[Establishment and evaluation of lead-exposed osteoporosis model in rats]

Objective: To construct a rat model of osteoporosis induced by lead exposure, simulate the effects of lead exposure on the skeletal system of rats, and provide reliable basic data support for subsequent research. Methods: In July 2021, 40 eight-week-old SPF-grade SD rats were selected and randomly divided into 5 experimental groups according to body weight stratification randomization: blank control group, positive control group, low-dose, medium-dose and high-dose groups, with 8 rats in each group. Continuous intragastric administration (1 ml/100 g) for 60 days was performed respectively with ultrapure water, 0.4 g/L prednisone acetate, 2.0 g/L, 4.0 g/L, and 8.0 g/L lead acetate (PbAc). During the experiment, the general condition and weight changes of the rats were recorded in detail. After model establishment, biological samples of rats were collected. The levels of blood lead, serum calcium, phosphorus, tartrate-resistant acid phosphatase (TRAP) and bone alkaline phosphatase (BALP) in rats were determined. Additionally, micro-computed tomography (Micro-CT) was used to perform 3D reconstruction of the rat femurs and examine ultrastructural changes. One-way analysis of variance was used to compare multiple groups of data, and LSD or SNK methods were used for pairwise comparisons between groups. Results: During the experiment, there were no obvious abnormalities in feeding and drinking, behavioral activities, and fur color of rats in each group, and the body weight maintained normal and gentle growth. Compared with the blank control group, the levels of blood lead, serum calcium, phosphorus, TRAP and BALP in each dose group of PbAc were significantly increased (P<0.05), while the femoral bone mineral density, bone volume/total volume and trabecular thickness were significantly decreased (P<0.05). Compared with the blank control group, the trabecular separation of the femur in the high-dose group was significantly increased, and the trabecular number was significantly decreased (P<0.05). Compared with the blank control group, the bone mass loss of the femur in each dose group of PbAc was severe in rats. Conclusion: PbAc can cause osteoporosis in rats, and osteoporosis assessment indicators such as bone resorption and bone formation markers in rats, femoral bone mineral density and its ultrastructure can all evaluate the success of model construction.