Distribution of Leptin Expression and Its Effect on the Recovery of Sepsis-induced Internal Disorders

Objective To explore the distribution of leptin expression and the effect of sepsis on leptin protein and mRNA levels. Methods Vital organ samples including hypothalamus, lung, liver, spleen, stomach, duodenum, kidney, epididymal fat pad and testis of normal rats were collected. The mRNA expressions of leptin in those samples were determined by RT-PCR. The sepsis rat model induce by cecal ligation and perforation (CLP) was established, setting groups of sham-operation, CLP model, CLP+intralipid injection, CLP+estradiol injection and CLP+insulin injection, as the latter three groups were set to intervene energy metabolism and neuroendocrine function. Radioimmunoassay was applied to measure serum leptin concentrations in each group at 12 h after injury, while RT-PCR was also used to detect Leptin mRNA expressions in hypothalamus, fat and lung after injury. Results Leptin mRNA expressions were confirmed in all the above nine vital organs, with the highest in kidney but the lowest in testis. The serum leptin level showed no significant difference between sham operation group and other four groups. Compared with sham operation group, the Leptin mRNA level in CLP group decreased significantly in hypothalamus, fat and lung, while that in the other three groups showed different changes. The effect of intralipid on Leptin mRNA expression was found to be a dual-direction pattern, with central stimulation but peripheral inhibition. Conclusion Leptin is widely expressed in multiple vital organs, and it may be a protective factor to promote recovery of sepsis-induced internal disorders.