Experimental data of respiratory and circulatory responses with histopathological changes of spleen to high nitrate ingestion in rabbits

Abstract

ABSTRACT In India, especially in Rajasthan people drink water containing high level of nitrates and concentration up to 500 mg of nitrate ion per liter is not unusual. The ingested nitrate is converted to nitrite in the digestive system and absorb in blood causing methemoglobinemia. Methaemoglobin is not restricted to infants alone but it is prevalent in higher age groups also. The peak of methaemoglobin is observed at 45-95 mg/liter of nitrate concentration of water. Therefore an experimental study was conducted in 10 rabbits between three and half month to four month of age having weight ranging 1.310 kg to 10720 kg. Five groups A, B, C, and D & E were formed with two rabbits in each group. The control group A was given water orally having 06 mg/liter .Group B to E (experimental groups ) were administered water orally having concentration of 100mg/liter,200mg/liter,400mg/liter & 500mg/liter of nitrate respectively for 120 days. During experimental period the difference in general behavior of rabbits were noted. After that rabbits were anaesthetized & sacrificed according to guidelines of ICMR and spleens were removed & processed for paraffin sections, hemotoxyllin and eosin staining was done for microscopic observations. During experimental period, the animals were lethargic on 75th day and and cyanosis appeared on nails, lips, tongue & sclera on 90th day (mainly in rabbits of group D& E). The respiration rate & heart rate were increased with loss of weight. The microscopic study revealed mild congestion of white pulp. In higher groups, the spleen was showing severe red pulp expansion and infiltration of neutrophils in red pulp which appeared from group D.