A. Mantuano

Effects of soft X-ray radiation damage on paraffin-embedded rat tissues supported on ultralene: a chemical perspective

Radiation damage is an important aspect to be considered when analysing biological samples with X-ray techniques as it can induce chemical and structural changes in the specimens. This work aims to provide new insights into the soft X-ray induced radiation damage of the complete sample, including not only the biological tissue itself but also the substrate and embedding medium, and the tissue fixation procedure. Sample preparation and handling involves an unavoidable interaction with the sample matrix and could play an important role in the radiation-damage mechanism. To understand the influence of sample preparation and handling on radiation damage, the effects of soft X-ray exposure at different doses on ultralene, paraffin and on paraffin-embedded rat tissues were studied using Fourier-transform infrared (FTIR) microspectroscopy and X-ray microscopy. Tissues were preserved with three different commonly used fixatives: formalin, glutaraldehyde and Karnovsky. FTIR results showed that ultralene and paraffin undergo a dose-dependent degradation of their vibrational profiles, consistent with radiation-induced oxidative damage. In addition, formalin fixative has been shown to improve the preservation of the secondary structure of proteins in tissues compared with both glutaraldehyde and Karnovsky fixation. However, conclusive considerations cannot be drawn on the optimal fixation protocol because of the interference introduced by both substrate and embedding medium in the spectral regions specific to tissue lipids, nucleic acids and carbohydrates. Notably, despite the detected alterations affecting the chemical architecture of the sample as a whole, composed of tissue, substrate and embedding medium, the structural morphology of the tissues at the micrometre scale is essentially preserved even at the highest exposure dose.

Synchrotron microtomography to evaluate effects of different polychemotherapy drugs on cortical bone structure

Abstract Purpose: To determine the effects of different polychemotherapy drugs on cortical bone structure, the femur diaphysis of rats were treated with two different chemotherapy drugs, AC (doxorubicin + cyclophosphamide) and TC (docetaxel + cyclophosphamide), and evaluated by 3D morphological analysis using synchrotron radiation microtomography. Materials and methods: Wistar rats were classified into three groups. One group received doses of docetaxel and cyclophosphamide (G1) – TC regimen; a second group received doses of doxorubicin and cyclophosphamide (G2) – AC regimen; while a control group (G0) received no further treatment. 3D tomographic images of the rats’ femurs were obtained at the SYRMEP (Synchrotron Radiation for Medical Physics) beamline at the ELETTRA Synchrotron Laboratory in Trieste, Italy, using monochromatic X-rays with resolution of 9 μm. Results: It could be shown that the treatment caused significant differences in morphological parameters measured from the 3D images of femur diaphysis of rats, among the studied groups, complementing a previous study using stereological methods, biochemistry and electron microscopy. Conclusions: Our results indicate that the same process of osteoporosis caused by advancing age might occur in young women treated with docetaxel + cyclophosphamide (TC) and doxorubicin + cyclophosphamide (AC). 3D microtomography was shown to be an outstanding technique for bone analysis.