Histopathologic Evaluation of the Effects of Growth Hormone Administration on Growth Plate of pre-Pubertal Rabbit Bones

This study was aimed to evaluate histopathological effects of growth hormone on growth plate of different bones of pre-pubertal rabbits. A total number of 16 white New-Zealand rabbits of 2-4 months age were divided into two groups of eight, the experiment and control groups, and were then caged under the same environmental and nutritional conditions. In the experiment group, 3 Iu/Kg Somatotropin was intramuscularly injected every seven days and control group received the same amount of normal saline.
At the end of study rabbits were euthanized using anesthetic drugs and Radius, Humerus, Femur, Tibia and the first lumbar vertebrae were isolated for histomorphometric examinations.
The results showed that the thickness of growth plate of radius had no significant statistical difference between rabbits of experiment and control groups while this parameter was statistically greater in other bones of the experiment group (P≤0.05). The results of this study showed that long term, low dose somatotropin injection to pre-pubertal rabbits causes thickening of growth plate and helps its longer activity during the growth period of cortical and trabecular bones although its effects is not the same for all bones.