Restrictive hypertonic saline resuscitation is associated with less intestinal injury after hemorrhagic shock in rats and with coordinated changes in MALAT1, miR-145-5p, and BNIP3 expression.

Background: Intestinal ischemia-reperfusion contributes to barrier failure and secondary organ injury after hemorrhagic shock. It is not known whether restrictive hypertonic saline resuscitation alters the resulting intestinal injury or the accompanying non-coding RNA response.

Methods: One hundred male Sprague-Dawley rats were allocated to normal control, hemorrhagic shock, conventional 0.9% saline resuscitation (CFR), restrictive 7.5% hypertonic saline resuscitation (RFR), or superior mesenteric artery ischemia-reperfusion control groups. Hemorrhagic shock was induced by controlled blood withdrawal to maintain mean arterial pressure (MAP) at 35-40 mmHg for 60 min. CFR targeted an MAP of approximately 80 mmHg, whereas RFR targeted an MAP of approximately 60 mmHg. Three-hour survival was recorded. Coagulation, serum IL-6 and TNF-α, qRT-PCR, Western blotting, H&E staining, and TUNEL were assessed in assay-specific subsets. Public GEO datasets were analyzed for exploratory transcriptomic context.

Results: Three-hour survival was 75% in RFR and 60% in CFR (two-sided Fisher exact test, P = 0.501). In the coagulation cohort, prothrombin time (PT) and thrombin time (TT) were shorter in RFR than in CFR after Dunn-Holm adjustment; no differences were observed for activated partial thromboplastin time (APTT), international normalized ratio (INR), and prothrombin activity (PA). RFR had lower serum IL-6 and TNF-α, better-preserved ileal morphology, and lower TUNEL positivity in representative fields than CFR. MALAT1 was lower, while miR-145-5p and Bnip3/BNIP3 were higher in RFR. Exploratory analyses of public datasets confirmed that Malat1 and Bnip3 are expressed in the intestinal cell populations relevant to ischemia-reperfusion injury.

Conclusion: Under the present experimental conditions, restrictive hypertonic saline resuscitation was associated with a less severe acute intestinal injury phenotype than conventional isotonic resuscitation. The coordinated changes in MALAT1, miR-145-5p, and BNIP3 do not establish a linear regulatory axis and require functional validation.