Rat model for CKD

Rats underwent 5/6 nephrectomy for induction of CKD as previously established in our laboratory.[16] Briefly, 5/6 nephrectomy was performed in two consecutive surgeries: two-thirds of the left kidney was removed followed by removal of the right kidney a week later. Control animals underwent abdominal opening only (Sham). Animals were kept for eight months. Two animals died during the echocardiography procedure: one from each group. In addition, during the long-term CKD period, one rat was euthanized due to loss of more than 15% of its body weight and 4 other rats died in the late experimental period (after four to seven months); therefore, the final total number of animals was 15 in CKD and 17 in sham groups. Urine samples were collected for 24-hour time periods, during which the animals were kept in metabolic cages (Lavotal, Italy) where they were allowed to eat and drink ad libitum. Blood and urine samples were collected in order to determine plasma levels of AngII, pro- and anti-inflammatory cytokines, Blood Urea Nitrogen (BUN) and to calculate creatinine clearance (Ccr).[16] At time of necropsy, heart and kidney weights were documented by weighing the organs immediately after excision. Tissues were kept at -80°C for further analysis.