Effects of Ghrelin on the Oxidative Stress and Healing of the Colonic Anastomosis in Rats.

BACKGROUND: Anastomotic leakage is the deadliest complication of colonic procedures. Ghrelin is an orexigenic hormone with potent actions on growth hormone release and functions in the processes of growth, tissue inflammation, repair, and oxidative stress. We evaluated the hypothesis that the exogenous administration of ghrelin causes beneficial effects on the healing of colonic anastomosis. MATERIALS AND METHODS: Sixty-four male Wistar rats were randomly assigned to eight subgroups receiving postoperative intraperitoneal administration of ghrelin (23 µg/kg/d) or saline after a colonic anastomosis. The anastomotic tissue was evaluated on the third, seventh, and 14th postoperative days. Anastomotic bursting pressure, histological parameters, hydroxyproline content, and tissue oxidative stress markers were compared. RESULTS: There was a significant increase in the mean anastomotic bursting pressure in the ghrelin subgroup on the seventh postoperative day (P = 0.035). Histological evaluation demonstrated a significant difference in the neutrophilic infiltrate (P = 0.035) on the third and 14th d and in apoptosis (P = 0.004), granulation tissue (P = 0.011) and peritoneal inflammation (P = 0.014) on the 14th postoperative day. There was a statistically significant increase in the hydroxyproline content in the ghrelin subgroup on the 14th postoperative day (P = 0.043). There were significant differences in the nitrite tissue levels (P = 0.021) on day 3 and in reactive oxygen species (P = 0.012) on day 14. CONCLUSIONS: The administration of ghrelin had beneficial anti-inflammatory and antioxidant effects, increasing the resistance of the anastomosis and the hydroxyproline tissue content in the postoperative period.

Risk of breast implant-associated anaplastic large cell lymphoma in patients submitted to breast implantation: A systematic review.

Although breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a rare disease, its incidence has been increasing. The aim of this study was to assess the risk of BIA-ALCL in women with breast implants. A systematic search was carried out in Pubmed, Scopus, ScienceDirect, LIVIVO, Cochrane Library, Google Scholar, and OpenGrey databases. The risk assessment of bias was based on the Newcastle-Ottawa Scale. The rarity of BIA-ALCL was a major limitation. Although we have found evidence of an increased risk of BIA-ALCL, further studies are needed to understand why some large samples did not present any case of the disease.

Early fragmentation of polyester urethane sheet neither causes persistent oxidative stress nor alters the outcome of normal tissue healing in rat skin.

Silicone breast implant is associated with complications inherent to the surgical procedure. Prosthesis coating with polyurethane, however, commonly reduces the incidence of such complications. In this paper, the authors evaluated the inflammatory histomorphometric profile and oxidative damage associated to the implant of polyester urethane sheets. Forty-eight Wistar rats were divided into Sham or polyester urethane groups (n = 8/group) and underwent a polyester urethane implant in the dorsal skinfold. Tissue samples were collected on days seven, 30, and 90 after surgery and subjected to histomorphometric analysis and biochemical tests. Results were analyzed by one-way ANOVA (p ≤ 0.05). Peri-implant tissue samples exhibited characteristic inflammatory response associated with the biomaterial, with increased vascularization on day seven and augmented levels of IL1-b and TNF-a after 30 days. Peri-implant fibrocystic population was small on day seven, but increased considerably after 90 days. A rise in the carbonyl group levels of skin samples in the polyester urethane group was observed on day seven. Findings suggest that polyester urethane sheets undergo biodegradation at an early stage after implantation, followed by increased vascularity and microencapsulation of biomaterial fragments, without persistent oxidative damage. Fiber arrangement inside the collagen matrix results in a fibrotic scar because of polyester urethane degradation.

Capsular Contracture In Silicone Breast Implants: Insights From Rat Models.

Breast augmentation with silicone implants is one of the most common procedures performed by plastic surgeons around the world. Capsular contracture is a frequent complication in breast augmentation and reconstructive surgery, that requires invasive intervention. The inflammatory response to implanted mammary prostheses appears to be directly associated to capsular contracture. This review discusses the evidences from rat models studies, on the role of inflammation and fibrosis in capsular contraction and its relation to silicone breast implants surface.

