[Effects of leukocyte depletion filter on canine kidney during cardiopulmonary bypass]

To explore the effect of a reforming leukocyte depletion filter (LDF-1) on the functional and pathologic changes of canine kidney during cardiopulmonary bypass (CPB).

Twelve Mongolian dogs were randomly allocated into a control group (no LDF-1, n = 6) or a leukocyte-depleted filter group (LDF-1 placed in venous line, n = 6). CPB of the dogs anestheitized with sodium pentobarbitone at 25 mg/kg was set up. After 10 min of CPB, aorta was clamped and St. Thomas cardioplegic solution at 20 mg/kg was immediately injected into the root of aorta. The aortic cross-clamp was released and CPB was closed at 70 min. Dogs were observed for 2 h after weaning from CPB. LDF-1 was opened at 2 min and stoped at 7 min during initially running CPB in the LDF-1 group. Circulating leukocytes, plasma L-selectin, and plasma IL-8 were respectively counted before CPB, at 10 minutes, 40 min, and 75 min during CPB, the end of CPB, and 2 h after CPB. The urine analysis and renal pathology, which were obtained before CPB and 2 h after CPB, were observed.

The number of leukocytes significantly decreased by 55% - 68% in the LDF-1 group compared with the baseline during CPB. The value at 10 min of CPB in the LDF-1 group was lower than that in the control group (P < 0.05). Plasma levels of L-selectin and IL-8 obviously increased in the 2 groups compared with the baseline during CPB, but both levels at 2 h after CPB in the LDF-1 group were lower than those in the control group (P <0. 05). No statistic difference was found in plasma levels of urea and creatinine, but hematuria was observed in the 2 groups at 2 hours after CPB. The pathologic changes of kidney, which was mainly renal tubule swelling accompanied partly with vacuolar degeneration, were similar under the light microscope in the 2 groups at 2 h after CPB. Obvious glomerular damage was not found.

LDF-1 can effectively decrease leukocyte counts and the inflammatory reaction, but it can not bring about excellent protective effect on kidney during CPB when used alone. Attention to should be paid the renal protection in the postoperative CPB.