| Part I Purpose:To explore the relationship between the growth and development of idiopathic short stature(ISS)and nanomaterial exposure in environment.Method:The ISS group was conducted among 94 diagnosed ISS children and the control group was conducted 56 health children from January 2021 to January 2022,who were chosen from the Second Affiliated Hospital of Nanchang University.The age range of ISS group was from 4 years old and 2 months to 14 years old and 11 months,including47 males and 47 females.The age range of control group was from 3 years old and 9months to 15 years old and 4 months,including 23 males and 33 females.We collected information about children’s possible exposure to nanomaterials in their daily life by consulting relevant literature,then developed a questionnaire.We distributed questionnaires to parents and collected relevant medical history information.The data was analyzed by the SPSS 25.0 software.Result:1.Compared to the control group,there were no statistical significance in the age,body weight,sex,the ways of birth and the feeding modalities(P>0.05).2.The results of univariate logistic regression are as follows:(1)The use of adult toothbrush,plush toys,water purifier,dental gum or pacifier,straw cup and living near factories or streets are the risk factors of ISS in children(P<0.05).(2)These factors were not statistically related to the occurrence of ISS:eating sweets,eating seafood and surimi products,using toothpaste before 5 years old,using electronic products frequently,there are rubber toys or rubber covers in the living environment,using humidifier,using sunscreen or cream and other skin care products,using children’s furniture,visiting Stomatology Department(P>0.05).3.The results of multivariate logistic regression analysis of six statistically significant factors are as follows:(1)Children using water purifiers are 6.461 times(95%CI 2.547-16.391)more likely to develop ISS than those not using them(P<0.001).(2)Children using teethers or pacifiers are 3.332 times(95%CI 1.430-7.766)more likely to develop ISS than those not using them(P<0.01).(3)Children using teethers or pacifiers are 3.910 times(95%CI 1.595-9.589)more likely to develop ISS than those not using them(P<0.01).(4)Children living in factories or streets are 2.646 times(95%CI 1.039-6.740)more likely to develop ISS than those living in such areas(P<0.05).(5)There was no significant difference between the use of adult toothbrush and plush toys and ISS(P>0.05).Conclusion:The use of water purifier,pacifier,teether and sippy cup is the risk of ISS.The above products conduct nanomaterials.We should use products of qualified quality in our daily lives.Living near a factory or street is also a risk for ISS.Such environments are prone to nanoparticles.Children should avoid long-term exposure to polluted environments around factories or streets.Part IIPurpose: To evaluate effects of different crystal forms titanium dioxide nanoparticles(Ti O2 NPs)on the bone tissue in young rats,and explore the mechanism.Method: Fifteen 3-week-old male young rats were randomly divided into three groups.The control group was orally administered with the same dose of ultrapure water.The anatase Ti O2 NPs group was were orally administered anatase Ti O2 NPs.The rutile Ti O2 NPs group was were orally administered rutile Ti O2 NPs.All SD rats were orally administered for 28 days.Body length,body weight and tibia length were measured to evaluate the growth of rats.The levels of alanine aminotransferase(ALT),aspartate aminotransferase(AST)and alkaline phosphatase(ALP)were measured by a biochemical analyzer and insulin-like growth factor-1(IGF-1)level were also measured by ELISA.The bone damage was evaluated by Micro-computed tomography(Micro-CT).Immunohistochemistry was used to access the expression of osteoprotegerin(OPG)、receptor activator of nuclear factor-κB ligand(RANKL)and cathepsin K(CTSK).Result: 1.Percent weight growth,body length,and tibia length all decreased in the groups exposed to both anatase and rutile Ti O2 NPs compared with those in the control group(P>0.05).No significant differences between groups were observed in terms of body mass index(P>0.05).2.By contrast,significant differences between the group exposed to rutile Ti O2 NPs and other groups were observed in terms of levels of ALT(P<0.05)and AST(P<0.01).And the levels of ALT(P<0.05)and AST(P<0.01)in rutile Ti O2 NPs group were highly than anatase Ti O2 NPs group.No significant differences between each group were found in terms of levels of ALP(P>0.05).IGF-1 levels in the serum decreased in the group exposed to rutile Ti O2 NPs(P<0.01).3.Microcomputed tomography(Micro-CT)of the tibia demonstrated that the bone of anatase Ti O2 NPs group and rutile Ti O2 NPs group had osteoporosis.Micro-CT data supported the same result.BMD and BS decreased in the anatase Ti O2 NPs group and rutile Ti O2 NPs group(P<0.05).Connectivity density(Conn.Dn)decreased in the group exposed to anatase Ti O2 NPs(P<0.05).Conn.Dn was lower in the group exposed to rutile Ti O2 NPs than in the control group(P<0.01).In the group exposed to rutile Ti O2 NPs,BV/TV and Tb.N decreased,whereas SMI increased(P<0.05).In the anatase Ti O2 NPs group and rutile Ti O2 NPs group,BS/BV,Tb.Pf,and Tb.Sp increased,whereas BS/TV and Tb.Th decreased(P>0.05).There was no significant difference in T.Ar,T.Pm,B.Ar,B.Pm,B.Ar/T.Ar and Ct.Th(P>0.05).4.In the anatase Ti O2 NPs group and rutile Ti O2 NPs group,the expression of OPG was decreased,while the expression of CTSK was increased(P>0.05).Furthermore,expression of RANKL was higher in the group exposed to anatase Ti O2 NPs than in the control group(P<0.05).RANKL expression was significantly higher in the group exposed to rutile Ti O2 NPs than in the control group(P<0.001).The ratio of OPG/RANKL significantly decreased in the group exposed to rutile Ti O2 NPs(P<0.05).Conclusion: This study demonstrated that Ti O2 NPs can damage bones via the IGF-1/OPG/ RANKL/CTSK pathway in young rats.Furthermore,rutile Ti O2 NPs damaged the bones more seriously than anatase Ti O2 NPs. |
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