Study of the therapeutic effects of administration of recombinant DNA molecules containing the target gene of human preproinsulin on models of streptozotocininduced diabetes in mice and rats

Abstract

Aim is to study the therapeutic effects of gene therapy for type 1 diabetes mellitus by the administration of recombinant DNA molecules containing the target gene of  human preproinsulin (DNA-TGHPPI) to experimental animals. Methods. The effect of administration of recombinant DNA molecules containing the target gene of  human preproinsulin (DNA-TGHPPI) into the liver parenchyma of C57BL/6j mice and Wistar rats with different duration (two and five weeks) of streptozotocin-induced  diabetes (STD) was studied. Blood glucose was tested using glucose oxidase method, serum insulin and C-peptide — by immunoenzymic method. Results.  The studies of the effect of administration of different concentrations of DNA-TGHPPI into rats (25 to 60 mcg) and mice (10 to 15 mcg) liver parenchyma  allowed to determine the optimal doses of DNA that led to a significant and prolonged (more than two months) decrease in hyperglycemia in diabetic animals. A  decrease in glycemia in mice was noted two weeks after a single injection of DNA-TSHPPI, and this decrease lasted 5-9 weeks. The most marked decrease in glycemia  after a single DNA-TGHPPI injection was established in rats with a short (twoweeks) STD and lower baseline glycemia. Experiments on intact rats  suggest a more  prolonged decrease in blood glucose after a single injection of preproinsulin gene (for 52 weeks). The administration of DNA-TSHPPI to rats with two-weeks STD  results in the appearance of significant levels of human insulin in the animal blood within a specified time after a single procedure of gene therapy. A strong positive  correlation was found between the indicators of human insulin and C-peptide levels in blood serum of rats with STD at different periods after DNA-TSHPPI  administration. Conclusions. A study of the conditions of effective expression of preproinsulin gene in C57BL/6j mice and Wistar rats shows that expression and  duration of the decrease in glycemia depend on streptozotocin diabetes duration, baseline glycemia in animals with STD and DNA concentration in transfection preparation.