Repeated collection of cerebrospinal fluid from the lumbosacral region of ewes
Quintela, Homero GuillhermoBielli, AlejandroTorterolo, PabloLagos, PatriciaAlzugaray, StefaníaUngerfeld, Rodolfo
Background: Cerebrospinal fluid is a vital fluid from the central nervous system. Since CSF contains proteins, enzymes, hormones, neuropeptides and neurotransmitters that play critical regulatory roles in many different physiological processes, it has been extensively studied to explore different nervous disorders. Since CSF is a vital fluid from the CNS, used for clinical examination of the CNS in ruminants and other domestic species. CSF may be collected in ewes under field conditions, which allows the diagnosis of bacterial and metabolic diseases, as well as using it for cytological studies and biochemical analysis. Depending on the study, in opportunity the sampling protocol should be repeated to measure dynamic changes in the parameters selected for the analysis. Under field conditions, obtaining CSF samples from ewes is a difficult task. Thus, the aim of this work was to determine if it is possible to obtain repeated extractions of CSF by lumbosacral puncture from the same ewes under fi eld conditions. Materials, Methods & Results: The CSF was sampled in three successive weekly collections from nine ewes sedated with ketamine. The procedure collections were made by the same trained operator, who stood behind the ewe, facing its back. Having checked that the sagital plane of the animal was perpendicular to the horizontal plane the puncture point was found by manual palpation at the slight depression between the ends of the spinous apophyses of the last lumbar and first sacral vertebrae. The wool was separated, and the area was cleansed with iodine solution. The puncture was performed with a spinal needle, after it had penetrated through the skin, the needle was pushed forward very slowly. When was listening for any vibrations ('clicks'), suggesting that the needle had crossed the dural membrane and entered into the arachnoidal space. Then, the syringe needle was withdrawn and the CSF came out slowly, either immediately or after some slow movements of the needle. If CSF did not come out, the puncture was deepened further on until the ventral arachnoidal space was reached. In the first and second collection, limpid CSF samples were obtained in all (9/9, 100%) and in 8/9 animals (89%), respectively. However, limpid CSF samples were obtained only in 4 of the animals one week later (4/9, 44 % P = 0.01). The volume of CSF extracted ranged from 0.6 to 0.9 mL/sample/animal. Discussion: The sequential collection of CSF in ewes is possible under field conditions to obtain a high percentage of samples to the along of three weekly extraction events. When only the first extraction event was considered, the sampling was totally effective even entirety of the animals. Yet by the third sampling, we obtained fewer samples than in the second event. In the present technique of repeated puncture was yielded a high efficacy in the first collection at random chosen ewes. The decrease in effectiveness was probably due to cumulative tissue damage and formation of extensive fibrous adhesions in the subarachnoidal space, which would compromise partially or totally the flow of CSF. The volume of CSF collected by ewe along the three repeated extractions did not vary, although it tended to decrease as repeated collections were performed. This tendency could also be linked with cumulative tissue damage. Nevertheless, our range of volume of CSF obtained for ewe is similar to volumes obtained in similar report. We concluded that the efficiency of weekly CSF extraction in ewes managed under field conditions decreases in the third sampling occasion.
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