the effect of magnesium sulfate prevent lung injury related to pneumoperitoneum in ventilated rats

Although laparoscopy was initially regarded as a minimally invasive technique compared to open surgery, experimental and clinical studies in recent years have revealed that rises in intra-abdominal pressure (IAP) in association with degree of pneumoperitoneum (PP) established may lead to hypoperfusion, particularly in the abdominal organs. Following this hypoperfusion, oxidative injury may develop as a result of reperfusion with a fall in IAP following desufflation, and this may lead to injury in other organs, especially the lung. In addition, an increase in IAP may also contribute to increased injury in the lung with problems such as a decrease in pulmonary compliance, gas embolism, a fall in venous return and increased pulmonary injury causing an increase in absorption of CO2.Our purpose in this study was to investigate the effect of MgSO4 in preventing pulmonary injury after PP.Following approval from the experimental animals ethics committee, 18 female Sprague-Dawley rats (weight 240-280 g) were divided into three groups. Tracheotomy was performed under xylazine and ketamine anesthesia and all rats were attached to a mechanical ventilator. In Group 1 (n=6), rats were ventilated only, and no PP was established. In Group 2 (n=6), PP was established for 60 min under 12 mmhg pressure, while in Group 3 (n=6) 90 mg/kg MgSO4 was administered İP 30 min before 60-min PP at 12 mmHg. Blood and lung specimens from groups 2 and 3 were taken 30 min after abdominal desufflation following 60-min PP, and from Group 1 after 90-min ventilation. Plasma ischemia modified albumin (IMA) and malondialdehyde (MDA), and MDA in lung tissue were measured. Lung tissue was examined histopathologically.There was no significant difference among the groups in terms of weight. Plasma IMA levels were significantly higher in Group 2 compared to the other groups. Plasma IMA levels in Group 3, administered MgSO4, decreased significantly compared to the PP group. No significant change was observed in plasma and tissue MDA levels. Various significant reperfusion injury-related changes were observed at histopathological examination in Group 2. Widespread inter- and intra-alveolar hemorrhage, vascular congestion and alveolar edema were present in the PP group (Group 2) preparates. Peribronchial inflammatory cell infiltration and pronounced degeneration in alveolar architecture were observed. Alveolar hemorrhage was significantly lower in the preparates containing tissue sections from the magnesium sulfate group (Group 3) compared to the PP group. Alveolar architecture was close to normal. Vascular congestion was moderate, and the alveolar edema seen in the PP group was not observed.In conclusion, we determined that IR-related ınjury developing after PP causes injury in the lung. At histopathological examination of lung tissue we demonstrated that magnesium sulfate significantly prevents IR-related injury. Additionally, the significant fall in plasma IMA level is another indicator that MgSO4 reduces oxidative injury. All these results show that the administration of MgSO4 in pulmonary injury arising due to PP may have important effects in reducing IR injury.