Comparative study of two vitreous humor sampling methods in rabbits

Abstract

To compare and evaluate two methodologies, entire-sampling and micro-sampling for the harvesting of vitreous humor, the vitreous humor of rabbits were sampled with the two methods respectively, and the concentrations of calcium, chlorine, potassium, sodium and phosphorus of the were measured. The results showed that the differences in the variance coefficient and two-eye concentrations of micro-sampled specimens were less than those of the entire-sampled specimens. In the micro-sampling group, the concentrations of repeated micro-sampling showed no differences among different groups (P > 0.05) and the intra-ocular fluid dynamics did not have significant influence on post-mortem sampling. The sampling technique may affect the concentrations of specimen collected. Our study suggests that micro-sampling is less influenced by the human factor and is reliable, reproducible, and more suitable for forensic investigation.

Vitreous humor analysis for the detection of xenobiotics in forensic toxicology: a review

“…The volume withdrawn may be replaced by water or physiological saline in order to maintain the aspect of the eyeball [ 80 ]. Total versus micro-aliquot (50 µL) sampling procedures were compared in a rabbit model [ 81 ]. Micro-sampling seemed more reproducible for ion assay (calcium, chloride, potassium, sodium and phosphorus), but is too limited at present for forensic toxicology investigation.…”

“…Electrolyte and glucose samples have been reported to be lateralization-sensitive [ 82 – 85 ]. Rather than reflecting differential concentration between the two eyeballs, this may be a question of reproducibility related to the sampling procedure [ 81 ], of analytical problems due to the gelatinous consistency of VH [ 86 ], and of hematic contamination [ 87 ]. Bévalot et al [ 88 ], in a series of 92 human autopsies, found the left/right VH differential to be non-significant for meprobamate.…”

A Study on the Estimation of Postmortem Interval Based on Environmental Temperature and Concentrations of Substance in Vitreous Humor

“…Moreover, due to the large sample size required by previous biochemical measurement techniques and low detection sensitivities, an entire‐sampling method in which all the VH was harvested was adopted by early studies, and therefore each eye could only be sampled once. In recent years, Wang et al used a micro‐sampling method in both eyes to confirm that no significant differences were observed in the contents of VH potassium, sodium, calcium, chlorine, phosphorus, and other molecules between the entire‐sampling and micro‐sampling methods, confirming the feasibility of micro‐sampling. Liu et al used the double‐eye alternating micro‐sampling method to measure the patterns of change in VH K + and other ion concentrations in rabbits after death and established an equation to estimate PMI at a single temperature.…”

“…The double‐eye alternating micro‐sampling method reported by Wang et al was adopted, and 80–100 μL of VH sample was collected from the left eye of each rabbit at 0, 24, 48, 72, 96, and 120 h after death. Similar samples were collected from the right eyes at 12, 36, 60, 84, and 108 h after death.…”

“…The homogeneity of VH ion concentrations has never been determined (6,7). Moreover, due to the large sample size required by previous biochemical measurement techniques and low detection sensitivities, an entire-sampling method in which all the VH was harvested was adopted by early studies, and therefore each eye could only be sampled once.…”