Gcwalisile Frances Dlamini; Vaughan Perry; Nhlanhla Lucky Japhta & Robert Ndou

Bone strength is a multifaceted property, with bone geometry (size, length, width, cortical area, and trabecular distribution) providing a critical contribution alongside bone microarchitecture. Therefore, the present study aimed to evaluate the influence of bone geometry and trabecular morphology on tensile strength in a rat humerus. The study used 15 male rats composed of control Sprague Dawley (SD) (n=6) and Zucker Diabetic Sprague Dawley (ZDSD) (n=7). Fasting blood glucose and oral glucose tolerance tests were used to monitor diabetes. Upon termination at 20 weeks of age, humeri were harvested, and a sliding calliper was used for osteometric measurements. Microfocus computed tomography (Micro CT) was performed for assessments of trabecular number (TbN), thickness (TbTh), spaces (TbSp), bone volume (BV), and bone volume ratio (BV/TV) as well as the midshaft cortical and the medullary canal areas. Diabetes was confirmed by deranged fasting blood glucose values and poor oral glucose tolerance finding in the ZDSD group. Diabetic rat humeri had less mass and smaller osteometric dimensions. While the medullary canal and cortical areas as well as the thickness of the trabeculae (TbTh) showed group similarities, the diabetic group exhibited a lower number of trabeculae (TbN) and a greater distance between them (TSp). The geometry of the humerus and trabecular microarchitecture are altered, compromising bone strength and structural integrity in diabetic rats (ZDSD). This should be considered in the overall care for diabetic patients.

KEY WORDS: Humerus; Bone; Diabetes mellitus; Cortical bone; Bone fracture.

DLAMINI, G. F.; PERRY, V.; JAPHTA, N. L. & NDOU, R. The influence of bone geometry and trabecular morphology on tensile strength in the humerus of the Zucker Diabetic Sprague Dawley rat. Int. J. Morphol., 43(4):1442-1448, 2025.