To explore the protective effect of sulforaphane (SFN) on septic myocardial injury (SMI) rats.

Sixty male wistar rats were randomly divided into a sham operation group, an SMI group, and an SFN group, with 20 rats in each group. Rats in the SMI group were prepared by cecum ligation and puncture (CLP), rats in the sham operation group were only exposed to the cecum by laparotomy, and rats in the SFN group were injected with 5 mg/kg SFN infusion 6 hours after CLP. Ten rats were selected from each group and observed for 48 hours after the operation; the mortality of rats at each time point was recorded. The hemodynamics of the remaining rats in each group were monitored by intraventricular catheterization through the right common carotid artery 24 hours after the operation, including heart rate, mean arterial pressure (MAP), left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP), maximal rate of left ventricular pressure rise during systole (+dp/dtmax), and maximum negative rate of left ventricular pressure decline (-dp/dtmax). The serum levels of cardiac troponin I (cTnI) and lactate dehydrogenase (LDH) and the myocardial tissue levels of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), nitric oxide (NO) and reactive oxygen species (ROS) were measured by the enzyme-linked immunosorbent assay (ELISA). The protein expression levels of Toll-like receptor 4 (TLR4) and nuclear factor E2-related factor 2 (Nrf2) in myocardial tissue were determined by western-blotting.

There was a statistically significant difference in the survival time among the three groups (χ² = 23.720, P < 0.001), but there was no statistically significant difference in the survival time between the SMI group and the SFN group (P = 0.084). The expression levels of heart rate, LVSP, LVEDP, +dp/dtmax, -dp/dtmax, cTnI, LDH, TNF-α, IL-1β, NO, and ROS among the three groups showed statistically significant differences (F = 54.901, 95.190, 94.335, 111.104, 76.477, 1 263.532, 57.782, 1 130.698, 338.950, 155.727, 342.914; all P < 0.001). Compared with the sham operation group, the heart rate, LVSP, +dp/dtmax, and -dp/dtmax in the SMI group and SFN group were significantly decreased, and the above indicators in the SMI group were lowest (all P < 0.05); the levels of LVEDP, cTnI, LDH, TNF-α, IL-1β, NO, and ROS in both the SMI group and the SFN group were significantly increased, and the above indicators in the SMI group were highest (all P < 0.05). Western-blotting showed that there were statistically significant differences in the expression levels of Nrf2 and TLR4 in myocardial tissues among the three groups (F = 26.294, 32.667; both P < 0.001). Compared with the SMI group, the expression of Nrf2 in the SFN group was significantly increased, and the expression of TLR4 was significantly decreased (both P < 0.05).

SFN can alleviate septic myocardial inflammation and oxidative stress in rats and has a certain protective effect on SMI. Its mechanism of action may be related to the inhibition of TLR4 and the enhancement of the Nrf2 signaling pathway.