The Preventive Effect of Ulinastatin on Blood–Brain Barrier Dysfunction in Rats with Postoperative Cognitive Dysfunction After General Anaesthesia with Isoflurane

This study evaluated the effect of ulinastatin on blood-brain barrier (BBB) dysfunction in rats with postoperative cognitive dysfunction (POCD) following general anaesthesia with isoflurane. Specifically, we examined BBB permeability and the expression of tissue inhibitor of matrix metalloproteinase-1 (TIMP-1). Rats in the ulinastatin group received the drug intraperitoneally (50,000 U/mL), while controls received normal saline (1 mL) administered before general anaesthesia. Isoflurane (1.5% volume) anaesthesia was induced for 2 h. Cognitive function was assessed using the Y-maze test. Two days after anaesthesia, BBB permeability was measured using Evans blue, and TIMP-1 expression was evaluated. Both groups experienced cognitive decline following anaesthesia. However, the ulinastatin group showed a more limited decrease (control group, 64.2 ± 19.3 → 30.2 ± 16.2, <i>p</i> = 0.008; ulinastatin group, 70.0 ± 15.7 → 66.5 ± 12.0, <i>p</i> = 0.67). The ulinastatin group showed a significantly lower permeability of the BBB (0.034 ± 0.003 µg/g in control group vs. 0.005 ± 0.002 µg/g in ulinastatin group, <i>p</i> = 0.0001), and also showed a significantly higher value of TIMP-1 expression (5.81 ± 1.94% in control group vs. 13.97 ± 2.59% in ulinastatin group, <i>p</i> = 0.0001). Administration of ulinastatin before general anaesthesia mitigated cognitive decline in rats with POCD, likely through the prevention of BBB dysfunction, as evidenced by the lower BBB permeability and increased TIMP-1 expression.