Comparative studies by cell culture and in vivo implantation test on the toxicity of natural rubber latex materials

Abstract

Colony assay using V79 cells, the agar diffusion assay with L929 cells, and the 7-day rabbit muscle implantation test were employed to evaluate the cytotoxicity and tissue toxicity of natural rubber latex (NRL) materials. The in vivo implantation test showed that, among 13 histological parameters, thickness of inflammatory layer was the most useful index to evaluate tissue responses quantitatively. A comparison of the in vivo and in vitro parameters revealed the following correlations between the thickness of the inflammatory layer and cytotoxicity indices: Colony assay of the extracts, IC50: r = 0.80; Agar diffusion assay, Zone index: r = 0.73; Lysis index: r = 0.61. From these results, it appears that the colony assay provides a more reliable prediction of the tissue response than the agar diffusion assay.

Biocompatibility of Pegylated Fibrinogen and Its Effect on Healing of Full-Thickness Skin Defects: A Preliminary Study in Rats

“…The H&E stained sections were semi-quantitatively evaluated with a microscope (Leica MDL 505097, Leica Instruments GmbH, Nussloch, Germany) using a modified score [44,45] given in Table 1. The presence of immune cells (granulocytes, macrophages, lymphocytes, FBGCs) and material remnants was recorded as the mean of two non-overlapping high power optical fields (HPF) per section (20x magnification).…”

Improved Biocompatibility of Titanium–Zirconium (Ti–Zr) Alloy: Tissue Reaction and Sensitization to Ti–Zr Alloy Compared with Pure Ti and Zr in Rat Implantation Study

“…All animals were cared for according to the Japan animal rights act and the NIHS-Japan guidelines for the care and use of laboratory animals. 26,29) The animals were anesthetized with 50 mg/kg Nembutal (sodium pentobarbital, Dainabot Co., Ltd., Osaka, Japan) via intraperitoneal injection. After the induction of anesthesia, the hair on the back was shaved around the implantation site and the skin was sterilized by brushing with a 70% ethanol solution.…”

“…The histological sections were examined microscopically, and the tissue responses-i.e., the distributions of fibroblasts, neutrophils, eosinophils, macrophages, giant cells, lymphocytes, and plasma cells-in the fibrous capsule that formed around the specimen were recorded, as was the infiltration of inflammatory cells around the capsule. 26,29) The intensity of these histological items was ranked as À = no frequency (0), þ = low frequency (1), þþ = moderate frequency (2) and þþþ = high frequency (3). The total score for the eight items was derived.…”

“…The thickness of the fibrous capsule that formed around the specimen was also measured by a micrometer. 29) The thickness was determined in the orthogonal direction of the boundary between the capsule and the hole left by the specimen, and expressed as a mean value of 10 spots.…”

Studies on gamma irradiated rubber materials

“…They are used in manufacturing of seal gaskets, vibration cushioning, protection equipment, medical devices, etc. [1], [2]. Beside the constant effort of recycling used materials, it seems more appropriate to manufacture and use biodegradable and renewable row materials.…”