Eur J Anat, 18 (4): 283-290 (2014)

Cardiac adaptation in prolonged inverted bats (Eidolon helvum)

James O. Ashaolu and M.S. Ajao

Department of Anatomy, Faculty of Basic Medical Sciences, College of Health Sciences, University of Ilorin, Kwara State, Nigeria

ABSTRACT Inversion (head-down positioning) is often the regular resting position for some species of bats. The objectives of the study was are to determine the differences in body weight, relative heart weight; serum cardiac troponin I and creatine kinase MB; and cardiac left ventricular general histology, deoxyribonucleic acid (DNA) synthesis, elastic fibre and collagen fibres, glycogen accumulation, fat accumulation in bats exposed to prolonged inversion. Bats obtained from Bowen University roosting colony, Osun State, Nigeria were grouped into A, B, C and D with each group containing ten bats. The bats were sacrificed at first, eight, fifteenth, twenty-second day of experiment respectively. Blood samples collected for the estimation of cardiac troponin I and creatine kinase MB. Histological examination of the left ventricle was done using Haematoxylin and Eosin and other stains. The results showed elevation of cardiac function markers (cTnI and CK-MB) indicated cardiac myocyte damage and increased energetics was associated with prolonged inversion in bats. Histological findings revealed mechanically-stressed heart muscles which later adapted followed by myocyte regeneration. The study concludes that bats cardiac tissue possess positive adaptation to prolonged inversion and could become a suitable ground-based model for simulating microgravity while for bat laboratory acclimatization protocols need to be revisited.

Keywords: Bats, Inversion, Cardiac hypertrophy, Heart