Amelioration of adjuvant-induced arthritis by exposure to low dose gamma radiation and resveratrol administration in rats

Figures & data

Figure 1. Effect of different low dose radiation exposure regimens on the paw volume in FCA-induced arthritic rats. Rats were exposed to a total exposure level of 0.5 Gy applied either single (1 × 0.5 Gy at day 14) or split (2 × 0.25 Gy at days 14&21 or at days 21&28). Results are expressed as mean volume of edema ± SEM (n = 8/group).

Table 1. Effect of different low dose radiation exposure regimens on the paw volume in in the Freund’s complete adjuvant-induced arthritic rats.

Parameter	Paw volume (mL)
Groups	Day 0	Day 4	Day 8	Day 12	Day 16	Day 20	Day 24	Day 28
Freund's comple’e adjuvant (FCA)
Control	0.690 ± 0.010	1.988 ± 0.096	1.845 ± 0.108	1.848 ± 0.117	1.718 ± 0.091	1.697 ± 0.060	1.665 ± 0.063	1.663 ± 0.062
1 × 0.5 Gy (day 14)	0.756 ± 0.031	2.210 ± 0.160	2.054 ± 0.065	1.958 ± 0.052	1.804 ± 0.039	1.914 ± 0.035	1.872 ± 0.016	1.868 ± 0.028
2 × 0.25 Gy (days 14&21)	0.691 ± 0.048	2.058 ± 0.158	1.792 ± 0.101	1.763 ± 0.064	1.603 ± 0.063	1.658 ± 0.066	1.603 ± 0.067	1.573 ± 0.076
2 × 0.25 Gy (days 21&28)	0.718 ± 0.023	2.096 ± 0.056	1.901 ± 0.049	1.841 ± 0.073	1.677 ± 0.057	1.763 ± 0.074	1.673 ± 0.063	1.729 ± 0.073

Rats were exposed to a total exposure dose level of 0.5 Gy applied either single (1 × 0.5 Gy at d 14) or split (2 × 0.25 Gy at days 14&21 or at days 21&28). Results are expressed as mean paw volume ± SEM (n = 8/group).

Table 2. Effect of different low dose radiation exposure regimens on the serum levels of pro-inflammatory cytokines and oxidative stress markers in the Freund’s complete adjuvant-induced arthritic rats.

Groups	TNF-α (pg/mL)	IL-1β (pg/mL)	TBARs (nmol/mL)	NOx (nmol/mL)
Normal	134.50 ± 6.39	131.42 ± 9.25	1.46 ± 0.047	7.34 ± 0.78
FCA	398.00 ± 6.59	271.42 ± 25.58	4.81 ± 0.15	54.29 ± 3.48
FCA +1 × 0.5 Gy (day 14)	349.33 ± 28.77	215.14 ± 10.96	4.89 ± 0.13	54.05 ± 5.20
FCA + 2 × 0.25 Gy (days 14&21)	287.00* ± 26.24	193.71* ± 18.66	3.79* ± 0.31	31.87* ± 2.85
FCA + 2 × 0.25 Gy (days 21&28)	360.66 ± 26.38	223.42 ± 16.82	4.86 ± 0.22	53.14 ± 5.34

Rats were exposed to a total exposure dose level of 0.5 Gy applied either single (1 × 0.5 Gy at day 14) or split (2 × 0.25 Gy at days 14&21 or at days 21&28). Results are expressed as mean ± SEM (n = 8/group). *p < .05 compared to FCA group.

Figure 2. Effect of low dose radiation exposure (2 × 0.25 Gy, days 14&21) and RSV (50 mg/kg) administration on the paw volume in FCA-induced arthritic rats. RSV and diclofenac were given orally for two weeks started from day 14. Results are expressed as mean volume of edema ± SEM (n = 8/group). ^@p < .05 compared to FCA group.

Table 3. Effect of low dose radiation exposure and resveratrol administration on the paw volume in the Freund’s complete adjuvant-induced arthritic rats.

