| Diabetes is a complex,multifactorial and polygenic disease characterized by hyperglycemia caused by deficiency of insulin secretion or insulin resistance.Globally as of 2010,an estimated 285 million peoples have type 2 diabetes(T2DM)making of about 90%of all diabetes cases.The mechanism of T2DM is still not fully understood.Animal models of T2DM provide the opportunity to investigate the pathophysiology as well as develop new drug and evaluate potential strategies to treatment and prevention of the disease and related complications.More and more mini-pig models of T2DM were used in T2DM research since human and pigs appear to have very similar gastrointestinal structure and function,pancreas morphology and overall metabolic status.The SNPs polymorphism of PPARγ-2,TNF-a,Leptin and Nor-1 genes were surveyed in the present study and their relationship with T2DM risk in Guangxi Bama mini-pigs was evaluated with attempt to screen the genetic markers which can be used in the breeding of T2DM high-risk and T2DM low-risk mini-pig strains.The SNP 19813A/G in exon2 of PPARγ-2 gene was determined by PCR-RFLP in 86 Guangxi Bama mini-pigs.Eighteen pigs(♀10,(?)8)with 19813AA genotypes and 28 pigs(♀14,(?)14)with 19813AG genotypes were then selected and fed with a high-fat and high-sugar diet for 210d and their blood Glu,T-Cho,TG,HDLC,LDLC and INS concentrations were measured from 0 to 210d in 30d intervals.The SNPs of.other T2DM related-genes including TNF-a,Leptin and Nor-1 were also determined in the pigs fed with the high-fat and high-sugar diet.The results of the experiment were showed as follows:(1)The serum Glu and INS levels of pig increased with the increasing period of feeding until 120d and decreased to the lowest level on d 150 of the experiment.After fed with the experiment diet for 210d,43.5%of pigs(20/46)were identified to be T2DM cases.The incidence risk of T2DM was higher in male than in female(54.5%v.s 33.3%).(2).The incidence rate of T2DM was 46.4%(13/28)and 38.9%(7/18)in pig carried with PPARy-2 19813AG and19813AA genotype,respectively.Of the 20 T2DM pigs,65.0%(13/20)of animals were indentified to be 19813 AG genotype and 35%(7/20)were 19813AA genotype.There were 26 pigs could not be identified to be T2DM,of which the percentage of 19813AA and AG genotype were 57.7%and 42.3%respectively.The Glu level on d 210 of the experiment was significantly higher in 19813AG genotype than in 19813AA genotype(P<0.05).These results indicated that SNP 19813A/G was related to the incidence risk of T2DM in Guangxi Bama mini-pig.(3)Several mutations were found in 2 T2DM-related genes,i.e.209C→T and 233C→T in exon 1 and 1827T→in exon3 of TNF-α gene,and 881G→A in exonl and 3390T→Cand 3638G→T in exon2 of Leptin gene.No SNPs was detected in exon 3,4,5,6 and 7 of Nor-1 gene.All mutations found were synomymous mutation except for the missence mutation of 881G→A in Leptin exon1 which made the Valine changed into isoleucine.(4)The distribution of Leptin SNP 881G/A in the population showed significant fitness to Hardy Wenbarg balance.The distribution of 881AA(6),881AG(25)and 881GG(15)conformed to Mendelian segregation of 1:2:1(χ2=3.86,P>0.1).The correlation analysis indicated that the T2DM incidence rate in 881AA,881AG,881GG genotype are 16.7%(1/6),64.0%(16/25)and 20.0%(3/15),respectively.The genotype frequency of 881AA,881AG,881GG were 0.05,0.8 and 0.15 in T2DM group and 0.192,0.346 and 0.462 in NGT(normal animal)group,respectively,which showed a significant difference in genotype frequency between the T2DM group and NGT group(P=0.0091).The serum Glu level was significant higher in 881 AG genotype than in other two genotypes on d 180 of the experiment(P<0.05).It was seem that animal with 881 AG genotype had higher T2DM risk.5.The correlation analysis of combining PPARy-2 19813A/G(A1A1,A,G,)with Leptin exonl 881A/GC A2A2,A2G2,G2G2)genotype showed that the T2DM incidence rate in A1G1A2G2 genotype was up to 73.3%(11/15),which was higher than that in PPARy-2 19813AG(46.4%)and Leptin 881 AG(64%)genotype.The fasting blood-Glu level of A1G1A2G2 genotype was higher than A1A1A2G2,A1A1G2G2,A1G1A2A2 and A1G1G2G2 genotype on d 210 of the experiment(P<0.05).It was shown that PPARγ-2 19813AG and Leptin 881AG has synergetic effect on T2DM risk,and the A1G1A2G2 genotype may be a genetic marker more closely related to the T2DM risk in Guangxi Bama mini-pig. |
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