-SD group, which was reversed by physical training. The impairment of electrical-field stimulation (EFS)-induced relaxation seen in the D-SD group was restored by physical training. On the other hand, both EFS-induced contractions and concentration-response curves to PE in cavernosal strips were not modified by either diabetes or physical training. Significance: Practice of regular physical exercise may be an important approach in preventing erectile dysfunction associated with diabetes mellitus by re-establishment of the balance between NO production and its inactivation. © 2010 Elsevier Inc. All rights reserved.

Perinatal exposure to parasiticide ivermectin: Long-term effects on reproductive parameters of adult male rats

Ivermectin is one of the most widely used antiparasitic drugs globally. The aim of this study was to evaluate the chronic effects of perinatal exposure to ivermectin on male reproductive parameters in rats. Pregnant rats were treated daily by oral gavage with 0.4 or 1.6 mg kg -1 of ivermectin or vehicle, from gestational day 6 until post-natal day 10. In the adulthood stage, there were significant reductions in the relative testicular weight of rats exposed to the low dose and in relative prostate weight of male rats exposed to the high dose of ivermectin. Furthermore, the animals exposed to the low dose also presented an increased seminal vesicle weight compared to controls. However, neither of the ivermectin doses interfered in daily sperm production, sperm number in testis, or sexual behavior of exposed males. In conclusion, perinatal exposure to ivermectin neither altered the male reproductive system development markedly, nor produced any adverse effects on the parameters evaluated. © 2011 Taylor & Francis.

Long-term ethanol consumption promotes hepatic tumorigenesis but impairs normal hepatocyte proliferation in rats

Chronic and excessive alcohol consumption has been related to an increased risk of several cancers, including that of the liver; however, studies in animal models have yet to conclusively determine whether ethanol acts as a tumor promoter in hepatic tumorigenesis. We examined whether prolonged alcohol consumption could act as a hepatic tumor promoter after initiation by diethylnitrosamine (DEN) in a rat model. Male Sprague-Dawley rats were injected with 20 mg DEN/kg body weight 1 wk before introduction of either an ethanol liquid diet or an isoenergic control liquid diet. Hepatic pathological lesions, hepatocyte proliferation, apoptosis, PPARα and PPARγ, and plasma insulin-like growth factor 1 (IGF-1) levels were assessed after 6 and 10 mo. Mean body and liver weights, plasma IGF-1 concentration, hepatic expressions of proliferating cellular nuclear antigen and Ki-67, and cyclin D1 in ethanol-fed rats were all significantly lower after 10 mo of treatment compared with control rats. In addition, levels of hepatic PPARγ protein, not PPARα, were significantly higher in the ethanol-fed rats after prolonged treatment. Although ethanol feeding also resulted in significantly fewer altered hepatic foci, hepatocellular adenoma was detected in ethanol-fed rats at 10 mo, but not in control rats given the same dose of DEN. Together, these results indicate that chronic, excessive ethanol consumption impairs normal hepatocyte proliferation, which is associated with reduced IGF-1 levels, but promotes hepatic carcinogenesis. © 2011 American Society for Nutrition.

Histochemical and ultrastructural analysis of hepatic glycogen and collagen fibers in alloxan-induced diabetic rats submitted to long-term physical training

Alterations in liver functions are common among diabetic patients, and many symptoms in the liver have been reported, including changes in glycogen stores and in the amount of collagen fibers. The practice of physical training and its morphological effects in this organ, however, are scarcely studied. In order to observe the morphological effects of alloxan-induced diabetes and the alterations arising from the practice of long-term chronic physical training in the liver, samples were collected and processed, and then analyzed by means of the histochemical techniques Periodic Acid-Schiff and Picrosirius-Hematoxylin, and ultrastructural cytochemical test of Afzelius. Through evaluation of the tissue, it was observed a drastic reduction in hepatic glycogen stores of sedentary diabetics, recovered in trained diabetic rats. Furthermore, it was detected a decrease in the content of perisinusoidal collagen fibers in the diabetic liver, also recovered due to the development of a training protocol. On ultrastructural level, cytochemical analysis confirmed the loss of glycogen and the recovery obtained by training. In conclusion, the practice of a long-term chronic physical training protocol may be considered an important assistant in the treatment of diabetes, mitigating the occurrence of possible damages to liver tissue. © 2011 Elsevier Ltd.

