Effects of dexamethasone, celecoxib, and methotrexate on the histology and metabolism of bone tissue in healthy Sprague Dawley rats

Figures & data

Figure 1 Effects of three antiarthritics on body weight of rats.

Notes: Body weight of rats on saline control (Con), dexamethasone 2 mg/kg (Dex), celecoxib 50 mg/kg (Cel), and methotrexate 0.5 mg/kg (MTX) was determined on a weekly basis. Medication started from the second week and lasted until the 14th week. Dex induced weight loss during the period of treatment. No significant body weight changes were found among celecoxib, methotrexate, and control groups.

Table 1 Effects of three antiarthritics treatments on serum biochemical indicators of rats

Group	TRACP (U/L)	Calcium (mg/dL)	Glucose (mmol/L)	Phosphorus (mg/dL)	TG (mg/dL)	TC (mg/dL)	ALP (King unit/100 mL)
Con	3.9±1.5	10.6±1.1	66.1±10.9	7.3±0.7	1.4±0.9	72.6±22.4	10.1±4.9
Dex	7.2±2.2A	9.5±0.7a	98.3±11.8a	5.4±1.1A	0.3±0.07a	50.2±23.3	24.5±21.2
Cel	6.5±1.2a	9.8±0.9	75.5±11.9b	6.9±1.2b	1.3±0.5b	79.7±15.6	11.4±4.4
MTX	N/A	9.6±0.5a	86.2±9.4a	7.2±1.5b	0.9±0.4	76.7±37.9	13.0±6.3

Notes: Total cholesterol (TC), triglyceride (TG), the bone biomarkers alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRACP), calcium, glucose, and phosphorus in serum were determined in rats.

a P<0.05,

A P<0.01 vs Con;

b P<0.05 vs Dex. Values are presented as mean ± standard deviation.

Abbreviations: Con, saline control; Dex, dexamethasone; Cel, celecoxib; MTX, methotrexate; N/A, not applicable.

Table 2 Effects of three antiarthritics on histomorphometric static parameters of the proximal tibial metaphysis

Group	BV/TV (%)	TbTh (μm)	TbN (#/mm)	TbSp (μm)
Con	35.61±5.58	73.50±12.48	4.88±0.37	132.80±15.35
Dex	28.55±2.34a	69.52±7.85	4.31±0.38a	174.37±17.93a
Cel	24.80±5.48A	63.78±10.81	3.86±0.41A	198.00±33.79A
MTX	29.16±3.49a	67.41±4.29	4.33±0.50a	166.49±26.45a,b

Notes: Trabecular bone volume/total tissue volume (BV/TV) and trabecular thickness (TbTh), number (TbN), and separation (TbSp) were determined by bone histomophometry.

a P<0.05,

A P<0.01 vs Con;

b P<0.05 vs Cel. Values are presented as mean ± standard deviation.

Abbreviations: Con, saline control; Dex, dexamethasone; Cel, celecoxib; MTX, methotrexate; #/mm, number per mm.

Table 3 Effects of three antiarthritics on bone formation parameters and osteoclast surface of proximal tibial metaphysis

Group	MS/BS (%)	MAR (μm/d)	BFR/BS (μm/d ×100)	BFR/BV (%/year)	OcS (μm)	OcS/BS (%)
Con	12.19±1.53	0.80±0.03	9.72±1.29	83.04±17.56	0.19±0.06	0.23±0.08
Dex	5.48±0.61A	0.44±0.06A	2.41±0.46A	21.13±3.88A	0.26±0.04a	0.32±0.05a
Cel	12.35±3.61B	0.59±0.15	7.40±3.50B	77.99±53.06B	0.27±0.09a	0.47±0.10A,b
MTX	16.18±3.23a,B,c	1.01±0.27a,b,c	16.44±5.88A,B,c	147.06±47.36a,B,c	0.28±0.04A	0.44±0.09A,b

Notes: The ratio of mineralizing surface to bone surface (MS/BS), the mineral apposition rate (MAR), boneformation rate per unit of bone surface (BFR/BS), bone formation rate per unit of bone volume (BFR/BV) and osteoclast surface (OcS), and osteoclast surface per bone surface (OcS/BS) were determined by bone histomorphometry.

a P<0.05,

A P<0.01 vs Con;

b P<0.05 vs Dex,

B P<0.01 vs Dex;

c P<0.05 vs Cel. Values are presented as mean ± standard deviation.

Abbreviations: Con, saline control; Dex, dexamethasone; Cel, celecoxib; MTX, methotrexate.

Figure 2 Representative micrographs of the proximal tibial metaphysis.

Notes: (A) Goldner’s trichrome stain (1×) and (B) fluorescence images (10×). White arrows point to fluorescence double labeling on the trabecular surface.
Abbreviations: Con, saline control; Dex, dexamethasone; Cel, celecoxib; MTX, methotrexate.

Figure 3 Effects of three antiarthritics on micro-CT parameters of the proximal tibial metaphysis.

Notes: (A) Representative micro-CT photographs of proximal tibial metaphysis (PTM) in rats with different treatments. The red arrows indicate bone loss occurred in the trabecular of proximal tibia. (B) Bone volume/tissue volume (BV/TV); (C) density of TV; bone mineral density of tissue volume; (D) structure model index (SMI); (E) degree of anisotropy (DA). ^aP<0.05, ^AP<0.01 vs Con; ^cP<0.05 vs Cel.
Abbreviations: Con, saline control; Dex, dexamethasone; Cel, celecoxib; MTX, methotrexate; micro-CT, micro-computed tomograph; TV, total tissue volume.

Figure 4 Effects of three antiarthritics on BMD of the femur and the fifth lumbar vertebrae in rats.

Notes: The three antiarthritics, namely Dex, Cel, and MTX caused femur BMD to decrease significantly compared to saline control. No significant difference was found in the BMD of fifth lumbar vertebrae among the three groups. ^aP<0.05, ^AP<0.01 vs Con.
Abbreviations: Con, saline control; Dex, dexamethasone; Cel, celecoxib; MTX, methotrexate; BMD, bone mineral density.

Figure 5 Effects of three antiarthritics on bone biomechanical parameters of femur in rats.

Notes: (A) Effects of three antiarthritics, namely Dex, Cel, and MTX on maximum load and fracture load. (B) Effects of treatments with Dex, Cel, and MTX on energy to maximum load and fracture load. (C) Effects of Dex, Cel, and MTX on bending stiffness. (D) Effects of Dex, Cel, and MTX on elastic load. ^aP<0.05, vs Con; ^bP<0.05 vs Dex.
Abbreviations: Con, saline control; Dex, dexamethasone; Cel, celecoxib; MTX, methotrexate.