卵泡抑素对肿瘤恶病质小鼠骨骼肌消耗的影响及其作用机制

摘要

目的：观察卵泡抑素（FST）对肿瘤恶病质小鼠骨骼肌消耗及肌肉生长抑制素（Mstn）、长链非编码 RNA （LncRNA）-肺癌转移相关转录本1（MALAT1）和 Caspase-3表达的影响，阐明其缓解肿瘤恶病质小鼠骨骼肌消耗的可能机制。方法：32只 BALB／c 小鼠随机分为健康对照组（HC 组）、FST 预防组（FP 组）、FST治疗组（FT 组）和肿瘤恶病质组（CC 组），每组8只，后3组小鼠皮下接种小鼠结肠癌 CT26细胞诱导肿瘤恶病质。监测各组小鼠体质量、自发性活动量和肿瘤生长情况。于接种后第6、12天 FP 和 FT 组小鼠分别给予FST （5μg· kg－1·d－1）腹腔注射。第20天采集标本，称肿瘤及腓肠肌质量，检测小鼠血清生化代谢指标及腓肠肌纤维横切面积，Real-time PCR 法检测小鼠腓肠肌和肿瘤组织中 Mstn、Caspase-3及 LncRNA-MALAT1 mRNA 表达水平，Western blotting 法检测小鼠腓肠肌组织中 Mstn 和 Caspase-3蛋白表达水平。结果：与 CC 组比较，FP 和 FT 组小鼠体质量、自发性活动量、腓肠肌质量及其肌纤维横切面积均增加（P ＜0.05），生化代谢指标改善（P ＜0.05）。与 HC 组比较，CC 组小鼠腓肠肌组织中 Mstn 和 Caspase-3 mRNA 及蛋白表达水平均升高（P ＜0.05），LncRNA-MALAT1 mRNA 表达水平降低（P ＜0.05）；与 CC 组比较，FP 和 FT 组小鼠腓肠肌组织中 Mstn 和 Caspase-3 mRNA 及蛋白表达水平均降低（P ＜0.05），LncRNA-MALAT1 mRNA 表达水平升高（P ＜0.05），且 FP 组预防效果优于 FT 组（P ＜0.05）。结论：FST 可缓解肿瘤恶病质小鼠骨骼肌消耗，其机制可能与抑制 Mstn 表达、上调 LncRNA-MALAT1表达从而降低 Caspase-3表达有关。%Objective: To observe the effects of follistatin (FST)on the skeletal muscle wasting of cancer cachexia mice and the expressions of Mstn, LncRNA-MALAT1 and Caspase-3, and to elucidate its associated molecular mechanisms.Methods:Thirty-two BALB/c mices were randomly assigned into:healthy control (HC) group,FST prevention (FP)group,FST treatment (FT)group and cancer cachexia (CC)group.The murine colon adenocarcinoma CT26 cells were inoculated subcutaneously into the mices in FP, FT and CC groups to establish the cancer cachexia models. The body weight, spontaneous activity and tumor growth were daily monitored.The mice in FP and FT groups were administrated with FST intraperitoneally on day 6 and 12 after inoculation.The samples were collected on day 20.The tumor and gastrocnemius weights of the mice were detected. The biochemical metabolism indexes and myofiber cross-sectional area of gastrocnemius tissue were detected.The mRNA expression levels of Mstn,Caspase-3 and LncRNA-MALAT1 were examined by Real-time PCR.The protein expression levels of Mstn and Caspase-3 were measured by Western blotting method. Results:Compared with CC group,the body weights,spontaneous activities,gastrocnemius weights and myofiber cross-sectional areas were increased (P <0.05);the serum levels of glucose,total protein and albumin of the mice in FP and FT groups were increased (P <0.05).The protein and mRNA expression levels of Mstn and Caspase-3 in gastrocnemius of the mice in CC group were significantly higher and the expression level of LncRNA-MALAT1 was significantly lower than those in HC group (P < 0.05).The mRNA and protein expression levels of Mstn and Caspase-3 in FP and FT groups were reduced and the expression level of LncRNA-MALAT1 was increased compared with CC group (P < 0.05).The prevention effect in FP group is better than FT group (P < 0.05). Conclusion:FST may alleviate the muscle wasting of the mice with cancer cachexia by inhibiting the expression of Mstn,thus upregulating the expression of LncRNA-MALAT1 which in turn to suppress the expression of Caspase-3.