Somatostatin(SST),named for its ability to inhibit pituitary growth hormone(GH)secretion,is involved in multiple physiological processes though somatostatin receptors(SSTRs).Both in vitro and in vivo studies have demo...Somatostatin(SST),named for its ability to inhibit pituitary growth hormone(GH)secretion,is involved in multiple physiological processes though somatostatin receptors(SSTRs).Both in vitro and in vivo studies have demonstrated that SSTR2 mediates GH inhibition by SST.However,whether a deficiency of SSTR2 promotes the somatic growth of fish is unclear.In this study,both sstr2a and sstr2b were predominantly expressed in the pars distalis of the pituitary gland,with sstr2a showing higher expression levels than sstr2b.Mutation of sstr2a was performed in tilapia using the CRISPR/Cas9 system.The sstr2a^(-/-)mutants exhibited a significant increase in body weight at 60,120,and 180 days post fertilization(dpf)when reared in mixed populations with wild type(WT)fish,being 43%heavier than WT fish at 180 dpf.The sstr2a^(-/-)mutants also demonstrated better growth than WT fish under the separate-tank culture condition,with higher body weight,length,height,and width,weight gain rate,and specific growth rate,as well as lower food intake and feed coefficient,but no difference in condition factor.Furthermore,among female and male sstr2a^(-/-)mutants and WT controls,the growth of male sstr2a^(-/-)mutants was the highest,followed by female sstr2a^(-/-)mutants,then WT males and WT females.No differences were observed between sstr2a^(-/-) mutants and WT fish in the mean area and number of muscle fibers per visual field under the microscope.However,there were fewer lipid droplets in the liver in sstr2a^(-/-) mutants than in WT fish.The deficiency of SSTR2a also led to elevated circulating GH and IGF-1 levels and up-regulated expression of GH/IGF axis genes.Overall,the first established sstr2a^(-/-) mutant line in fish not only holds significant potential to develop into a fast-growth strain of tilapia,but also provides an excellent model for understanding the regulation of growth and metabolism in teleosts.展开更多
目的探讨microRNA-31对脊髓损伤后胃肠动力因素的作用。方法将36只microRNA-31转基因小鼠和36只FVB小鼠分别设为对照组和模型组,用Impactor M-Ⅲ脊髓撞击器建立小鼠脊髓损伤模型。用BBB运动功能评分评估小鼠下肢的恢复情况。HE染色观察...目的探讨microRNA-31对脊髓损伤后胃肠动力因素的作用。方法将36只microRNA-31转基因小鼠和36只FVB小鼠分别设为对照组和模型组,用Impactor M-Ⅲ脊髓撞击器建立小鼠脊髓损伤模型。用BBB运动功能评分评估小鼠下肢的恢复情况。HE染色观察脊髓组织的变化。用Real-time PCR法检测生长抑素受体(SSTR2)mRNA的表达,用免疫荧光法检测一氧化氮合酶(iNOS)蛋白和SSTR2蛋白的表达。结果造模后第3天、第7天和第14天,脊髓组织破坏、坏死、空泡形成,胶原纤维明显增加。造模后第14天,FVB模型组与对照组比较,SSTR2 m RNA的表达明显升高(P<0.05),iNOS蛋白和SSTR2蛋白的表达量明显升高;microRNA-31转基因小鼠模型组与对照组比较,SSTR2 mRNA的表达明显升高(P<0.05),iNOS蛋白和SSTR2蛋白的表达量明显升高;microRNA-31转基因小鼠模型组与FVB模型组比较,SSTR2 m RNA的表达明显降低(P<0.05),iNOS蛋白和SSTR2蛋白的表达量明显降低。结论脊髓损伤后胃肠动力障碍的发生可能与SSTR2 m RNA的表达上调、SSTR2蛋白和i NOS蛋白的表达增高有关。高表达的microRNA-31可能与脊髓损伤后胃肠动力障碍的恢复有关。展开更多
基金funded by the National Key Research and Development Program of China(2022YFD1201600)China Agriculture Research System of MOF and MARA(CARS-46)+1 种基金National Natural Science Foundation of China(32473156,32373106 and 32172953)Chongqing Fishery Technology Innovation Union(CQFTIU202501-7).
文摘Somatostatin(SST),named for its ability to inhibit pituitary growth hormone(GH)secretion,is involved in multiple physiological processes though somatostatin receptors(SSTRs).Both in vitro and in vivo studies have demonstrated that SSTR2 mediates GH inhibition by SST.However,whether a deficiency of SSTR2 promotes the somatic growth of fish is unclear.In this study,both sstr2a and sstr2b were predominantly expressed in the pars distalis of the pituitary gland,with sstr2a showing higher expression levels than sstr2b.Mutation of sstr2a was performed in tilapia using the CRISPR/Cas9 system.The sstr2a^(-/-)mutants exhibited a significant increase in body weight at 60,120,and 180 days post fertilization(dpf)when reared in mixed populations with wild type(WT)fish,being 43%heavier than WT fish at 180 dpf.The sstr2a^(-/-)mutants also demonstrated better growth than WT fish under the separate-tank culture condition,with higher body weight,length,height,and width,weight gain rate,and specific growth rate,as well as lower food intake and feed coefficient,but no difference in condition factor.Furthermore,among female and male sstr2a^(-/-)mutants and WT controls,the growth of male sstr2a^(-/-)mutants was the highest,followed by female sstr2a^(-/-)mutants,then WT males and WT females.No differences were observed between sstr2a^(-/-) mutants and WT fish in the mean area and number of muscle fibers per visual field under the microscope.However,there were fewer lipid droplets in the liver in sstr2a^(-/-) mutants than in WT fish.The deficiency of SSTR2a also led to elevated circulating GH and IGF-1 levels and up-regulated expression of GH/IGF axis genes.Overall,the first established sstr2a^(-/-) mutant line in fish not only holds significant potential to develop into a fast-growth strain of tilapia,but also provides an excellent model for understanding the regulation of growth and metabolism in teleosts.
文摘目的探讨microRNA-31对脊髓损伤后胃肠动力因素的作用。方法将36只microRNA-31转基因小鼠和36只FVB小鼠分别设为对照组和模型组,用Impactor M-Ⅲ脊髓撞击器建立小鼠脊髓损伤模型。用BBB运动功能评分评估小鼠下肢的恢复情况。HE染色观察脊髓组织的变化。用Real-time PCR法检测生长抑素受体(SSTR2)mRNA的表达,用免疫荧光法检测一氧化氮合酶(iNOS)蛋白和SSTR2蛋白的表达。结果造模后第3天、第7天和第14天,脊髓组织破坏、坏死、空泡形成,胶原纤维明显增加。造模后第14天,FVB模型组与对照组比较,SSTR2 m RNA的表达明显升高(P<0.05),iNOS蛋白和SSTR2蛋白的表达量明显升高;microRNA-31转基因小鼠模型组与对照组比较,SSTR2 mRNA的表达明显升高(P<0.05),iNOS蛋白和SSTR2蛋白的表达量明显升高;microRNA-31转基因小鼠模型组与FVB模型组比较,SSTR2 m RNA的表达明显降低(P<0.05),iNOS蛋白和SSTR2蛋白的表达量明显降低。结论脊髓损伤后胃肠动力障碍的发生可能与SSTR2 m RNA的表达上调、SSTR2蛋白和i NOS蛋白的表达增高有关。高表达的microRNA-31可能与脊髓损伤后胃肠动力障碍的恢复有关。
