Honey as Fixative and Safer Substitute for Formalin in Histology

Abstract

Formalin is a popular fixative and biohazard in histology and pathology laboratories. The objectives were to investigate the physiochemical properties and effect of different concentrations of honey as fixative on gross morphology and histology of tissues. Honey's glucose concentration and pH were measured. Five organs from goat were gotten in pairs and small tissues cut before being grouped into A and B. Group A were fixed in 20%, 50%, 70%, 90%,100% honey concentrations while group B were fixed in 10% buffered formal saline for 48 hours-6 months. The cut tissues were processed by paraffin wax-embedding method and stained with haematoxylin and eosin. Glucose concentration was 284mmol/l and pH was 4.0. Macroscopically, tissues fixed in 20% and 50% honey showed putrefaction changes after 72 hours and were statistically significant (p=0.004). Tissues preserved in 70%, 90% and 100% honey were properly fixed for up to 6 months and beyond. Minor differences in nuclear and cytoplasmic staining (p=0.391), intensity and clarity of histological details (p=0.252) among the honey-fixed group were not statistically significant. In conclusion, the 70-100% honeys are suitable for long term gross preservation while 20-50% concentrations give excellent tissue staining characteristics. Thus, honey is a safer substitute for formalin.