Avaliação morfométrica dos hepatócitos de ratos diabéticos tratados com neem (azadirachta indica a. juss) e estreptozootocina 6 ch

The effects of extracts from Azadirachta indica A. Juss and streptozotocin, in extreme high dilutions in dinamized systems, on hepatocyte morphometry of rats with diabetes mellitus induced by streptozotocin were evaluated. Some parameters presented significant differences among the experimental groups, but the effect of treatments to make better or worse the consequences of diabetes mellitus on liver was not detected using only the hepatocyte morphometry. The morphometric analysis evidenced that the white control group presented the highest mean values for nucleus and cytoplasm parameters, with the exception of the nuclear shape factor. However, this situation did not imply the diabetes mellitus was the cause of drastic reduction in these values, since the literature describes lower measurements for rats from the control group (non-diabetic rats).

The expression of aquaporins 1 and 9 in adult rat epididymis is perturbed by chronic exposure to ethanol

Aquaporins (AQPs), notably AQP-1 and AQP-9, may contribute to reabsorption of fluid and solute across the epididymis. Ethanol is related to be a toxicant affecting directly or indirectly the epididymis and the sperm motility. This study examined the expression of AQP-1 and AQP-9 in adult epididymis of the UChA and UChB 10% (v/v) ethanol-preferring rats, focusing the ethanol-induced hormonal disturbances upon the regulation of these AQPs. Chronic ethanol intake significantly decreased body weight, while UChA and UChB rats displayed a marked loss of epididymal weights. Both ethanol-consuming animals had a severe reduction of testosterone levels, whereas LH and 17β-estradiol were unchanged. Throughout the epididymis, a strong reaction to AQP-1 was observed in myoid and endothelial cells of the UChB ethanol-preferring rats, differently from a moderate intensity in the initial segment of the UChA rats. In addition, AQP-9 showed a strong immunoreaction in the apical membrane of principal cells at initial segment. In cauda epididymis, the level of AQP-9 was reduced along the microvillus projections in both UChA and UChB rats compared to controls. We conclude that chronic ethanol consumption modulates the androgen levels, thereby modifying the expression pattern of AQP-1 and 9 in the epididymis. © 2011 Elsevier Ltd.

Baccharis dracunculifolia, the main source of green propolis, exhibits potent antioxidant activity and prevents oxidative mitochondrial damage

Baccharis dracunculifolia DC (Asteraceae) is the main botanical source used by honeybees to produce Brazilian green propolis whose hepatoprotective properties have been already described. In this work we investigated the protective effects of the glycolic extract of B. dracunculifolia (GEBd) against oxidative stress in isolated rat liver mitochondria (RLM). The GEBd was prepared by fractionated percolation using propylene glycol as solvent. The total phenols and flavonoids, which are substances with recognized antioxidant action, were quantified in GEBd and the phytochemical analysis was carried out by HPLC. GEBd exhibited significant scavenger activity towards DPPH radicals and superoxide anions in a concentration-dependent manner, and also a Fe 2+ chelating activity. GEBd decreased the basal H 2O 2 generation and the Fe 2+- or t-BuOOH-induced ROS production in isolated mitochondria. Lipid oxidation of mitochondrial membranes, protein thiol groups and GSH oxidation were also prevented by GEBd. This shows that B. dracunculifolia exhibit potent antioxidant activity protecting liver mitochondria against oxidative damage and such action probably contribute to the antioxidant and hepatoprotective effects of green propolis. © 2011 Elsevier Ltd.

Employment of a noninvasive magnetic method for evaluation of gastrointestinal transit in rats

AC Biosusceptometry (ACB) was previously employed towards recording gastrointestinal motility. Our data show a reliable and successful evaluation of gastrointestinal transit of liquid and solid meals in rats, considering the methods scarcity and number of experiments needed to endorsement of drugs and medicinal plants. ACB permits real time and simultaneous experiments using the same animal, preserving the physiological conditions employing both meals with simplicity and accuracy. © 2012 Quini et al.; licensee BioMed Central Ltd.

Nutritional evaluation of soy yoghurt in comparison to soymilk and commercial milk yoghurt. Effect of fermentation on soy protein

Soymilk was fermented using Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus. The soy yoghurt produced was evaluated in comparison to soymilk and commercial milk yoghurt by biological evaluation, rat growth, nitrogen balance assays and microbiological methods. Trypsin inhibitor activity and chemical composition were also determined for all samples. For the soy yoghurt, the growth and nitrogen balance values were not different from the control diet, but the nitrogen balance values were higher than for the soymilk, without significant difference in terms of growth assays. Compared to the commercial yoghurt, Net Protein Ratio and Nitrogen Utilization values were lower, but the Protein Efficiency Ratio, Biological Value and Net Protein Utilization values were equivalent, and for digestibility assays the best results were obtained with the soy yoghurt. The results indicated that soy yoghurt represents a good protein alternative to milk yoghurt and casein. The protein quality of soymilk evidently increased during the fermentation process using Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus, including a reduction in trypsin inhibitor levels of about 30%.