Melatonin attenuates acute pancreatitis-associated lung injury in rats by modulating interleukin 22

Figure 1 Histology of pulmonary tissues and pathological scores of pancreatic tissues from rats in the sham operation, severe acute pancreatitis, and melatonin treatment groups. A-C: Histological changes of pulmonary tissues in the SAP group (A) 1 h, (B) 4 h, and (C) 8 h after experimental induction of SAP; D: Histological changes of pulmonary tissues in the SO group 8 h after mock induction of SAP; E-G: Histological changes of pulmonary tissues in the MT group (E) 1 h, (F) 4 h, and (G) 8 h after experimental induction of SAP (hematoxylin and eosin stain; ×200). H: Pathological scores of pancreatic tissues (n = 8). ^bP < 0.01 vs the MT group; ^dP < 0.01 vs the SO and MT groups. SO: Sham operation; SAP: Severe acute pancreatitis; MT: Melatonin treatment.

Figure 2 Changes in serum amylase levels from rats in the sham operation, severe acute pancreatitis, and melatonin treatment groups over time. Serum amylase levels differed significantly (P < 0.01) between each pair of time points in the SAP group, but not at different levels in the SO group (n = 8 rats per group). ^bP < 0.01 vs the SO group; ^dP < 0.05 vs the SO and SAP groups. SO: Sham operation; SAP: Severe acute pancreatitis; MT: Melatonin treatment.

Figure 3 Levels of mRNAs encoding interleukin 22 and T helper cell 22 in lung tissue samples from rats in the sham operation, severe acute pancreatitis, and melatonin treatment groups. A: Expression of IL-22 mRNA 1, 4 and 8 h after induction of SAP; B: Expression of Th22 mRNA 1, 4 and 8 h after induction of SAP. Levels of mRNAs encoding IL-22 and Th22 decreased with continued progression of SAP (P < 0.01). ^bP < 0.01 vs the SO group; ^dP < 0.01 vs the SO and SAP groups (n = 8 rats per group). SO: Sham operation; SAP: Severe acute pancreatitis; IL: Interleukin; Th: T helper cell; MT: Melatonin treatment.

Figure 4 Levels of interleukin 22 in lung tissue samples from rats in the sham operation, severe acute pancreatitis, and melatonin treatment groups. Levels of IL-22 at 1, 4 and 8 h after induction of SAP. Levels of IL-22 decreased with continued progression of SAP (P < 0.01). ^bP < 0.01 vs the SO group; ^dP < 0.01 vs the SO and SAP groups (n = 8 rats per group). SO: Sham operation; SAP: Severe acute pancreatitis; IL: Interleukin; Th: T helper cell; MT: Melatonin treatment.