[Intestinal microbiota]. / Microbiota intestinal: Estado da arte.

There is accumulative evidence on the multiple functions of the intestinal microflora in relation to the homeostasis of the host. At first considered as a simple mutualism, today this relationship proves to be essential to the health and to pathologic processes, particularly metabolic (eg, obesity) and gastrointestinal (eg, inflammatory bowel disease and functional disorders). The first studies were conducted on the microbiota from fecal material cultured anaerobically. With the advent of molecular biology, it has become possible to determine qualitative and quantitatively the dominant, subdominant and transients species. In recent years, there were advances in the understanding of the relationship betwen the microbiota and the host, as well as among the microorganisms in their respective niches. These advances result from translational integration of microbiology with specialities such as molecular biology, cell phisiology, immunology and ecology. There are few studies on the spatial distribution of the microflora in the gut. Unravelling the topography of the microflora in mammals is a way to validate new animal models for the study of microflora.

Phosphodiesterase 5 as target for adipose tissue disorders.

INTRODUCTION: Adipose tissue as an endocrine organ is responsible for the release of multiple cytokines, which have the most diverse metabolic functions. Therefore, it is extremely important to preserve its physiological health in order to avoid local and systemic disorders. Experiments available in literature show the importance of the nitric oxide (NO)/guanosine 3'5' cyclic monophosphate (cGMP)/protein kinase G (PKG) pathway in adipocyte biology. Phosphodiesterase 5 (PDE5) is an enzyme responsible for cGMP inactivation, and the use of its inhibitors can be an alternative in the search of a more balanced adipose tissue. OBJECTIVE: This review aims to describe the PDE5 role and the possibility of using PDE5 inhibitors in adipocyte physiology derangements and their consequences. DESIGN AND METHODS: Studies published in the last 10years that related PDE5 and its inhibitors to adipose tissue were raised in major databases. RESULTS: PDE5 is present in adipocyte, and PDE5 inhibitors can promote adipogenesis, interfere with adipokines secretion, decrease inflammatory markers expression, and increase the thermogenic potential of white adipose tissue. CONCLUSIONS: PDE5 plays an important role in adipocyte physiology and the use of its inhibitors may prove a useful tool to combat adipose tissue disorders and its highest expression, metabolic syndrome.

Effects of perioperative hypothermia on healing of anastomosis of the colon in rats.

OBJECTIVE: We evaluated the hypothesis that induced perioperative hypothermia in rats causes adverse effects on the healing of colonic anastomosis. MATERIALS AND METHODS: Forty-eight Wistar rats were divided into eight groups of six animals that underwent laparotomy, sigmoid section, and anastomosis. Four groups were operated under normothermic conditions (36 ± 1 °C) and four under hypothermic conditions (32 ± 1 °C). The reoperations were performed on days 3, 7, and 14 post-surgery, and two groups where SHAM reoperated on day 3. We evaluated anastomotic bursting pressure and tissue hydroxyproline content; performed a histological analysis of inflammatory parameters and healing (inflammatory cell infiltrate, edema, fibrin, collagen deposition and apoptotic cells) with categorization scores = 0, 1, 2, 3; and examined the relative quantification gene expression (cDNA) of inflammatory cytokines [interleukin 1 (IL-1), interleukin 6 (IL-6), and interleukin 10 (IL-10)] and growth factors [vascular endothelial growth factor and insulin-like growth factor 1 (IGF-1)] by reverse transcription polymerase chain reaction. RESULTS: Both of the hypothermic groups showed lower anastomotic burst pressure on days 7 and 14 post-surgery, reduced hydroxyproline content on day 14, reduction of inflammatory infiltrates and edema at day 3, and less collagen deposition on day 14. In animals that were hypothermic, the cytokine gene expression showed reduced IL-1 on day 3, reduced IL-6 on days 7 and 14, and reduced IL-10 on days 7 and 14 and a reduction in the growth factor IGF-1 on day 7. CONCLUSION: Perioperative hypothermia had detrimental effects on the healing of colonic anastomosis in rats.

