Website: www.aijournals.com/journals/aanat/ DOI: 10.21276/aanat.2017.3.2.4 ORIGINAL ARTICLE ISSN: 2455-5274 Page 15 Effect of Formaldehyde on Rat Testis Structure Abdelmonem Awad Hegazy 1 , Nadia ElAbassery Elsayed 1 , Marwa Mahmoud Ahmad 1 , Nehal Mohammad Omar 1 1 Anatomy and Embryology Department, Faculty of medicine, Zagazig University, Zagazig 44519, Egypt. Date of Submission: 16-07-2017 Date of Acceptance: 26-07-2017 Date of Publishing: 12-09-2017 ABSTRACT Background: Formaldehyde is found in different kinds of medicine and industrial products, cigarette smoke, and even numerous vegetables, fruits and seafood that have been illegally preserved with formalin. The aim of this study was to investigate the effects of formaldehyde on adult albino rat testes through light microscopic examination, immunohistochemistry, biochemistry, morphometry and statistical analysis. Methods: Thirty adult male albino rats were utilized in this work. These animals were equally divided into three main groups, with 10 animals each. Group I (control group): The animals were injected with intraperitoneal sterile physiological saline. Group II animals were injected intraperitoneally with a daily dose of formaldehyde (5 mg/kg body weight "BW") for 30 days. Group III animals were injected intraperitoneally with a daily dose of formaldehyde (10 mg/kg BW) for 30 days. By the end of the experiment, blood samples were collected for biochemical study of testosterone; and all animals were anaesthetized and testis specimens were dissected out and weighted then subjected to histological, immunohistochemistry, and morphometric examination. Results: Administration of formaldehyde at a dose of 5 and 10 mg/kg caused a decrease in serum testosterone. Moreover, it caused a decrease in the testis weights and induced several histopathological changes in the testis of adult male albino rats such as atrophy of seminiferous tubules with absence of sperm bundles and degeneration of germ. It also increased the collagen fibers deposition in testis as evidenced by Masson`s trichrome staining. The testis showed a positive immune reaction to 8-hydroxy-2'-deoxyguanosine. Conclusion: Exposure to formaldehyde is suggested to result in some testicular damage. It is suggested that special precautions might be taken to limit the occupational and environmental formaldehyde exposure; and to prevent or even minimize its contamination with food and water. Keywords: Formaldehyde, Testis, Structure, Light microscopy, Rat. INTRODUCTION Formaldehyde (FA) is a colorless and highly water- soluble aldehyde. Its intake occurs through the topical, oral, injection and mostly via the respiratory system. It can be inhaled with smokes due to the combustion of burning fossil fuels and in the fumes of paints and in cigarette smoke. [1] It can be ingested in fresh water, food and drugs. In food, it can occur naturally or through contamination as it can be added as a preservative or disinfectant agent. It can also result from cooking or smoking of foods. [2] Even in infancy, the babies might be exposed by injection to FA present in diphtheria, polio and tetanus vaccine preparations as a result of the manufacturing process. [3] Several malignancy treating drugs are formulated with FA which is required for drug activation. [4] Some cosmetics especially hair smoothing products containing FA or methylene glycol which require the use of heat that leads to volatilization of both FA gas as well as methylene glycol vapors. This increases the potential for hair stylist and consumer exposure to FA from methylene glycol formulated in keratin products. [5] Name & Address of Corresponding Author Abdelmonem Awad Hegazy, Anatomy and Embryology Department, Faculty of medicine, Zagazig University, Zagazig 44519, Egypt. E. Mail: dr.abdelmonemhegazy@yahoo.com Cell phone: +201110504321 Formaldehyde is an organic carbon compound which receives an increasing attention as pollutants with potential adverse health effects. [6] It induces oxidative stress which has been reported to be the mechanism of