Effect of splenectomy on hepatic tumorigenesis. A morphological study

Abstract

NISHMKAWA AND TAKAGI (1922) suggested an inhibitory influence of the spleen on hepatic regeneration which was later corroborated by the observation of Scnmidt (1924). Later Higgins and Priestley (1932) and more recently PerezTamayo and Romero (1958) and Sengupta and Aikat (1967) have observed that in splenectomised animals, the rate of regeneration of liver after partial hepatectomy was significantly accelerated. Basu and Aikat (1963) observed that splenectomy with or without an appropriate shunt operation in established cases of hepatic cirrhosis produced marked clinical and haematological improvements in a large percentage of the patients. Clinical improvement was characterised by marked morphological improvement as noted in serial biopsies. In their experimental studies they observed that splenectomy could alter the hepatotoxic effect of carbon tetrachloride; so in splenectomised rats cirrhosis could not be produced after continuous administration of carbon tetrachloride. These observations suggested an inhibitory control of spleen on hepatic regeneration after toxic necrosis.The present study was motivated to study the effect of splenectomy on the advent of hepatic neoplasia induced by 3'-methyl-4-dimethylaminoazobenzene (3'-Methyl-DAB) in the rat.Sequential analysis of the advent of hepatic neoplasia both benign and malignant was undertaken mainly by histological characterisation of the lesions produced from early stages up to a period of 20 weeks, when definite microscopic foci of distinctive tumour tissue were encountered. MATERIALS AND METHODSMale and female Wistar rats from the ages of 3 to 4 months and weighing 105 to 150 g. were used. The majority of the rats were raised in the laboratory. They were fed a standard diet, but deficient in riboflavin, and water was given ad libitum.3'-Methyl-DAB was incorporated in a 0-06 per cent concentration in the diet. To ensure total assimilation in a smaller group of rats the drug was emulsified in groundnut oil and was fed through a rubber catheter with the help of a syringe, 6 days a week (6 mg. of carcinogen in 0 5 ml. of oil per rat). The drug was administered to a group of normal rats and a group of rats splenectomised at least one month before the start of the experiment. Splenectomy was performed