Morphological Study on the Mouse Spleen following the Administration of Mercuric Chloride or Potassium Dichromate

Ko, Jeong Sik; Ahn, E Tay; Park, Kyung Ho; Kim, Jin Gook

Abstract

This experiment was performed to study the morphological changes of the spleen of mice following injection of sodium dichromate (K2Cr2O7) or mercuric chloride (HgCl2). Male mice were divided into normal and experimental groups. The mice were subcutaneously injected with mercuric chloride (5 mg or 10 mg/kg) or sodium dichromate (10 mg or 20 mg/kg). Animals were sacrificed on 6 hours, 1 day, 3 days, 1 week and 2 weeks after injections. Pieces of splenic tissue were taken from each mouse, and fixed in 10% neutral formalin for light microscopy. The paraffin sections were stained with hematoxylin-eosin, Masson-trichrome, Bielschowsky's silver impregnation or aldehyde-fuchsin stain. For electron microscopy, the tissues were fixed in 2.5% glutaraldehyde-1.5% paraformalde-hyde, and post-fixed in 1% osmium tetroxide. Dehydrated blocks were embedded in araldite mixture. The ultrathin sections stained with uranyl acetate and lead citrate were observed with JEM 100CX-II electron microscope. On histological study, in the early stage (6 hours) of experimental groups, splenic white pulp exhibited numerous vacuoles containing pyknotic nuclei were observed as compared with those of normal control group. But after 3 days(sodium dichromate, 10 mg/kg or 20 mg/kg; mercuric chloride, 5 mg/kg) and 1 week (mercuric chloride, 10mg/kg), the morphology was recovered to normal one. In the experimental groups, positive reactions to Bielschowsky's silver impregnation, Masson-trichrome or aldehyde-fuchsin stain were similar to those of normal control group. On the ultrastructural study, in white pulps of experimental groups, nuclear bodies were observed frequently in the nuclei of the lymphocytes and the reticular cells, and myelin figures were observed in the nucleus or in the cytoplasm of the lymphocytes and the reticular cells. The plasma cells showed many irregularly distended cisternae of granular endoplasmic reticula and the macrophages containing phagosomes, were observed frequently. From the above results, it was concluded that potassium dichromate or mercuric chloride could disturb the normal differentiation or maturation of the lymphocytes and the reticular cells of the spleen, especially in the early stage of treatment. But histological changes occurred in the spleen following injection of the potassium dichromate or mercuric chloride were recovered to normal appearance in 3 days (potassium dichromate) or 1 week (mercuric chloride). Mercuric chloride was more harmful than potassium dichromate on the spleen.