齐墩果酸抗矽肺大鼠TNF-α和胶原表达的实验研究

目的:观察齐墩果酸对矽肺大鼠肿瘤坏死因子α(TNF-α)和胶原表达的影响及其可能作用机制。方法:80只SPF级Wistar雄性大鼠,随机分为对照组、模型组、齐墩果酸组和溶剂组,每组20只。除对照组外,其余组大鼠采用非暴露法气管内一次性注入Si O2悬液(250 mg/kg)复制动物矽肺模型。齐墩果酸组自注射Si O2后每天给予齐墩果酸60 mg/kg灌胃,溶剂组每天用0.6%羧甲基纤维素钠溶液(10 m L/kg)灌胃,对照组用生理盐水(10 m L/kg)灌胃,连续56 d。动物分别在注射Si O2后第7、14、28和56天处死(每次每组5只)。处死后检测各组大鼠肺系数,并观察形态学变化;应用ELISA法检测大鼠血清中TNF-α的含量;试剂盒检测肺组织中总胶原蛋白含量;免疫组织化学法检测肺组织核因子κB(NF-κB)表达。结果:(1)与对照组比较,模型组和溶剂组大鼠肺系数和总胶原蛋白含量明显升高,结合形态学变化,矽肺模型造模成功。齐墩果酸组各时点肺系数和总胶原蛋白含量比模型组和溶剂组相应时点低,但比对照组高。(2)模型组和溶剂组大鼠血清中的TNF-α含量各时点明显升高,高峰在第14天,之后稍降,但明显高于对照组,差异有统计学意义;模型组与溶剂组各时点比较,差异无统计学意义。齐墩果酸组TNF-α含量与模型组相比均降低,各时点比较差异有统计学意义。(3)模型组和溶剂组大鼠肺组织中NF-κB表达量逐渐升高,至第28天达高峰,各时点与对照组比较差异均有统计学意义。齐墩果酸组的NF-κB阳性表达趋势与模型组相同,但明显低于模型组而高于对照组,各时点与对照组比较差异有统计学意义。结论:齐墩果酸通过抑制TNF-α和胶原表达减缓矽肺纤维化的发生,可能与NF-κB通路有关。

Effect of oleanolic acid on expression of TNF-α and collagen in silicotic rats in vivo

AIM: To observe the effect of oleanolic acid (OA) on the expression of Tumor necrosis factor-α (TNF-α) and collagen in silicotic rats in vivo and its possible mechanism. METHODS: Male Wistar rats were divided into 4 groups according to the randomized block design: control group, model group, OA group and solvent control group (20 rats in each group). Except control group, the rats in other groups were induced by intratracheal instillation of silicon di-oxide (SiO₂; 250 mg/kg). The rats in OA group were intragastrically administered with OA (60 mg/kg) from the second day of giving SiO₂. The rats in solvent control group were gavaged daily with 0.6% sodium carboxymethyl cellulose solution (10 mL/kg). The rats in control group were given normal saline under the same condition for 56 consecutive days. All rats were killed at the 7th, 14th, 28th and 56th days. The lung coefficient was detected and the morphological changes were observed. The serum contents of TNF-α were detected by ELISA. The content of total collagen in the lung tissue was measured. The protein level of nuclear factor-κB (NF-κB) in the lung tissue was determined by immunohistochemical method. RESULTS: (1) According to the morphological changes, the silicosis model was successfully established. Compared with control group, the lung coefficient and total collagen increased obviously in model group and solvent control group. The lung coefficient and total collagen content in OA group at each time point reduced compared with those in model group and solvent group, and increased compared with those in control group at the corresponding time points. (2) The serum contents of TNF-α in model group and solvent control group significantly increased, peaking at the 14th day, slightly decreasing afterward, and showing statistically significant difference at each time point compared with those in control group. No significant difference between model group and solvent group at different time points was observed. OA had inhibitory effect on the contents of TNF-α compared with model group and solvent group at the corresponding time points. (3) NF-κB in model group and solvent control group significantly increased, peaking at the 28th day, and showing statistically significant difference at each time point compared with those in control group. The NF-κB expression in OA group was similar to model group, but significantly decreased compared with control group at each time point. CONCLUSION: OA inhibits the expression of TNF-α and collagen and attenuates the silicosis fibrosis, which may be related to the NF-κB pathway.