The purpose of this study is to determine if intraventricular injection of human adipose tissue-derived stem cells (hADSC) are effective in treating streptozotocin (STZ)-induced diabetes mellitus (DM) in nude rats. Twenty-two adult, male nude rats (strain Crl:NIH-Fox1RNU) were used to induce diabetes using streptozotocin. A single, 150 mg/kg STZ was injected intraperitoneally. Severity of the induced diabetic state was assessed by daily monitoring of body weight, clinical signs, and blood glucose levels. C-peptide was assessed before ADSC injection (T0) and at 3, 5, and 21 days after ADSC injection. Eight rats (40%) developed DM within 24 h after STZ injection. Of the eight rats that developed DM, five were given 2 million freshly prepared ADSC intraventricularly under echocardiography guidance 10 days after STZ injection and three were only given sterile saline for comparison. Surviving rats were humanly sacrificed 21 days after ADSC injection. The average weight of diabetic rats decreased significantly after STZ injection. ADSC injection had no effect on the body weight of rats. Non-fasting serum glucose levels increased significantly in both groups. In diabetic rats, C-peptide decreased significantly before ADSC injection and seemed to return to normal 21 days after ADSC administration. Results of this preliminary study might suggest a beneficial effect of using hADSC for the treatment of STZ-induced diabetes in adult nude rats. [ABSTRACT FROM AUTHOR]