Anti-Inflammatory Activity of Fucan from Spatoglossum schröederi in a Murine Model of Generalized Inflammation Induced by Zymosan.

Fucans from marine algae have been the object of many studies that demonstrated a broad spectrum of biological activities, including anti-inflammatory effects. The aim of this study was to verify the protective effects of a fucan extracted from the brown algae Spatoglossum schröederi in animals submitted to a generalized inflammation model induced by zymosan (ZIGI). BALB/c mice were first submitted to zymosan-induced peritonitis to evaluate the treatment dose capable of inhibiting the induced cellular migration in a simple model of inflammation. Mice were treated by the intravenous route with three doses (20, 10, and 5 mg/kg) of our fucan and, 1 h later, were inoculated with an intraperitoneal dose of zymosan (40 mg/kg). Peritoneal exudate was collected 24 h later for the evaluation of leukocyte migration. Doses of the fucan of Spatoglossum schröederi at 20 and 10 mg/kg reduced peritoneal cellular migration and were selected to perform ZIGI experiments. In the ZIGI model, treatment was administered 1 h before and 6 h after the zymosan inoculation (500 mg/kg). Treatments and challenges were administered via intravenous and intraperitoneal routes, respectively. Systemic toxicity was assessed 6 h after inoculation, based on three clinical signs (bristly hair, prostration, and diarrhea). The peritoneal exudate was collected to assess cellular migration and IL-6 levels, while blood samples were collected to determine IL-6, ALT, and AST levels. Liver tissue was collected for histopathological analysis. In another experimental series, weight loss was evaluated for 15 days after zymosan inoculation and fucan treatment. The fucan treatment did not present any effect on ZIGI systemic toxicity; however, a fucan dose of 20 mg/kg was capable of reducing the weight loss in treated mice. The treatment with both doses also reduced the cellular migration and reduced IL-6 levels in peritoneal exudate and serum in doses of 20 and 10 mg/kg, respectively. They also presented a protective effect in the liver, with a reduction in hepatic transaminase levels in both doses of treatment and attenuated histological damage in the liver at a dose of 10 mg/kg. Fucan from S. schröederi presented a promising pharmacological activity upon the murine model of ZIGI, with potential anti-inflammatory and hepatic protective effects, and should be the target of profound and elucidative studies.

Effects of Terbufos (Organophosphate) on Larval Behaviour of Two Forensically Important Diptera Species: Contributions for Entomotoxicology.

Neurotoxicant compounds interfere with the behaviour and biology of insects, significantly altering their locomotion patterns. However, little is known about the effect of organophosphates, neurotoxicants for agricultural, domestic and industrial use, on the larval movement of necrophagous flies, although being responsible for frequent cases of poisoning and accidental or intentional deaths. Thus, we aimed to study the influence of Terbufos (organophosphate) on the activity and mobility patterns of Lucilia eximia (Wiedemann 1819) (Calliphoridae) and Peckia (Peckia) chrysostoma (Wiedemann 1830) (Sarcophagidae) immatures collected from rat carcasses intoxicated with 5, 10 or 20 mg/kg of Terbufos, to evaluate (i) peristaltic movements and body contractions, and (ii) distance and shape of the trajectory travelled by the larva. Behavioural parameters were analysed in loco and through videos. We observed that the presence of Terbufos altered poisoned larvae's activity and body mobility in both taxon and dose-dependent manner. Lucilia eximia larvae were more active, with greater frequency of body movements and lateral contractions when intoxicated with high and intermediate doses of Terbufos. On the other hand, P. (P.) chrysostoma immatures were less active, with fewer body and lateral contractions when intoxicated with the high dose of the compound. This work experimentally demonstrates that the presence of Terbufos can alters the mobility and movement of intoxicated necrophagous Diptera, essential components of the cadaveric fauna.

Behavioural Aspects of the Prey-Predator Interaction Among Necrophagous Diptera: Implications for Cadaveric Colonization.

Predation is a major process in determining the composition and dynamics of necrophagous dipteran assemblages and has implications for the colonization of cadavers. This work describes behavioural interactions between necrophagous larvae under a predator-prey perspective, using as a model the predatory species Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae) and three species of prey: Lucilia eximia (Wiedemann) (Calliphoridae), Synthesiomyia nudiseta (Wulp) (Muscidae) and Peckia (Peckia) chrysostoma (Wiedemann) (Sarcophagidae). Using experimental arenas, we observed behavioural acts, such as escape, avoidance and prey discrimination in three experiments, which also incorporated predator density. We demonstrate that the number of escapes, avoidance and predation varies according to the type of prey. Lucilia eximia and P. chrysostoma are able to avoid and/or escape the predator more frequently when compared to S. nudiseta. At least 70% of larvae of both species successfully evaded from C. albiceps attack. Low frequency of escape, associated with strong ability to counterattack, was observed for S. nudiseta. Peckia chrysostoma and L. eximia were the preferred items in the experiment of prey discrimination in both 2- and 3-choice tests. Predation occurs quickly, and the minimum predation time varied according to the prey species and predator density. Remarkably, prey handling varied with the species: whilst individual larvae chased and killed L. eximia, 75% of predation of P. chrysostoma occurred in groups of two or more C. albiceps larvae. Differential intraguild predation has implications for reducing populations of carrion insects-consequently affecting the likelihood of sampling necrophagous larvae in human cadavers.

Carrion decomposition and assemblage of necrophagous dipterans associated with Terbufos (Organophosphate) intoxicated rat carcasses.

Organophosphate use represents one of the main causes of intentional and accidental poisoning in Brazil. Because they induce alteration in carcass decomposition and succession of necrophagous Diptera, they are important investigative tool in forensic entomology for determining the postmortem interval (PMI) and cause of death. Thus, this work aimed to evaluate the influence of Terbufos, the most commonly used organophosphate for suicides in Rio Grande do Norte, Brazil, in the decomposition process and necrophagous fly assemblies in intoxicated rat carcasses. For this, 150g female Wistar rats received, by gavage, 200µL of Terbufos (5mg/kg or 10mg/kg) or distilled water (control). Approximately 30 minutes after administration, animals were euthanized and distributed in suspended traps to decompose under environmental conditions. Decomposition was monitored daily, with photographic record and collection of the visiting dipterofauna until the dry phase. Data show that the higher dose of Terbufos i) accelerates carcass decomposition in 24h; ii) decreases the species richness and abundance of scavengers flies when compared to the control; iii) changes the succession pattern, delaying the arrival of important species for the PMI estimate and iv) causes 8% mortality of the visiting dipterofauna. This work provides relevant information about dipteran assemblages and changes in the cadaver decomposition process associated with Terbufos intoxication, which may assist in future investigative processes with suspected organophosphate poisoning.