Tlx1 (Hox11) related gene expression profile after intra-splenic islet transplantation in mice

From the past reports, we hypothesized that spleen is an ideal site for inducing regeneration of transplanted islets, and leading to reduce the required number of islets for ameliorating the hyperglycemia of diabetic recipients in mice. In order to confirm this hypothesis, we performed 25 islets transplantation into spleen (SP25); it was not enough number to ameliorate the hyperglycemia of recipient mice, with 100 islets transplantation into beneath the kidney capsule (KC100) to maintain recipients' blood glucose normoglycemic temporary. All recipient mice (n=11) became normoglycemic after receiving SP25 with KC100. On 240 days after transplantation, we performed nephrectomy for removing islet grafts in the kidney. After nephrectomy, 8 of 11 mice remained normoglycemic, and 3 of 11 mice' non-fasting blood glucose levels were maintained around 300 mg/dL. On 290 days after transplantation (50 days after nephrectomy), all recipient mice received splenectomy to remove islet grafts in the spleen. All mice became hyperglycemic after splenectomy, indicating that intra-splenic islet grafts maintained the blood glucose levels of diabetic recipient mice. In order to investigate the gene expression associated with islets engraftment in the spleen, microarray studies were performed in comparison of the Tlx-1 (Hox11) related gene expression profiles of Sample 1, Sample 2 and Sample 3. Twenty-five islets and 100 islets were transplanted into spleen and beneath the kidney capsule of recipient mice, respectively (SP25+KC100). Then, spleen was harvested just after transplantation (Sample 1) or 2 days after transplantation (Sample 2). Furthermore, 100 days after receiving SP25+KC100, nephrectomy was performed for removing islet graft in the kidney, and those nephrectomized mice received splenectomy on 139 days after transplantation for harvesting the spleen sample of the recipient mice (Sample 3). Total RNA was prepared from these spleen.