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Little is known about the in vivo influence of the blockade of the growth hormone secretagogue receptor Ia (GHS-R1a) on the gut structure. Data obtained in in vitro studies can be misinterpreted and can generate a confusing picture of the effects of ghrelin on the gastrointestinal structure. In a living organism the remodeling processes in the gastrointestinal tract is affected by complex regulatory mechanisms governed by locally produced hormones and peptides, as well as by the enteric and central nervous system. To our knowledge, there are as yet no published reports on the influence of ghrelin receptor blockades on the morphology of the alimentary system. The aim of the study was therefore to determine the effect of the GHS-R1a antagonist [D-Lys3]-GHRP-6 on the structure of the gastrointestinal (GI) system in the rat. Studies were performed on 12 male Wistar rats aged approx. 2 months with an initial body mass of approx. 180-200 g. The rats were kept on a 12/12 hour light/dark cycle at a temperature of 22 ± 2°C, and had free access to a standard rat diet and water. The animals were divided into two groups: control and experimental. The control group received physiological saline, and the experimental group were administered 100 nmol/kg b.wt. of [D-Lys3]-GHRP-6, a GHS-R1a antagonist (Peptides International, USA&Canada), intragastrically one dose/day during 4 weeks. The animals were fasted during the night before killing. After euthanasia the GI tract was rapidly removed, and the weight and length of the stomach, pancreas, liver, and small intestine were measured. Samples of the pancreatic tissue, duodenum, jejunum (25%, 50%, 75% of length), and ileum were taken for histological analyses. The paraffin sections were stained with hematoxylin and eosin, and a morphometric analysis was performed with the use of light microscopy. Significant differences in the surface area of pancreatic acinar cells and significantly increased mucosa thickness, villi length and crypt depth in the proximal jejunum were found in the rats intragastrically treated with [D-Lys3]-GHRP-6. However, changes in body weight, weight of the organs, and intestine length were not significant. In conclusion, the blockade of the GHS-R1a by [D-Lys3]-GHRP-6 did not abolish the pro-proliferative effect of endogenous ghrelin on the intestinal mucosa in the proximal jejunum, and increased the surface area of pancreatic acinar cells. The mechanisms behind these changes are not fully understood, and further research is needed for a better understanding of this phenomenon.
Calbindin (CB) is a calcium binding protein playing a role in calcium uptake and anti-apoptotic cellular protection. The expression of CB was immunohistochemically studied in the small intestine of normal and red bean kidney lectin-treated suckling piglets. In the duodenum and jejunum (but not ileum) of lectin-treated animals overexpression of CB was noted in chromogranin A-immunoreactive (CgA-IR) neuroendocrine (NE) cells. In both control and experimental group a small population of CB-IR NE cells exhibited the presence of somatostatin (but not serotonin, histamine or CRF). After the lectin treatment, an increased (however not statistically significant) immunoreactivity to CB was found in a small subpopulation of neurons of outer submucous (but not inner submucous and myenteric) plexus. It is suggested that there is a functional interaction between lectin administration and CB-expression in the porcine small intestine. Future studies will be needed to clarify this processes.
A total of ninety white storks (Ciconia ciconia) of both sexes aged over one year of life and at a body weight between 2.8-4.15 kg were subjects for observations. They were collected from the Warmia and Masuria region, and were rehabilitees of The Wild Birds Rehabilitation Center (Bukwald, Poland). The storks formed a group of birds that had wing damage like broken bones and were unable to fly. According to the severity of the case storks underwent three different kinds of treatment. Light cases of motion disability were submitted to wing or leg stabilization with adhesive bandages (treatment I), while middle and severe cases were additionally submitted to the administration of one (treatment II) or two capsules (treatment III) of propolis and pollen bee preparation (Apipol Farma’s Propolis Plus®) for two weeks, respectively. After the convalescence period a total of twenty three white storks did not recover and were euthanized and dissected. Post mortem samples of pectoral and femoral muscles as well as liver and kidney samples were taken. Mercury concentration was analyzed and the results revealed that the level in the kidneys and liver of white storks not receiving propolis preparation were significantly higher than that of those from treatment II and III. Contrary to this, the mercury concentration recorded in the pectoral and femoral muscles of the birds of treatment II and treatment III were significantly higher than that of the treatment without propolis preparation. The results showed that propolis and pollen bee preparation can reduce the level of mercury in kidneys and liver, but has no influence on the reduction of mercury in pectoral and femoral muscles.
Modifications in the structure of gastrointestinal mucosa is often used to evaluate gut function for instance during the development or in response to particular food components. Scanning electron microscopy (SEM) gives a chance to observe the surface of the gut epithelium in three dimensions. However, this technique is seldom used due to technical difficulties. The present study attempted to investigate the intestinal mucosa structure changes in the postnatal pig using light and scanning electron microscopy technique. Experiments were carried out on sow reared piglets from birth until 38 days of age. Piglets were sacrificed at birth and at the 3rd, 7th, 21st and 38th day of life. The entire gastrointestinal tract was immediately harvested and the whole thickness tissue samples were taken from the duodenum, jejunum and ileum for optical and scanning electron microscopy. SEM analyses corroborated with histometry made by optical microscopy. Moreover, a number of shape modifications of the villi and its surface have been observed. The development changes in small intestine mucosa during the first 3 weeks were manifested in shape, size and density of villi. In conclusion, the structure of small intestinal mucosa undergoes profound structural changes. SEM gives a new dimension in the investigation of gut mucosa.
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