[Effect of early vitamin D supplementation on lung inflammatory factors in baby rat with asthma].

Objective: To explore the effect of different doses of 1,25-(OH)(2)VitD(3) early supplementation on airway inflammation and lung inflammatory factors in baby rats with asthma.
Methods: Forty male weaned Wistar rats were divided into normal group, model group, low 1,25-(OH)(2)VitD(3) group, middle 1,25-(OH)(2)VitD(3) group, high 1,25-(OH)(2)VitD(3) group using random number table (8 rats each group). The rats in low, middle and high 1,25-(OH)(2)VitD(3) groups were given 1, 4, 10 µg/kg of 1,25-(OH)(2)VitD(3) every other day by intraperitoneal injection respectively for 25 days. Except normal group, the rats in other groups were challenged with ovalbumin to establish the asthma model. The pathologic changes of lung tissue, the total white blood cell and classified cell counts in bronchoalveolar lavage fluid (BALF) were measured. The concentrations of IL-4, IL-5 and IFN-γ in serum and BALF were measured by ELISA method.
Results: The level of total white blood cell counts in BALF were (5.98 ± 1.67)×10(5)/ml, (25.34 ± 4.28)×10(5)/ml, (17.24 ± 3.3)×10(5)/ml, (9.31 ± 3.37)×10(5)/ml, (45.1 ± 15.75)×10(5)/ml, respectively (F = 33.453, P < 0.01). The percent ratio of EOS in BALF were (1.44 ± 0.78)%, (17.81 ± 6.88)%, (15.00 ± 5.70)%, (8.89 ± 3.66)%, (25.88 ± 5.57)%, respectively (F = 27.299, P < 0.01). The level of IL-4 in serum of normal, model, low, middle and high-1,25-(OH)(2)VitD(3) groups were (0.62 ± 0.54), (7.57 ± 1.04), (3.58 ± 0.56), (2.70 ± 0.78) and (5.27 ± 0.30) pg/ml, respectively (F = 116.287, P < 0.01); IL-5 in resume were (32.20 ± 4.23), (67.14 ± 18.14), (37.51 ± 0.47), (40.69 ± 2.47) and (124.60 ± 36.19) pg/ml, respectively (F = 23.902, P < 0.01); IFN-γ in serum were (79.71 ± 10.08), (49.06 ± 4.46), (59.15 ± 2.51), (59.27 ± 2.33) and (53.85 ± 1.97) pg/ml, respectively (F = 39.954, P < 0.01). Also in BLAF, the IL-4 of all groups were (0.51 ± 0.30), (102.92 ± 54.61), (8.64 ± 4.07), (3.10 ± 1.28) and (33.67 ± 8.1) pg/ml, respectively (F = 24.062, P < 0.01); the IFN-γ were (247.37 ± 189.18), (43.82 ± 13.76), (81.32 ± 17.07), (86.50 ± 14.26) and (59.89 ± 34.17) pg/ml, respectively (F = 7.157, P < 0.01); the IL-5 in BALF were (38.81 ± 0.60), (80.48 ± 17.90), (45.11 ± 1.33), (43.39 ± 1.11) and (149.60 ± 45.87) pg/ml, respectively (F = 35.978, P < 0.01). Pathologic changes in lung of asthma rat groups were obvious. The lung pathologic changes in low and middle dose groups showed a significant improvement compared to the asthma group and high dosage group showed more serious pathologic changes compared to the low and middle dose groups.
Conclusion: Intervention with appropriate dose of 1,25-(OH)(2)VitD(3) in the early life could improve lung pathologic changes and reduce the effect of inflammatory factors in air way of baby rat asthma model. However, overdose might play detrimental effect.