Effects of sildenafil and tadalafil on skin flap viability.

Vascular complication is one of the causes of skin flap healing failure. Sildenafil and tadalafil, a type-5 phosphodiesterase inhibitor, can improve flap viability, however, the action mechanisms involved in this process are still unclear. To assess the effects of orally administered sildenafil and tadalafil on the healing kinetics and skin flap viability, sixty-two Wistar rats were divided into three groups: control (n = 22), sildenafil (n = 20), and tadalafil (n = 20). The solutions were administered orally (dose: 10 mg/kg) immediately after the surgical procedure and then every 24 h. At postoperative days 7 and 14, the skin flap samples were collected, submitted to histological processing and evaluated under optical microscopy. In experimental groups (sildenafil and tadalafil), we found an increased vascularization (p < 0.05) on the 7th and 14th day associated with the ulcer size decrease on the 14th day, although it was not significant. There was a higher influx of neutrophils and a decrease of mononuclear population on the 7th day (p < 0.05). On the 14th day, these differences were observed only in the tadalafil group (p < 0.05). This study suggested positive results with the use of sildenafil and tadalafil as adjuvant drugs in skin flap viability.

Tensile strength study of the abdominal wall following laparotomy synthesis using three types of surgical wires in Wistar rats.

PURPOSE: To study the tensile strength of the abdominal wall following laparotomy synthesis utilizing three types of surgical wires. METHODS: Thirty Wistar rats were randomized into three groups of ten rats each. Each group underwent a 3cm-laparotomy which was closed with 3-0 polyglactin 910, polyglecrapone and catgut wires. After 63 days, euthanasia was performed and part of the abdominal wall was removed with which a strip was produced measuring 2.0 cm in length by 6.0 cm in width comprising the abdominal muscles with the implanted mesh. The sample was fixed in a mechanical test machine in which constant force was applied contrary to the tissue strips. Maximum force was considered, expressed in Newton, until full rupture of the tissue occurred. The non-parametrical Kruskal - Wallis test was used for the statistical analysis, admitting p

Histological study on acute inflammatory reaction to polyurethane-coated silicone implants in rats.

PURPOSE: Evaluating histologically the silicone peri-implant coated by polyurethane inflammation associated to the use of anti-microbial and bacterial contamination. METHODS: It was used 35 Wistar rats. The animals were divided in seven groups: I - Control; II - implant cavity contamination with 10 bacteria/ml; III - implant cavity contamination with 10 bacteria/ml; IV - implant cavity contamination with 10 bacteria/ml; V - identical contamination to group II and implant immersions in anti-microbial solution; VI - identical contamination in group III and implant immersions in the anti-microbial solution; VII - identical contamination of group IV and implant immersions in anti-microbial solution. It was evaluated morphometrically the peri-implant capsules after 30 days of introduction. RESULTS: The factors with more discriminating power were the giants cells of a strange body and the mononuclear. There was no correlation between the bacterial concentrations and the histological alterations. CONCLUSION: 1) The histological standard of the inflammatory reaction around the silicone implant coated with polyurethan is chronic granulomatosis type of a strange body; 2) There isn't correlation between concentration of Staphylococcus epidermidis and histological changes; 3) The use of anti-microbial solution decreased the mononuclear cell reactions, with the increase of giant cells in a strange body.

Sleeve gastrectomy model in Wistar rats.

BACKGROUND: Sleeve gastrectomy (SG) has been used for the surgical treatment of morbid obesity, as a first step or as a definitive treatment. The objective of this pilot study was to establish an animal model for SG in Wistar rats. METHODS: 12 male Wistar rats were operated on. 8 of them underwent a SG, with a hand-sewn invaginating suture, and 4 underwent a laparotomy and stomach manipulation (control group). Sterilized materials, prophylactic antibiotics and nutritional supplementation were used. The animals' weight was checked on the operation day and on a weekly basis, for 7 weeks. RESULTS: The experimental SG model was possible due to careful procedures in the pre- and postoperative period. The average weight loss in the sleeve gastrectomy group was 49.6 g (43 to 60 g) until the 4th week, whereas in the control group average weight loss was 15 g (10 to 25 g) but the weight loss was achieved in the 1st week. After the 7th week, there was weight gain in both groups. However, in the SG group, this gain was significantly lower than in the control group. CONCLUSION: It has been possible to obtain a SG experimental model. The effects of this SG appear to be beneficial in weight loss. Biochemical and molecular mechanisms may also be investigated based on this model.

