Toxicidade do cloridrato de tramadol e da cicuta douglasii no sistema nervoso central em modelos experimentais
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| Hlavní autor: | |
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| Datum vydání: | 2015 |
| Médium: | Doctoral thesis |
| Jazyk: | por |
| Zdroj: | Repositório Institucional da UFG |
| Download full: | http://repositorio.bc.ufg.br/tede/handle/tede/5697 |
Shrnutí: | This thesis presents two different studies about neurotoxicity in laboratory animals. The first study was about a sintetic analgesic called tramadol hydrochloride. The second study is about an natural poison plant called Cicuta douglasii. Tramadol is considered a safe drug as compared to other opioids. However, it has been suggested that spinal administration may trigger neurotoxicity. The objective of this study was to evaluate the neurotoxic effects of tramadol administered by spinal injection in rabbits. Thirty-two rabbits were randomly divided into two groups of 16 animals, with a control group (CG) and a tramadol group (TG). Each group was divided into four subgroups according to the application site (epidural and intrathecal) and evaluation time (seven and 30 days). For administration of tramadol or saline into the epidural or intrathecal space, a polyethylene catheter was implanted between the sixth and seventh lumbar spinous process where it remained for seven consecutive days in all animals. Various clinical and histology evaluations were conducted including determining the treatment effects on the frequency and severity of vacuolization, gliosis, inflammatory infiltrate, heart attacks, bleeding, chromatolysis, cellular edema, Wallerian degeneration, and malacia. Significant differences were found between groups for the Wallerian degeneration. Wallerian degeneration was more frequent in TG than in the CG. We conclude that tramadol can worsen nerve fiber lesions, as shown by Wallerian degeneration caused by catheterization of the epidural and intrathecal space in rabbits. Water hemlock are plants of the genus Cicuta and are toxic to animals and humans. The primary toxin is, cicutoxin, which is present in large concentrations in the tubers; other parts of the plant are toxic, but may contain lower concentrations of cicutoxin. Further, other forms of cicutoxin such as cicutols may contribute to toxicity in various plant parts. The objective of this study was to determine the toxicity of different parts of Cicuta douglasii and characterize their behavioral effects in mice. An aqueous extract was made of green seeds, dry seeds, tubers, flowers and stems of Cicuta douglasii and dosed orally to mice to determine the LD50 (the up and down test). The results indicated that only the green seeds and tubers were toxic to animals by inducing clonic-tonic seizures and death. The LD50 was 17mg/kg and 1320mg/kg for tubers and green seed, respectively. Several tests were used to evaluate motor function and behavior in treated vs. control mice including Grip Strength, Rotarod, Tremor Monitor and Open Field. For each test 12 animals were used per group. The control group (CG) received saline orally, one group received 40% of the LD50 orally (G40) and another group received 85% of the LD50 (G85). The animals were evaluated before gavage and 30 min, 90 min, 120 min, 150 min, 180 min, 240 min and 300 min after gavage. In summary, Cicuta douglasii affected muscle function of mice, including their ability to grasp and hold onto objects, their balance and motility on a Rotarod, motor activity, and exploratory and anxiety-related (i.e., thigmotaxis) behaviors. Seizures interspersed with CNS depression were observed in animals poisoned by Cicuta douglasii. |