A Protocol to Perform Systemic Lipopolysacharide (LPS) Challenge in Rats / Protocolo para realizar reto sistémico con lipopolisacárido (LPS) en ratas

Abstract 19. Lipopolysaccharide (LPS) is a component of the outer membrane of Gram-negative bacteria. In animals, intraperitoneal administration of LPS, stimulates innate immunity and the production of proinflammatory cytokines. LPS provides an inflammatory stimulus that activates the neuroimmune and neuroendocrine systems resulting in a set of responses termed sickness behavior. The purpose of this protocol is to describe step-by-step the preparation and procedure of application of intraperitoneal injection of LPS in rats, as a guide for those researchers that want to use this assay to mount an inflammatory response. LPS intraperitoneal challenge in rats has been widely used to evaluate antiinflammatory reagents and to address basic scientific questions.

Resumen 23. El lipopolisacárido (LPS) es un componente de la membrana externa de las bacterias Gram negativas. En animales, la administración intraperitoneal de LPS estimula la inmunidad innata y la producción de citoquinas proinflamatorias. El LPS proporciona un estímulo inflamatorio que activa el sistema neuroinmunológico y el sistema neuroendocrino, lo que da como resultado un conjunto de respuestas denominadas conductas de enfermedad. El propósito de este protocolo es describir paso a paso la preparación y el procedimiento de aplicación de la inyección intraperitoneal de LPS en ratas, como una guía para aquellos investigadores que desean utilizar este método para estimular una respuesta inflamatoria en el animal. La estimulación con LPS en ratas, aplicada intraperitonealmente, se ha utilizado ampliamente para evaluar reactivos antiinflamatorios y para abordar preguntas básicas de investigación científica.

Ultrasound-guided intraperitoneal cisplatin after the maximum cytoreductive surgery of pseudomyxoma peritonei

In the past, pseudomyxoma peritonei was considered an incurable disease and often no active treatment was given. With the advent of cyto-reductive surgery, including peritonectomy procedures and intra peritoneal chemotherapy, long-term survival of these patients became actually possible. To study the impact of the intraperitoneal hyperthermic chemotherapy [cisplatin], when locally administered in patients who presented with pseudomyxoma peritonei and were treated by extensive cyto-reductive surgery. Nine patients with and. peritoneal adenomucinosis or carcinomatosis arising from the appendix who presented with a clinical picture of pseudomyxoma peritonei were diagnosed, and treated by cyto-reductive surgery followed by 6 cycles of ultrasound-guided intraperitoneal hyperthermic cisplatin. Following aggressive surgical approach and intraperitoneal chemotherapy, 7 patients had 1 year disease free survival, achieved independent activity in daily living and had an improved quality of life. The other 2 patients developed recurrences at 8 and 10 months following the completion of treatment. No major [grade III] texicities were observed. Pseudomyxoma peritonei is a treatable condition that may result in long-term disease free survival. Successful management can be achieved by combining cyto-reductive surgery and intraperitoneal hyperthermic chemotherapy

Effect of centrally and peripherally administered obestatin on food and water intake in rats

This work was designed to study the effects of acute obestatin administration on food and water intake, as well as on body weight in rats. In addition, the effect of blocking the efferent cholinergic vagal fibers on food intake was also tested in search for a possible mechanism of action. The study was carried out on 48 adult male rats with weight ranging from [185-200] grams and was divided into 3 sections. Section A intracerebroventricular [ICV] injection: consisted of 24 rats that were divided into 4 groups [6 / group]. Rats in group 1 served as control and were injected with ICV saline. Rats in groups 2, 3, 4 were injected ICV obestatin in doses 15, 25, 50 nM/kg, respectively. Section B intraperitoneal injection: Which included 24 rats divided into 4 groups [6 / group]. Rats in group 1 were injected with IP saline [control group]. Obestatin was injected by IP route in the other groups: 2, 3, 4 in doses of 50, 100, 1000 nM/ kg, respectively. Cumulative water and food intake were monitored at 1, 3, 6 and 24 hours after both ICV and IP obestatin injection and were expressed per rat. Plasma osmolality was measured at 3 and 6 hours after ICV and IP obestatin injection. The differences in body weight of rats were recorded at the end of 24 hours. Section C: rats in the 2 groups injected with the highest doses of obestatin [50 nM/kg ICV and 1000 nM/kg IP] were selected the following day and pretreated with atropine sulphate IP in a dose of 500 ug/kg.15 minutes before they were reinjected with obestatin in the same doses used in the previous day. Food and water intake were assessed after 3 hours of injection. ICV and IF injection of obestatin revealed a significantly lower water intake versus the control that appeared at 3 hours after ICV [15 nM/kg obestatin] and also at 3 hours after IP [100 nM/kg obestatin]. With higher doses of obestatin injection [ICV 25 and 50 nM/kg and IP 1000 nM/kg] the inhibition of water intake showed a significant dose dependant effect at 1 and 3 hours. Plasma osmolality showed no significant difference when compared between the studied groups after both ICV and IP obestatin injections at 3 and 6 hours. The inhibition of food intake occurred only at 3 hours with the highest doses of obestatin injected [ICV 50 nM/kg and P 1000 nM/kg] compared with the control group. No significant differences were detected in water and food intakes and also in body weight differences after 24 hours compared with the control after obestatin injection by either ICV or P routes. As regards testing the possible involvement of vagal efferent cholinergic mechanism in obestatin's action, the groups injected with the highest doses of obestatin [50 nM/kg ICV and 1000 nM/kg IP] 15 minutes after atropine premedication as well as the non pretreated groups showed a significant decrease of water and food intake at 3 hours compared with the control group. Furthermore, there were no statistically significant differences between atropine pretreated and non pretreated groups injected by the highest obestatin doses as regards food and water intake. Obestatin primarily has an effect to inhibit thirst after acute administration probably by an effect on one of the circumventricular organs. It has a weaker effect on food intake. may be because it has to diffuse to food regulating centers in the brain or because the food intake is regulated by several peptides that may antagonize each other. The vagus efferent cholinergic mechanism has no role in the inhibitory effect of obestatin on food intake. Obestatin should gain more attention as a peptide regulating water balance rather than food intake and its effect on angiotensin II and vasopressin should be investigated

Animal model of the abdominal compartment syndrome as a single insult and as a second insult in rats

The objective of this paper was to develop a clinically relevant abdominal compartment syndrome experimental model, as a single insult and as a second insult flowing hemorrhagic shock. In the single insult model, Sprague-Dawley male-rats are anesthetized, invasively monitored (central venous pressure and mean arterial pressure), and mechanically ventilated during intraperitoneal injection of air to provoke the abdominal compartment syndrome (25 mmHg) for 60 minutes. In the two insult model, Sprague-Dawley male-rats are anesthetized, invasively monitored (mean arterial pressure) and bled to a mean arterial pressure of 30 mmHg for 45 minutes. Fluid resuscitation is accomplished by infusing 0.9 percent sodium chloride solution (0.9 percent NaCl) 33.2 ml/kg plus 75 percent of shed blood volume. During this phase a laparotomy is performed. Two hours after the beginning of the hemorrhagic shock phase the animals are anesthetized, intubated (orotracheal), mechanically ventilated (mean arterial pressure), and the intra-abdominal pressure is increased to 25 mmHg for 60 minutes, as a second insult. A 0.9 percent NaCl solution is infused during this phase (45 ml/kg/h). Hemorrhagic shock and the abdominal compartment syndrome behave as clinically relevant additive insults.