Experimental study comparing the tensile strength of different surgical meshes following aponeurotic-muscle deformity synthesis on Wistar rats.

PURPOSE: To assess the tensile strength of polypropylene and polypropylene associated with polyglactin meshes (Vypro II--Ethicon, Somerville, NJ, USA) in a situation of partial separation of abdominal muscle aponeurosis on rats. METHODS: Thirty rats were used of the Wistar strain, which were randomized into two groups of 15 specimens each. In both groups an aponeurotic-muscle deformity was created on the abdominal wall measuring 3.0 x 1.0 cm, which was closed with polypropylene mesh (polypropylene group) or Vypro mesh (vypro group). After 28 days the rats underwent euthanasia and an area was removed from the abdominal wall with which a strip was made measuring 2.0 cm in length and 6.0 cm in width comprising the abdominal muscles with the implanted mesh. This sample was placed in a mechanical test machine in which a constant force was applied contrary to the tissue strips. Maximum force expressed in Newton was considered until full rupture of the sample occurred. The non-parametric Kruskal-Wallis test was used for statistical analysis admitting p< 0.05. RESULTS: Out of the thirty animals, there were two deaths in the vypro group and one unit in the polypropylene group was lost. One animal in the polypropylene group developed hernia during the study and another one developed granuloma of the abdominal wall. All animals in both groups developed epiplon adherence to the mesh. The average force was 48.08 N for the polypropylene group and 45.32 for the vypro group. CONCLUSION: In these experimental conditions it could be observed that there is no statistically significant difference in the rupture force of the polypropylene and Vypro meshes (p=0.54).

Effect of post-natal castration on sepsis mortality in rats.

PURPOSE: To investigate the influence of castration in early periods of development on survival to experimental acute sepsis. METHODS: Four groups of 10 (ten) Wistar rats were used. The groups were comprised of males (M), females (F), males castrated on the fourth day of life (CM) and males castrated on the fourth day of life with testosterone replacement (CMR). Sepsis was induced by ligature and cecal perforation in adult life. RESULTS: The analysis of death within 24 hours following sepsis induction showed greater mortality between the M and the CMR groups as compared to the CM and F (p=0.0180) groups. Multiple correspondence analysis (MCA) indicates an association between the M and the CMR groups for death within 24 hours as well as a relationship between the F and the CM groups for the absence of death and death up to 24 hours following sepsis induction. Statistical analysis of the Kaplan-Meier survival curve through log-rank demonstrates a significant difference among the four groups (p=0.0055) and between the M and the F (p=0.0005) groups. CONCLUSION: Data suggest a better survival to sepsis within 24 hours for the F and CM groups, the presence or absence of testosterone in early periods of post-natal life being responsible for these findings.

Histological study of the liver and biochemistry of the blood of Wistar rats following ligature of right hepatic duct.

PURPOSE: To observe the histological alterations in the liver and biochemistry in the blood that can happen in Wistar rat, after the ligature of right hepatic duct. METHODS: In this study were used rats (n=46) of Wistar pedigree. The animal groups (n=46) were distributed in 6 experimented sub-groups (n=6). It was held a ligature surgery of the right hepatic duct and euthanasia in 7, 14, 21, 28, 60 and 90 days and the biochemistry control group (n=10), that animals had 2ml of their blood taken by cardiac puncture for biochemistry study with value analyses of bilirubins, transaminasis, lactic desidrogenasis, alkaline phophatase and gamma-glutamil-transferase. Given the expected time of each group, the animals were submitted to anesthesia procedure and cavity re-opening, being held intra-cardiac puncture and with 2ml blood collected for biochemistry analyses. It was proceeded the liver resection, being the liver put in formol solution to 10% for a period of 24 hours and taken to the histology. RESULTS: It was not possible to identify results that express significant differences as the existence of alterations histological and biochemical between the different groups. CONCLUSION: At the end of the study, it was not possible to identify histological and biochemical alterations that express significant differences between livers of the animals from the right linked hepatic duct and the animals of the control group.

