Inflammatory oxidative stress in umbilical hernia repair with and without opening of the peritoneum in the calf: malondialdehyde and plasma serotonin concentration as biomarkers

Umbilical hernia is a very common congenital surgical pathology in calves. Surgery causes inflammatory oxidative stress, which can lead to post-surgical pathologies. Balanced anesthesia plays a fundamental role in the prevention of the same. The aim of the study was to compare the inflammatory oxidative stress induced by two surgical techniques for umbilical hernia repair in calves. This study was approved by the Institutional Ethics Committee for Animal Welfare of the University of Messina, protocol number 027/2018. Fifty-nine calves, between approximately 2 months of age and 70 ± 30 kg in weight. They were divided in group A, subjects operated with the open technique, and group B, subjects operated with the closed technique. Subjects were sedated using romifidine 0.08 mg/kg (IM) and local butorphanol 0.02 mg/kg, Physiological Parameters, heart rate (HR, beats/min), non-invasive systolic (SAP), mean (MAP) and diastolic (DAP) arterial blood pressure (mmHg) and haemoglobin oxygen saturation (SPO2), were measured using multiparameter monitor Instrument. Respiratory rate (RR) was assess thoracic excursions per minute count. Body temperature, was measured using a digital thermometer. The parameters were recorded at T0; basal values and from T1 to T8 intraoperatively. Rescue analgesia was administered, 2 mg/kg lidocaine 2%, only when physiological parameters (HR, RR, SAP) increased by 20% than T0. To assess sedation a descriptive scale was used, with scores from 0 to 3: 0–animal awake; 3–deep sedation. Post-operative pain assessment was performed using UNESP-Botucatu UCPS-IV, no pain (score 0) to severe pain (score 10); the post-operative pain score ≥4 was cut-off point for administered rescue analgesia; 3.3 mg/kg flunixin meglumine IV. Inflammatory oxidative stress was assess using determination of serum Malondialdehyde (MDA) and plasma serotonine (5-HT) concentration. Determination of MDA levels were performed using Merck (Darmstadt, Germany) and Fluka (Buchs, Switzerland) reagents. Plasma 5-HT concentration was evaluated using ELISA Assay kit (BioVision incorporated, Milpitas, CA, USA). Malondialdehyde and 5-HT levels were determinate at baseline T0 and at 36 hours after the surgery T9. Physiological parameters were within range for calf. No intraoperatively rescue analgesia was required. Postoperatively pain score was lower in group C than group A P=0.000. Request of postoperatively rescue analgesia was 30 minutes after returning to the standing position in group A and 40 minutes after in group C P=0.000. Malondialdehyde concentrations showed a significant increase between baseline and postoperative (T0-T9) in both groups. The comparison between groups showed a higher increase in MDA concentration in group A than group C with P=0.000. 5-HT concentrations showed a significant reduction in the postoperative period from baseline in group A, and a moderately significant increase in group C P=0.020. Surgery causes inflammatory oxidative stress demonstrated in the present study by the increase in MDA concentration and by the variation in 5HT concentration, whose release varies from case to case (1). In the present study, group C showed a lower postsurgical inflammatory stress than group A. Therefore the surgical technique of umbilical hernia repair without opening the peritoneum proved to be less invasive.