Raman spectroscopy of DNA packaging in individual human sperm cells distinguishes normal from abnormal cells

Abstract

Healthy human males produce sperm cells of which about 25–40% have abnormal head shapes. Increases in the percentage of sperm exhibiting aberrant sperm head morphologies have been correlated with male infertility, and biochemical studies of pooled sperm have suggested that sperm with abnormal shape may contain DNA that has not been properly repackaged by protamine during spermatid development. We have used micro‐Raman spectroscopy to obtain Raman spectra from individual human sperm cells and examined how differences in the Raman spectra of sperm chromatin correlate with cell shape. We show that Raman spectra of individual sperm cells contain vibrational marker modes that can be used to assess the efficiency of DNA‐packaging for each cell. Raman spectra obtained from sperm cells with normal shape provide evidence that DNA in these sperm is very efficiently packaged. We find, however, that the relative protein content per cell and DNA packaging efficiencies are distributed over a relatively wide range for sperm cells with both normal and abnormal shape. These findings indicate that single cell Raman spectroscopy should be a valuable tool in assessing the quality of sperm cells for in‐vitro fertilization. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Evaluation of the potential of Raman microspectroscopy for prediction of chemotherapeutic response to cisplatin in lung adenocarcinoma

“…It is therefore of interest to understand details of the molecular and biochemical 35 mechanisms associated with the biological activity of existing commercial anti-cancer agents. The potential of confocal Raman microspectroscopy (CRM) for the analysis of biological tissue 1 and the effect of external agents on the cell [2][3][4][5][6] has been demonstrated. CRM is non- 40 invasive, cost effective, rapid and requires no sample labelling prior to analysis 7 .…”

A novel sorting technology allows for highly efficient selection of sperm without chromatin damage

“…Existing means of evaluating sperm in a non-consumptive manner include the utilization of cumulus cells and zonae pellucida of immature oocytes to improve selection of optimal sperm [Black et al 2010;Franken and Bastiaan 2009;Paes Almeida Ferreira de Braga et al 2009]. Other studies have considered the use of Raman microspectrometry; however, the technique has not been thoroughly evaluated in assessing if it improves IVF outcomes [Huser et al 2009]. It is possible that the future will encompass multistep non-consumptive sperm selection to achieve optimal outcomes based on initial evaluation of the infertile couple [Henkel 2012].…”

The role of epigenetics in spermatogenesis

“…[48,55,56] Besides variations were detected in average P1/P2 ratio in ejaculate at different measurement time points. [57,58] In conclusion, abnormal protamination is seen prevalently in men with abnormal sperm parameters contrary to fertile men with normal sperm parameters. [53,59] In many studies abnormal replacement of histones by protamines have been associated with reduced semen quality, decreased success rates of IVF, and pregnancy rates.…”