Radioprotective Effects of Histamine H2 Receptor Antagonists Famotidine and Ranitidine on Gamma-Ray Induced Chromosome Aberration and Micronuclei in vitro in Human Lymphocytes

Histamine H2 receptor antagonist are used in the clinical treatment of peptic ulcer. In vitro metaphase analysis and micronucleus assay were used to test the effect of Famotidine & Ranitidine on 60 Cobalt gamma-ray induced clastogenic effects. Heparinised whole blood was obtained from 6 healthy volunteers and was gamma irradiated with 3Gy. Lymphocyte cultures were initiated and aqueous solution of Famotidine (150μg/ml) & Ranitidine (500μg/ml) was added at 0h and 24h. Cultures were harvested & processed at 48h & 72h for chromosome aberrations and micronucleus analysis respectively. At 0h & 24h after 3Gy gamma irradiation, cultures treated with Famotidine & Ranitidine independently showed significant decrease (p < 0.0001) in the frequency of chromosome aberration. At 0h & 24h Famotidine induced 60.91% & 56.42% inhibition in dicentrics & 59.39% & 56.21% inhibition was observed in total aberrations where as Ranitidine induce 52.11% & 43.54% inhibition in dicentrics and 53.06% & 46.66% inhibition in total aberrations at 0h & 24h. Significant decrease in the frequency of micronuclei was observed with Famotidine treatment after 3Gy of gamma irradiation, which induced inhibition of 48.83% (p < 0.0001) at 0hr & 5.02% (p < 0.016) at 24h. However, Ranitidine induced significant decrease (p < 0.0001) in frequency of micronuclei of 28.85% at 0h where as a decrease in frequency was observed of 2.88% at 24h although not significant when compared with 3Gy gamma irradiation alone. In conclusion radio protective effects of Histamine H2 receptor antagonists Famotidine and Ranitidine was observed on exposure to gamma-ray.