Generation Of Uricase-Deficient Rats

Objectives:The uricase-deficient rats were constructed and identified by their biological features,enzyme activity,protein and mRNA.The study wanted to provide a stable and economical model animal for the study of hyperuricemia and gout and also for drug developmentMethods:1.Generation of uricase-deficient rats:uricase-deficient rats were obtained by couples of Uox+/-Sprauge-Dowley(SD)rats.The number of their offspring,weight,male-female ratio,life span,and survival rate were evaluated and compared with those of wild-type rats.Phenotype identification of uricase-deficient rats:uric acid in serum and tissues,serum glucose content,blood fat indexes,and renal function were detected in uricase-deficient rats and compared with that of wild-type rats.2.Molecular identification of uricase-deficient rats:uricase activity was determined in uricase deficient rats;identification of uricase gene in uricase deficient rats by exon sequencing and high-throughput sequencing.The expression of xanthine dehydrogenase(Xdh)and adenosine deaminase(Ada)in uricase-deficient rats was also determined by high-throughput sequencing.Results:1.The uricase-deficient rats have been bred for 5 generations.There was no differences of male-female ratio,life span,and survival rate in uricase-deficient rats between that in wild-type rats.The body weight of uricase-deficient rat at 6th week is lighter than that of wild-type rat.2.The serum uric acid in uricase-deficient rats was significantly higher than that in wild-type rats.The uric acid in the ileum,pancreas,lung,stomach and adrenal gland was significantly also higher than that in wild-type rats,and there was no significant difference in uric acid among other tissues.Serum glucose in uricase-deficient rats was not different from that in wild-type rats as expected.There was no significant different blood fat between the uricase-deficient rats and the wild-type rats either.However,there was a mild injury in the kidney.3.Uricase activity in serum and liver homogenate was detected in the uricase-deficient rats;exon sequencing showed that at least exon 3 of uricase gene was deleted in the uricase-deficient rats;high-throughput sequencing further showed exons 2 to 4 of the uricase gene were deleted,and uricase mRNA of the uricase-deficient rats were much shorter than that of wild-type rats;and expression profile sequencing showed no difference in xanthine dehydrogenase and adenosine deaminase expression between uircase-deficient rats and wild-type rats.Conclusions:Uricase-deficient rats were successfully generated,and their serum uric acid is higher than that of wild-type rats.The animal showed no uricase activity with similar survival rate to wild-type rat.The animal is suitable for the study of hyperuricemia and gout.