The Study Of Mode Of Life And Environmental Factors On Children’s Physical Growth And The Relevant Mechanisms

Part Ⅰ Purpose:To explore the relationship between idiopathic short stature(ISS)and lifestyle as well as environmental factors,providing basis for short stature prevention.Method:The ISS group was conducted 90 children with idiopathic short stature diagnosed in our hospital from January 2019 to January 2020,while the control group was matched 64 normal developmental children with same age and sex in the same period.The lifestyle and related environmental factors were investigated by questionnaire,such as the use of pacifier,feeding utensils materials,the existence of mildew,the existence of smokers,cooking methods,parents’ education level and other factors were investigated.The SPSS software was used to analyze the data difference in two groups Result:1.There was no significant difference in sex,age,birth mode,birth weight and feeding mode between the ISS group and the control group(P>0.05).2 The use of pacifying pacifier(OR=3.549,P=0.005)、plastic feeding utensils(OR=2.621,P=0.046)and family mildew(OR=3.313,P=0.006)were the risk factors of dwarfism.3 Father(OR=0.176,P=0.004)and mother’s education level(OR=0.164,P=0.004)were protective factors of dwarfism.Conclusion:Pacifiers,plastic feeding utensils and family mildew are risk factors for ISS.In the feeding process,pacifiers should be avoided as much as possible and appropriate feeding equipment should be selected,preventing mold in the family living environment which would reduce the incidence of ISS.Part ⅡPurpose: To evaluate the effects of different dosage znic oxide nanoparticles(Zn O NPs)on bone growth in young rats and explore the possible mechanisms of action.Methods: Three-week-old male rats were received different dosage of Zn O NPs(68,203,and 610 mg/kg/d)in experimental groups,and ultrapure water was used in the control group for 28 days,orally.Body length,weight,tibia length and body mass index(BMI)were measured to evaluate growth fettle.Serum aspartate aminotransferase(AST),alkaline phosphatase(ALP)and alanine aminotransferase(ALT)levels were measured to assess liver function.ELISA method was used to detect insulin-like growth factor(IGF-1).Micro-computed tomography(Micro-CT)was to assess the degree of tibia injury.Immunohistochemical was used to evaluated osteoprotegerin(OPG)and receptor activator of nuclear factor-κB ligand(RANKL)expression level.Results: 1.The 610 mg/kg Zn O NP group caused significant differences in weight growth rate,body length and tibia length compared with the control group(P<0.05).There were no significant differences in body mass index(BMI)(P>0.05).2.In experimental groups,the zinc concentration in liver and bone tissue increased significantly with increased Zn O NP dosage(P<0.05).Aspartate aminotransferase(AST)and alanine aminotransferase(ALT)levels were clearly increased in the 610 mg/kg Zn O NP group and didn’t existed significant differences compared with the control group(P>0.05),whereas alkaline phosphatase(ALP)existed significant differences in the 610 mg/kg Zn O NP group(P<0.05).3.Significant differences in insulin-like growth factor type 1(IGF-1)levels were observed in 203 and 610 mg/kg Zn O NP groups compared with the control group(P<0.05).4.Compared with the control group,micro-computed tomography(Micro-CT)of the tibia demonstrated signs of osteoporosis,such as decreased bone density,little trabecular bone structure and reduced cortical bone thickness in experimental groups.5.Micro-CT data further demonstrated significantly decreased bone mineral density(BMD),trabecular number(Tb.N)with increasing dosage of Zn O NPs in experimental groups.6.Compared with the control group,osteoprotegerin(OPG)expression and the ratio of OPG to receptor activator of nuclear factor-κB ligand(RANKL)were statistically lower in the 610 mg/kg Zn O NP group(P<0.05),whereas RANKL expression did not change significantly(P>0.05)Conclusion: We infer that Zn O NPs affect bone growth in young rats directly or indirectly by altering IGF-1 levels.Overall,the results indicate that Zn O NPs promote osteoclast activity and increase bone loss through the OPG/RANK/RANKL/IGF-1 pathway.