 Corresponding author: Ayman Saber Mohamed Copyright © 2023 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0. Histopathological examination of Allolobophora calignosa efficacy against glucocorticoid-induced osteoporosis in mice Marwa Ahmed Abdelfattah, Ayman Saber Mohamed * , Sherif Abdelaziz Ibrahim and Sohair R. Fahmy Department of Zoology, Faculty of Science, Cairo University 12613, Giza, Egypt. GSC Biological and Pharmaceutical Sciences, 2023, 22(01), 125–133 Publication history: Received on 25 November 2022; revised on 09 January 2023; accepted on 11 January 2023 Article DOI: https://doi.org/10.30574/gscbps.2023.22.1.0499 Abstract Osteoporosis is a disease characterized by low bone mass, deterioration of bone tissue, and disruption of bone microarchitecture: it can lead to compromised bone strength and increased risk of fractures. Secondary osteoporosis is mostly glucocorticoid-induced osteoporosis (GIOP). According to traditional Chinese medicine, the kidney influences bone, and bone loss are associated with kidney and liver inadequacies. We tested Allolobophora caliginosa extract (EE) and Allolobophora caliginosa coelomic fluid (CF) for anti-osteoporotic activity against GIOP. 28 male mice were separated randomly into two groups; the control received distilled water, and the second group received 1 mg/kg dexamethasone daily for 28 days. The second group was divided randomly into three groups. The first OP subgroup received distilled water orally every other day for 28 days. The other two OP subgroups received EE (45 mg/kg body weight) and CF (20 mg/kg) orally for 28 days. EE and CF preserved cortical and trabecular bone loss, decreased bone marrow space, and enhanced chondrocyte production. EE and CF maintained hepatic necrosis in the liver and decreased renal degeneration in the kidney caused by GIOP. In this study, Histological images showed that EE at 45 mg/kg was highly effective as an anti-osteoporotic against GIOP, while CF at 20 mg/kg was moderately effective. Keywords: Glucocorticoids; Osteoporosis; Earthworm; Antiosteoporosis 1. Introduction Bone is a valuable, living tissue that alters all the time. This process aims to replace the old micro-damaged bones with new, stronger ones (1). This procedure is done with groups of osteoclasts, which break down bone, and osteoblasts, which build up the bone (2). Osteoporosis (OP) is characterized by a loss of bone mass and deterioration of bone structure (3). This causes bones to be thin, directly affecting cortical porosity, bone fragility, and the risk of breaking a bone (4). Many factors contribute to the risk of osteoporosis and fracture associated with aging; hormonal factors, limited physical activity, a lack of physical activity, a lack of calcium or vitamin D, pharmacological therapy such as glucocorticoids (GCs), and inherited features (5). GCs are widely utilized to treat various systemic disorders as they are important anti-inflammatory and immunosuppressive agents (6). In contrast, long-term use of GCs promotes bone loss and osteoporosis by killing osteocytes and osteoblasts (7) and increases reactive species generation, producing skewed bone remodeling and an imbalance between osteoclasts and osteoblasts (8). Furthermore, GCs indirectly affect bone by lowering gastrointestinal calcium absorption and increasing renal calcium loss, altering calcium homeostasis.