Histomorphological Comparison of Tissues Fixed in Conventional Formalin and Eco-friendly Jaggery Solution: A Cross-sectional Study

Abstract

Introduction: Tissue fixation is an essential step in the microscopic preparation of tissues to preserve them by preventing autolysis, bacterial putrefaction, and increasing the tissue's refractive index. The conventional fixative used is 40% formaldehyde. Short-term exposure to formaldehyde can cause irritation to the eyes and respiratory tract, leading to breathlessness and coughing. The International Agency for Research on Cancer (IARC) has classified formaldehyde as a Class 1 human carcinogen capable of potentially causing various neoplasms, including nasopharyngeal carcinoma. Therefore, an innovative approach is being explored to replace formalin with harmless and eco-friendly jaggery. Jaggery possesses cytoprotective, antioxidant, and tissue-preservative properties. At a low pH, the fructose in jaggery breaks down into aldehydes, which cross-link with tissue amino acids, resulting in tissue fixation similar to formaldehyde. Aim: To compare the histological and gross morphological features of tissues fixed in formalin and jaggery. Materials and Methods: This cross-sectional study was conducted in Department of Pathology of a tertiary care centre. Surgical specimens obtained fresh, which were not suspicious of malignancy, were included. A sample size of 23 was selected. Surgical specimens already placed in formalin were excluded. A 30% jaggery solution was prepared by dissolving 300 grams of finely powdered jaggery in 1000 mL of distilled water, which was then filtered using filter paper. A 40% formaldehyde solution was used to prepare a 10% formalin fixative. Tissue bits from each specimen were cut into two halves and placed in formalin and jaggery separately. After 24 hours of fixation, the tissue bits were evaluated for gross morphological features, including tissue shrinkage, consistency, and colour. Tissue shrinkage was classified as mild, moderate, or marked, while consistency ranged from soft to firm to hard. The colour of the specimens varied case by case. Stained slides from jaggery-fixed and formalin-fixed tissues were assessed for histological parameters, such as nuclear details, cytoplasmic details, cellular outline, and overall staining quality. A blinded method was used to compare the stained slides using a microscope. Ratings were assigned to each case on a scale of 1-4. The data were statistically analysed using R software. Results: When comparing the formalin-fixed and jaggery-fixed specimens, no significant differences were observed in gross morphological features. All jaggery-fixed specimens appeared brown grossly. Histological features also showed no significant difference (p-value>0.05) except for cytoplasmic details. Therefore, it was observed that tissue preservation using the jaggery solution was comparable to that of formalin. Conclusion: The tissue-preservative properties of jaggery are on par with formalin. Hence, jaggery solution can be used as an eco-friendly substitute for formalin. Further research with larger sample sizes can pave the way for the effective replacement of hazardous formalin with natural jaggery.

Keywords

• fixative alternative
• formalin substitute
• natural fixative