【Abstract】 Objective The aim of the study was to investigate the effect of small doses of nitroglycerin (NTG) on cardio-protection in diabetic patients undergoing laparoscopic cholecystectomy, evaluated by changes of cardiac troponin I (cTnI) and its correlation with alteration of plasma CGRP, perioperatively. Methods Twenty diabetic patients undergoing elective laparoscopic cholecystectomy were enrolled and randomized into two groups, NTG treatment group (as group A, n=9) and the non-treatment group ( as group B, n=11), according to whether or not treated with nitroglycerin. The patients in treatment group received intravenous infusion of nitroglycerin at rate of 0.1~0.25 μg/kg/min throughout the anesthesia, while the patients in group B were given normal saline instead. And the blood pressures, heart rate, electrocardiogram and pulse oxygen saturation were routinely monitored. Comparisons were made for the heart rate(HR) and the mean arterial pressure (MAP) at 30min before start of operation, immediately at intubation, extubating and 30min after operation (described as T1, T2, T3 and T4, respectively). Blood samples were collected for evaluation of CGRP at T1, T4 and 24 hours after operation (T5) and for cTnI at T1 and T5 only. Results Compared to that at T1, the slight but significant decreases of MAP at T2 in group A and at T4 in group B were observed (all p < 0.05). However, there was no significant change in HR in the two groups. Lower plasma CGRP levels of were detected in Group B, at T4 and T5, when compared to that of T1 (T1: 16.4±3.5 pg/ml, vs T4: 14.1±3.6pg/ml and T5: 13.2±2.4 pg/ml, all p < 0.05), while no difference was observed in group A. Interestingly, greater level of cTnI was seen in the patients of group B 24 hours post operation, compared to that at T1 (3.55±0.28 ng/ml vs 3.88±0.30 ng/ml, p < 0.05). No significant change in cTnI was detected in the patients of group A. In addition, a significant drop in MAP was observed at T3 in the patients of group A, compared to that in group B. No other significant difference was seen when comparing the parameters between the two groups. Conclusion The results of this pilot study indicate that administration of small doses of nitroglycerin may secure a homeostasis of plasma cTnI and CGRP in diabetic patients underwent laparoscopic cholecystectomy, which may play a role in cardio-protection perioperatively.