Considerations that may influence the result of trials assessing tensile strength in experimental surgery.

PURPOSE: To provide information gathered upon the execution of trials assessing tensile strength in experimental surgeries. METHODS: Descriptive study considering details on the execution of trials assessing tensile strength in experimental surgery. RESULTS: The analysis of the rupture force in a mechanical test machine is an adequate technique since it provides precise and quick results. It can, undoubtedly, be developed in this context of the eminently mechanical analysis of trials on experimental surgery. CONCLUSION: The utilization of a mechanical test machine is a useful tool in the assessment of materials' strength, providing accurate results. Nevertheless the trials must be well structured analyzing the multiple variables so as to attain a pattern of constant reproducibility and to provide the necessary reliability.

PERITONEAL ADHESIONS TYPE I, III AND TOTAL COLLAGEN ON POLYPROPYLENE AND COATED POLYPROPYLENE MESHES: EXPERIMENTAL STUDY IN RATS.

BACKGROUND: Hernia correction is a routinely performed treatment in surgical practice. The improvement of the operative technique and available materials certainly has been a great benefit to the quality of surgical results. The insertion of prostheses for hernia correction is well-founded in the literature, and has become the standard of treatment when this type of disease is discussed. AIM: To evaluate two available prostheses: the polypropylene and polypropylene coated ones in an experimental model. METHODS: Seven prostheses of each kind were inserted into Wistar rats (Ratus norvegicus albinus) in the anterior abdominal wall of the animal in direct contact with the viscera. After 90 days follow-up were analyzed the intra-abdominal adhesions, and also performed immunohistochemical evaluation and videomorphometry of the total, type I and type III collagen. Histological analysis was also performed with hematoxylin-eosin to evaluate cell types present in each mesh. RESULTS: At 90 days the adhesions were not different among the groups (p=0.335). Total collagen likewise was not statistically different (p=0.810). Statistically there was more type III collagen in the coated polypropylene group (p=0.039) while type I was not different among the prostheses (p=0.050). The lymphocytes were statistically more present in the polypropylene group (p=0.041). CONCLUSION: The coated prosthesis was not different from the polypropylene one regarding the adhesion. Total and type I collagen were not different among the groups, while type III collagen was more present on the coated mesh. There was a greater number of lymphocytes on the polypropylene mesh.

[Expanded polytetrafluoroethylene and polypropylene in the repairing of abdominal wall defects in Wistar rats. Comparative study]. / Uso das telas de politetrafluoroetileno e polipropileno no reparo de defeitos da parede abdominal em ratos Wistar. Estudo comparativo.

PURPOSE: To compare the use of polypropylene and PTFE meshes in the treatment of incisional hernias made experimentally on Wistar rats. METHODS: The experiment used 24 Wistar rats divided into three cohorts: C-A (ressection of a segment of abdominal wall), E-A (ressection and placement of PTFEe mesh), E-B (resection and placement of polypropylene mesh). After 28 days, the mesh and the surrounding tissue were removed and submitted to macroscopic analysis (assessment of the abdominal wall for presence of abscess in the surgical wound and/or skin necrosis, and adhesions) as well as microscopic analysis (presence of fibrosis, necrosis and abscess, counting of macrophages, mononuclears and polymorphonuclears). RESULTS: Adhesions and abscesses in the surgical wound were observed more commonly associated to the group treated with PTFEe. The size of the fibrous tissue was greater in the group treated with polypropylene. Cohort E-A showed PTFEe mesh enveloped by organized fine connective tissue. No groups presented necrosis on the site of the insertion. The highest mononuclear inflammatory reaction occurred in association to PTFEe when compared to the control group, but the findings for the polypropylene mesh were also significant when compared to the control group. In the analysis of the results obtained for cohorts E-A and E-B, a minimal occurrence of polymorphonuclears was noticed in both groups, which indicates low tissue reactivity to both materials used in the present experiment. CONCLUSION: Even with epithelization and proliferation of connective tissue, anchorage between PTFEe and abdominal wall is insufficient, which can result in reherniations.

