Study On Changes Of Leptin, Growth Hormone And Insulin-like Growth Factor-1 After Traumatic Brain Injury

Objectvie:To explore the choice of fracture reduction occasion and the correlation between serum growth hormone(GH) levels after traumatic brain injury(TBI) and severity of TBI by observing dynamicly serum growth hormone level in traumatic brain injury patients with limbs fracture. To study changes and significance of serum level of leptin,GH and insulin-like growth factor-1 by observing dynamicly their serum levels and leptin level in cerebrospinal fluid(CSF) afer establishing a brain injury model of lateral fluid percussive impact in rabbits.Methods:A two-phase-work was designed. Part A:23 simple TBI patients and 22 TBI with limbs fracture patients were selected,who were phlebotomized blood 2ml at 1d,3d,7d and 14d respectively afer injury. The control group contains 30 cases of healthy men. Serum concentration of GH was assayed by the automate chemilu-minescence machine. Then compare GH level among the three groups,the incidence of GH increase at each time point and the incidence of patients whose GH level increased more than once at all time points within 14 days after TBI between the TBI group and the TBI with fracture group. Calculate the correlation between GH level at each time point and GCS score of patients in both TBI group and TBI with fracture group.Part B:25 adult male rabbits were randomly divided into TBI group (group D,17 rabbits) and control group (group E,8 rabbits) and 8 rabbits survived in group D. Another 25 rabbits were randomly divided into percussive impact group(group F,17 rabbits) and sham operation group(group G,8rabbits).And 9 rabbits in group E survived.Rabbits in group D and group F received fluid percussive impact while rabbits in group E and group G were drilled a 7mm window in skull without fluid percussive impact. All the rabbits were phlebotomized blood 0.5ml at 1d,3d,7d and 14d,and the serum was kept at -80℃.Then the concentrations of serum leptin, GH, IGF-1 and CSF leptin were tested by ELISA. Compared levels of serum leptin,GH and IGF-1 at all time points between group D and group E and calculated the correlation. Compare CSF leptin level in group F and group G.Results:Part A:The concentrations of GH at all time points in both simple TBI group and TBI with fracture group were higher than those in control group (P<0.05); The incidence of GH increase in the simple TBI group and the TBI with fracture group were 13.64%～36.36% and 21.74%～30.43% respectively;And the incidence of patients in the two groups whose GH level increased more than once at all time points within 14 days after TBI were 52.17% and 59.09% respectively; There was no significant difference in GH level between the simple TBI group and TBI with fracture group (P>0.05),and also in the incidence of GH increase (P>0.05); There were no correlation between GH levels and GCS score (P>0.05).Part B:Serum leptin levels at each time point of rabbits in group D were higher than those in group E (P<0.05); Group D were higher than group E in serum GH and IGF-1 concentration and CSF leptin level at ld,3d and 7d after injury (P< 0.05),and the difference was not statistically significant at 14d afer TBI (P>0.05); In group D,serum leptin levels correlated with serum GH levels positively at all time points (P<0.05); There were also positive correlations at all time points between serum GH level and IGF-1 level at all time points (P<0.05); At 3d after TBI,serum leptin level correlated positively with serum IGF-1 level (P<0.05),while at the other time points they had no correlation (P>0.05).Conclusions:GH levels of TBI patients increase with 2 weeks after injury; which can promote fracture healing; There is no correlation between serum GH levels and severity of TBI; Surgery for limb fracture of TBI patients should be done as early as possible when patients'vital signs are stable; Serum leptin level of TBI rabbits increase within 14 days after TBI; Serum GH and IGF-1 level and CSF leptin level have an increase within 7 days after injury,arid decrease to normal at 14d post-TBI; After TBI, serum leptin and GH,GH and IGF-1 are both positive correlated. Leptin level and IGF-1 level has no correlation except at 3d afer TBI; Leptin can promote secretion of GH and GH can promote secretion of IGF-1; Leptin,GH and IGF-1 have roles of promoting wound healing and growth and neural protection. Leptin-GH-IGF-1 will probably be a direction of endocrine therapy for TBI.