Parameter	Paw volume (mL)
Groups	Day 0	Day 4	Day 8	Day 12	Day 16	Day 20	Day 24	Day 28
Freund’s complete adjuvant (FCA)
Control	0.896 ± 0.031	2.420 ± 0.044	2.225 ± 0.044	2.243 ± 0.064	2.215 ± 0.074	2.200 ± 0.0491	2.190 ± 0.048	2.191 ± 0.028
Irradiation (2 × 0.25 Gy)	0.903 ± 0.015	2.477 ± 0.101	2.255 ± 0.053	2.292 ± 0.082	2.188 ± 0.090	2.182 ± 0.083	2.088 ± 0.064	2.080 ± 0.059
Resveratrol (RSV) (50 mg/kg)	0.941 ± 0.034	2.615 ± 0.113	2.430 ± 0.113	2.380 ± 0.117	2.253 ± 0.096	2.247 ± 0.095	2.192 ± 0.114	2.202 ± 0.111
Irradiation + RSV	0.883 ± 0.023	2.398 ± 0.083	2.235 ± 0.081	2.212 ± 0.082	2.138 ± 0.081	2.052 ± 0.093	1.867* ± 0.069	1.848* ± 0.077
Diclofenac (3 mg/kg)	0.938 ± 0.018	2.585 ± 0.011	2.372 ± 0.113	2.352 ± 0.102	2.255 ± 0.105	2.197 ± 0.104	1.943* ±0.056	1.890* ± 0.041

Rats were exposed to split irradiation (2 × 0.25) at days 14&21. RSV and diclofenac were administered orally for two weeks started from day 14. Results are expressed as mean paw volume ± S.E. (n = 8/group). *p < .05 compared to FCA group.

Figure 3. Effect of low dose radiation exposure (2 × 0.25 Gy, days 14&21) and RSV (50 mg/kg) administration on the serum levels of TNF-α (a) and IL-1β (b) in FCA-induced arthritic rats. RSV and diclofenac were given orally for two weeks started from day 14. Results are expressed as mean ± SEM (n = 8/group). ^#p < .05 compared to Normal group. ^@p < .05 compared to FCA group. *p < .05 compared to irradiated group.

Figure 4. Effect of low dose radiation exposure (2 × 0.25 Gy, days 14&21) and RSV (50 mg/kg) administration on the serum levels of TBARs (a) and NOx (b) in FCA-induced arthritic rats. RSV and diclofenac were given orally for two weeks started from day 14. Results are expressed as mean ± SEM (n = 8/group). ^#p < .05 compared to Normal group. ^@p < .05 compared to FCA group. *p < .05 compared to irradiated group.

Figure 5. Representative sections of ankle joint stained with hematoxylin and eosin (H&E magnification x200) of (a) Normal group, (b) FCA group, (c) FCA + Irradiated (2 × 0.25 Gy, days 14&21) group, (d) FCA + RSV (50 mg/kg) group, (e) FCA + Irradiated + RSV group and (f) FCA + diclofenac (3 mg/kg) group. (g) Tissue sections were scored individually for infiltration of inflammatory cells (large arrow), synovial proliferation, pannus formation (small arrow) and cartilage damage (arrow head) on a scale 0–3. (h) Total histological scoring of joints was evaluated and the sum of all mean scores was calculated. (i) Number of inflammatory cells/microscopic field. Results are expressed as mean ± SEM (n = 8/group). ^#p < .05 compared to Normal group. ^@p < .05 compared to FCA group. *p < .05 compared to irradiated group.

Figure 6. Immuno-histochemical analysis (magnification x400) of the NF-κB p65 expression in synovial tissues of (a) Normal group, (b) FCA group, (c) FCA + irradiated (2 × 0.25 Gy, days 14&21) group, (d) FCA + RSV (50 mg/kg) group, (e) FCA + irradiated + RSV group and (f) FCA + diclofenac (3 mg/kg) group. (g) Quantitative analysis of NF-κB p65 expression in synovial tissues of normal, arthritic and treated groups. Results are expressed as mean percentage of expression area ± SEM (n = 8/group). ^#p < .05 compared to Normal group. ^@p < .05 compared to FCA group. *p < .05 compared to irradiated group.