Morphological analysis of three wound-cleaning processes on potentially contamined wounds in rats.

PURPOSE: To evaluate the inflammatory response of potentially infected wounds treated with isotonic saline solution, chlorhexidine and PVP-I, seven days after surgery. METHODS: Thirty-two male rats were used, divided into 4 groups. All animals had their surgical wounds infected with a standard bacterial inoculum. Control group (A): animals had their surgical wounds sutured without any kind of cleaning. Saline solution group (B): animals had their wounds cleaned with saline solution. Chlorhexidine group (C): animals had their wounds cleaned with chlorhexidine. PVP-I group (D): animals had their wounds cleaned with PVP-I. Seven days after surgery, all the animals had their skin submitted to microscopic and macroscopic evaluation. RESULTS: Edema was found on all histological slices analyzed, as well as vascular proliferation and congestion. Groups A and D showed presence of mild neutrophilic infiltrate, and moderate lymphocytic and macrophage infiltrate. Group B showed severe neutrophilic, macrophage, and lymphocytic infiltrate. Group C showed moderate neutrophilic, macrophage, and lymphocytic infiltrate. CONCLUSION: Group D was the group which showed inflammatory infiltrate most similar to the group that was not submitted to treatment.

[Rats resistance to fecal peritonitis when subjected to total splenectomy and auto-implant of the spleen in the retroperitoneum]. / Resistência de ratos à peritonite fecal quando submetidos a esplenectomia e auto-implante do baço no retroperitônio.

PURPOSE: This study was developed to evaluated the effects of spleen transplants in the protection against abdominal sepsis in young and old Wistar rats. METHODS: Fifty-four young and old Wistar rats were utilized (90 and 180 days respectively) being distributed in three groups as follows: Sham Group, where the animal were submitted to laparotomy with manipulation of only intestine (n=12 young and adult animals), Splenectomy Group, in which the animals were subjected to total splenectomy (n=20 young and adult animals) and an Auto-implant Group, where the animals were subjected to total splenectomy and a third of the spleen was implanted in a bag in the retroperitoneum (n=22 young and adult animals). After three months the animals were subjected to a new laparotomy with binding and caecum perforation to stimulate abdominal sepsis and were accompanied until the moment of death to establish a mortality curve. RESULTS: There was recuperation of the spleen implanted in all animals. There was no significant difference in the time of death among the groups. The young animals apparently had a better response, however it was not statistically significant. CONCLUSION: This study demonstrated that spleen implant in the retroperitoneum do not prove to be an effective protection against abdominal sepsis in comparison with the splenectomized rats.

[Ileocecal valve reconstruction in dogs]. / Reconstituição da válvula ileocecal em cães.

PURPOSE: The importance of keeping the ileocecal valve in the intestinal ressections has been reported by several authors. When preserved, the ileocecal valve was related to a longer survival and prevention of the short bowel syndrome, due to its ability to block the colonic content reflux into the ileum and to avoid the rapid empting of the ileal content into the cecum. It was assessed a tecnique of ileocecal valve reconstitution, based on vesicoureteral anti-reflux tecniques. METHODS: Fourteen beagles were operated. Seven underwent ileocecal valve reconstitution following the tecnique proposed and in the other seven a simple end-to-end anastomosis was performed. To assess the new valve, it was done the clinical follow up, the microbiologic analysis and the manometric study. RESULTS: Clinically, during 45 days of follow up, there was no difference between the dogs with and without ileocecal reconstitution. In the aerobic bacteria analysis, the predominant bacterium was Escherichia coli. Quantitatively, the cultures grew in an irregular way, so that it was not able to compare the bacterial growth between the groups with or without ileocecal valve. The new valve had a colo-ileal reflux pressure similar to that of the physiological valve (P > 0.05). However, when compared to the non valve group, the reflux pressures of the physiological valve and new valve were significantly higher, with P < 0.05 and P < 0.001, respectively. CONCLUSION: In this study, the reconstituted ileocecal valve served as a barrier to the colo-ileal reflux just as the physiological valve does.