尼克酰胺对正常大鼠甲状腺辐射增敏作用的实验研究

An Experimental Study on Radiation Sensitizing Effect of Nicotinamide on Normal Thyroid in The Rat

目的观察尼克酰胺(NA)与131Ⅰ联合应用对大鼠甲状腺质量与功能的影响,探讨尼克酰胺对正常大鼠甲状腺的辐射增敏作用。方法雌性SD大鼠48只,体重在180～200g之间,随机分为8组,每组6只。G1组(正常对照组)和G5组(131Ⅰ组)每日每只灌胃生理盐水3ml;G2组(50mgNA组)和G6组(50mgNA+131Ⅰ组)每日每只灌胃NA 50mg;G3组(100mgNA组)和G7组(100mgNA+131Ⅰ组)组每日每只灌胃NA 100mg;G4组(150mgNA组)和G8组(150mgNA+131Ⅰ组)每日每只灌胃NA150mg,持续灌胃30天后G1、G2、G3、G4组行FT3、FT4测定,麻醉下手术取出甲状腺并称重。G5、G6、G7、G8组灌胃每只给予131Ⅰ37MBq,按原方案继续灌胃30天后处理同上。结果 G1、G2、G3、G4组的甲状腺质量无差异(F=2.52,P>0.05)。G5、G6、G7、G8组的甲状腺质量分别与G1相比有统计学意义,且G6、G7、G8的甲状腺质量小于G5具有统计学意义。G1、G2、G3、G4组FT3、FT4四组间差异无意义。G5、G6,G7、G8 4组与G1相比,FT3、FT4减少有统计学意义,且G6、G7、G8的FT3、FT4小于G5具有统计学意义。结论与单独使用131I相比,131Ⅰ与NA联合应用可明显降低大鼠甲状腺的质量及功能,从而进一步证明NA对131Ⅰ作用于大鼠甲状腺具有辐射增敏作用。该实验结果提供了二者联合应用于甲亢和甲癌治疗的可能性。

Objective To observe the influence on rat＇s thyroid weight and function by applying nicotinamide （NA） with 13lⅠ, and investigate radiation sensitizing effect of nicotinamide on normal thyroid in the rat. Methods Totally 48 Female SD rats, 180 - 200g of body weight, were randomly divided into 8 groups with six rats for each one. G1 （control group） and G5 （131Ⅰ） were given physiological sa- line by intragastrie administration, 3ml/d each ; G2 （50mgNA） and G6 （50mgNA ＋ 131Ⅰ） were given NA 50mg/d each ; G3 （100mgNA） and G7（ 100mgNA ＋ 131Ⅰ） were given NA 100mg/d each; G4（150mgNA） and G8（ 150mgNA ＋ 131Ⅰ） were given NA 150mg/d each. The administration were made for 30 days continuously, then FT3, FT4 of the G1 , G2, G3, G4 were measured, meanwhile their thyroids were carefully dissected and weighed under anesthesia. G5, G6, G7, G8 were given 37MBq 131Ⅰ by intragastric administration for each, treated in accordance with the original plan for 30 days, then the same processed as above. Results There was no significant difference in the thyroid weight （TW） of G1, G2, G3, G4. The TW of G5, G6, G7, G8 were significantly lower than that of G1 （P 〈 0.05）. The TW of G6, G7, G8 dwere significantly lower than that of G5 （P 〈 0. 05 ）. There was no significant difference in FT3 and FT4 of G1 , G2, G3, G4. The FT3 and FT4 of G5, G6, G7, G8 were significantly lower than that of G1 （P 〈0.05）. The FT3 and FT4 of G6, G7, G8 were significantly lower than that of G5 （ P 〈 0.05 ）. Conclusion Applying nieotinamide with 131Ⅰ can more significantly reduce the thyroid weight and function of rats than 131Ⅰ alone. Nicotinamide shows its radiation sensitizing effect on normal thyroid in the rat. The results open up the possibilities of the clinical application of the combined treatment with 131Ⅰ and NA for thyroid cancer and hyperthyroidism.