The Effects of Endosulfan on the Testes of Bluegill Fish, Lepomis macrochirus: A Histopathological Study

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The effect of endosulfan, an Organochlorine pesticide, on bluegill testes was studied. Endosulfan is aqua-toxic and has an immediate effect on fish and other aquatic life. In this experiment, we exposed the fish for 24-, 48-, 72-, 96-h, and 1- and 2-week periods. A second group of fish without exposure to endosulfan served as the control. The control testis appeared structurally normal. The seminiferous tubules were of round or oval shape and contained primary spermatogonia, primary spermatocytes, secondary spermatocytes, spermatozoa, spermatids, Sertoli cells, and interstitial cells of Leydig. Within the connective tissue that connected the seminiferous tubules were Leydig cells. After 24 h of exposure, there was evidence of slight signs of connective tissue splintering. The 48-h exposure resulted in breakage of primary spermatocyte walls and separation from the seminiferous tubules. The 72-h testis showed further connective tissue damage and migration of primary spermatogonia into the lumen. After 96 h, there was significant damage to connective tissue and the seminiferous tubules were less pronounced. After 1 and 2 weeks, the seminiferous tubule walls were disrupted and missing in places and the structure of the testis was very disorganized compared to the control testis. Biometric analysis indicated that the diameter of the primary spermatogonia decreased from 24 h to two weeks. There also appeared to be fewer Leydig cells, responsible for testosterone production, over the exposure period and damaged Sertoli cells, which support, protect, and nourish the spermatogenic cells, synthesize ABP, and assist in maintaining the necessary concentration of testosterone in the seminiferous tubules so that spermatogenesis can progress. These kinds of damage could affect the spermatids and spermatozoa and possibly have a negative impact on spermatogenesis and male fertility, affecting bluegill fish population.