The Effect Of Formaldehyde On The Lymphoid Tissues Of Rats( Quantitatine And Histological Study)

Abstract

This study is concerned with the effect of formaldehyde on the lymphoid system by
quantitative and histological analysis. For this purpose 4 groups , each of 8 male rats were
examined , group I lefts as a control , while group II,III and IV had given oral administration of
10% formaldehyde (10 mg /kg body weight /day ) for 30, 60 and 90 days respectively . Two
lymphoid organs , spleen and iliac lymph node were examined . The results showed
significantly decreased of body weight during long period of formaldehyde exposure . In
general a significant decrease were observed in organ weight , standardized weight , total white
cell count , cell density and differential white cell count in the treated groups and especially
during long period of exposure. Histologically, a significant decrease was observed in the number
and the percentage of while pulp of spleen, and in the number of nodules and the percentage of the
diameter of the cortex of the iliac lymph node. These results showed that the formaldehyde caused
a marked involution of the lymphoid system and this might be due to decreasing in cell-mediated
immunity and humoral immunity leading to immunosuppression.