RESUMEN
Aim: Costus afer is a medicinal plant used as a therapy for diabetes and hypertension. This study investigated the effect of crude ethanolic extract of Costus afer (Monkey sugar cane) stem and its juice on the histology of the spleen and some blood parameters of albino wistar rats. Place and Duration of Study: This study was carried out in the Department of Human Anatomy, University of Calabar, Nigeria for four weeks. Methodology: Twenty four (24) rats were divided into four groups of six (6) animals each. Group one (I) served as control, Group two (II) served as experimental group and received 200 mg /kg body weight (low dose) of the crude ethanolic extract. Group three (III) also served as experimental group, tested with 500 mg/kg body weight (high dose) of the crude ethanolic extract and Group four (IV) was tested with 5 mls /kg body weight of Costus afer stem juice. Treatment was orally using orogastric tube for twenty eight (28) days after which the animals were sacrificed within twenty four hours after the last dose. Results and Conclusion: Results showed no morphological changes. Histological sections of the spleen from experimental animals in the control group showed normal histology of the spleen with well distinct lymphatic tissue. Sections of the spleen from animals tested with 200 mg /kg ethanolic extract showed no pathological changes compared with the control group. Sections of the spleen from animals tested with 500 mg/kg body weight of the crude ethanolic stem extract were observed to have more red pulp than the white pulp. Animals tested with 5mls /kg body weight of Costus afer stem juice showed no pathological observations. Hematological observations showed decreased Packed Cell Volume (PCV) and increased Platelet count (P =.05), but had no significant effect on total white blood cell count and differential count. In conclusion, Costus afer at the administered dose had no pathological effect on the spleen histology, but increased platelet count and decreased packed cell volume.