Comparative Evaluation Of Formaldehyde, Modified Thiel, And Saturated Salt Solution (SSS) For Embalming In Wistar Rats: A Morphological, Microbial And Histological Study

Background & objectives: Embalming is the process of artificial preservation of dead body with the help of different chemicals. Formaldehyde is the traditional embalming chemical that works effectively, but it raises health and environmental concerns. Other alternatives, such as the Thiel and Saturated Salt Solution (SSS), show potential benefits with enhanced safety and preservation of tissue. Nonetheless, comparative research is scarce, especially involving animal studies. This study aims to evaluate and compare the embalming effectiveness of formaldehyde, Modified Thiel, and SSS in Wistar rats over a 16-week duration, concentrating on morphological preservation, resistance to microorganisms, and maintaining the histological integrity. Methods: A total of 54 Wistar rats were divided randomly into three groups (n=18 each), with Group A treated with formaldehyde, Group B with Modified Thiel solution, and Group C treated with Saturated salt solution(SSS). The embalming process involved carotid perfusion followed by immersion in the designated embalming fluid. Evaluations of morphological features, microbial resistance, and histological analysis of superficial and internal organs were conducted at weeks 1, 8, and 16. Grading was conducted by six evaluators who were blinded to the groups, and statistical analysis was performed using the Kruskal-Wallis test and Fleiss' Kappa. Results: In terms of morphology, the SSS group maintained a color and tonicity that was close to natural at all time points, followed by the Thiel method, while formaldehyde performed the least with tissue hardening and discoloration. The joint range of motion was highest in the SSS group and lowest in the group embalmed with formaldehyde. No microbial growth was detected in any of the embalming solutions. In the histological assessments, at the end of the 16 weeks, SSS showed superior preservation across the majority of organs, while formaldehyde exhibited the most degeneration. Conclusion: SSS emerged as the most effective embalming method of the three, providing superior preservation of physical characteristics, joint mobility, and histological integrity over the 16 weeks. Modified Thiel exhibited moderate efficacy, while formaldehyde, despite its antimicrobial properties, proved to be the least effective over time. These results advocate for the use of safer and more functional embalming alternatives, such as SSS, in anatomical education and research.