Hematological and immunohistochemical changes in testes associated with exposure to the formaldehyde Vapor in male rats

Aims: the study was performed to investigate the hematological and immunohistopathological changes in the testes of experimental rats after exposure to formaldehyde. Method: Twenty-four of Albano Waster male rats weighting (150-170g) and grouping into four groups (6 rats for each group). The control group were fed basal diet and given tap water daily for 20 days and not exposed to the formaldehyde vapor . Group two the rats were exposed directly to the vapor of formaldehyde with mean concentration of 1.5 ppm (1 hours daily )for period (20 days) in special chamber . Group three the rats were exposed directly to the vapor of formaldehyde with mean concentration of 1.5 ppm (2 hours daily )for period (20 days) in special chamber. Group four the rats were exposed directly to the vapor of formaldehyde with mean concentration of 1.5 ppm (3 hours daily ) for period (20 days) in special chamber .After end the time of exposure the rats transported to another cages far from the exposure rooms with normal ventilation and normal temperature. Blood samples were individually collected from each rat. Testes organ was immediately removed from experimental rats for immunohistochemical examination and KI67 immunoreactivity. Results: observed significant increase in the weight of the testes in the groups that exposed directly to the formaldehyde vapor with increase the time of exposure as compared with control group in (P< 0.05), significant decrease in (RBCs),(Hb),(HCT),(MCV)and Mean (MCHC) and (Plt) in all groups after exposure to the formaldehyde vapor in different times as compared with control group, in contrast found significant increased in the total (WBCs) most commonly in period times (2,3 hours )of exposure as compared with control group. Ki-67 immunoreactivity (Ki-67-ir) in testes tissue sections were showed strong positive reaction in spermatognia and sertoli cells for Ki-67-ir stain, while the sperms showed negative reaction in control group, moderate positive reactions for Ki-67-ir in spermatognia and sertoli cells after exposure to the formaldehyde vapor for 1 hours daily with disruption in association between sertoli cells and germinal cells, faint positive reaction with (Ki-67-ir) in the spermatogonia and sertoil cells ,while the lydig cells observed moderate to strong positive reaction with (Ki-67-ir) and damage in the somniferous tubules and necrosis of spermatogonia cells with abnormal accumulation of inflammatory cells around the lamina properia after exposure to the formaldehyde vapor for(2 and 3 hours). Conclusion: the exposure to the formaldehyde vapor even in low doses may be attributed haemotoxic and cause dangerous effect on the hematological parameters. Faint positive reaction with Ki-67 stain in spermatiogonia and sertoil cells with moderate or strong positive reaction in the lydig cells after increased the time of exposure to the formaldehyde vapor.