Insulin-like Growth Factor I Group Research Articles

Combined Growth Hormone (GH) and Insulin-Like Growth Factor-I (IGF-I) Treatment is More Effective than GH or IGF-I Alone at Enhancing Recovery from Neonatal Malnutrition in Rats

The effect of hormonal therapy on enhancing recovery from neonatal malnutrition was assessed in rats. Malnutrition was induced by maternal food restriction (60% control intake) during lactation. On d 16 postpartum, restricted pups were refed by cross-fostering to control dams and were subcutaneously administered growth hormone (GH), insulin-like growth factor-I (IGF-I), GH + IGF-I or saline. At d 21, pups were weaned and continued hormonal treatments until d 39 postpartum. By d 39, body weight of GH (96% control) and GH + IGF-I- (98%) treated animals were normal, whereas IGF-I (88%) and saline- (85%) treated animals were still stunted. Hormone effectiveness was age dependent, with growth rates of GH + IGF-I-, IGF-I- and GH-treated pups being greatest between d 16 and 30, d 16 and 21 and after d 30, respectively. Protein accretion by d 39 was higher (P < 0.01) in GH and GH + IGF-I groups than saline- or IGF-I-treated groups. On d 39, serum IGF-I concentrations were as follows: GH + IGF-I > IGF-I > GH = saline (placebo), indicating that an elevated serum IGF-I was not required for GH-stimulated growth. Of the three hormonal treatments, GH + IGF-I therapy was most efficacious at promoting rapid and complete body weight recovery and supporting lean body mass accretion.

Expression and effect of microRNA-627 in human hypertrophic scar

Objective: To investigate the expression and effect of microRNA-627 (miR-627) in human hypertrophic scar. Methods: The experimental research method was used. From October 2019 to January 2020, hypertrophic scar tissue from 6 patients with hypertrophic scar (2 males and 4 females, aged (34±11) years) and the remaining normal skin tissue from 6 trauma patients (3 males and 3 females, aged (35±13) years) after flap transplantation were collected. The above-mentioned 12 patients were admitted to the General Hospital of Northern Theater Command and met the inclusion criteria. The mRNA expression of miR-627 was detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction. The 3rd to 5th passages of fibroblasts (Fbs) were isolated from hypertrophic scar tissue and cultured for subsequent experiments after identification. Fbs from hypertrophic scar were divided into miR-627 negative control group, miR-627 mimic group, and miR-627 inhibitor group. The corresponding sequences were transfected respectively. At 0 (immediately), 12, 24, 36, and 48 h after transfection, the cell viability was detected by thiazolyl blue method; at 24 h after transfection, the apoptosis was detected by flow cytometry; at 24 h after transfection, the protein expression levels of insulin-like growth factor Ⅰ (IGF-Ⅰ), type Ⅰ collagen, and α smooth muscle actin (α-SMA) were detected by Western blotting. Two batches of Fbs from hypertrophic scar were used, one batch was divided into IGF-Ⅰ wild type+miR-627 negative control group and IGF-Ⅰ wild type+miR-627 mimic group, and the other batch was divided into IGF-Ⅰ mutant+miR-627 negative control group and IGF-Ⅰ mutant+miR-627 mimic group. The corresponding sequences were transfected respectively. At 48 h after transfection, the expressions of luciferase and renal luciferase were detected by luciferase reporter gene detection kit, and the ratio of the two was calculated to reflect the activity of IGF-Ⅰ. Fbs from hypertrophic scar were divided into miR-627 negative control group, miR-627 mimic alone group, and miR-627 mimic+IGF-Ⅰ group, and were transfected with the corresponding sequences respectively. At 24 h after transfection, the protein expression levels of IGF-Ⅰ, type Ⅰ collagen, and α-SMA were detected by Western blotting. The number of samples in cell experiment was 3. Data were statistically analyzed with analysis of variance for factorial design, one-way analysis of variance, independent sample t test, and chi-square test. Results: The expression of miR-627 mRNA in hypertrophic scar tissue was 0.47±0.06, which was significantly lower than 1.12±0.23 in normal skin tissue (t=15.090, P<0.01). At 12, 24, 36, and 48 hours after transfection, the cell viability of miR-627 mimic group was significantly lower than that of miR-627 negative control group (t=9.918, 34.370, 13.580, 61.550, P<0.05 or P<0.01); the cell viability of miR-627 inhibitor group was significantly higher than that of miR-627 negative control group (t=4.722, 8.616, 13.330, 14.000, P<0.05 or P<0.01). At 24 h after transfection, compared with the apoptosis rate (8.42±0.47)% in miR-627 negative control group, (10.89±0.35)% in miR-627 mimic group was significantly higher (t=7.301, P<0.01), and (5.00±0.22)% in miR-627 inhibitor group was significantly lower (t=11.510, P<0.01). At 24 h after transfection, compared with the cell protein expressions of IGF-Ⅰ, type Ⅰ collagen, and α-SMA in miR-627 negative control group, those in miR-627 mimic group were significantly lower (t=25.470, 5.282, 7.415, P<0.01), and those in miR-627 inhibitor group were significantly higher (t=15.930, 8.857, 9.763, P<0.01). At 48 h after transfection, the luciferase/renal luciferase ratio of IGF-Ⅰ of cells in IGF-Ⅰ wild type+miR-627 mimic group was 0.463±0.061, which was significantly lower than 0.999±0.011 in IGF-Ⅰ wild type+miR-627 negative control group (t=16.852, P<0.01); the luciferase/renal luciferase ratio of IGF-Ⅰ of cells in IGF-Ⅰ mutant+miR-627 mimic group was 0.934±0.021, which was similar to 0.930±0.023 in IGF-Ⅰ mutant+miR-627 negative control group (t=1.959, P>0.05). At 24 h after transfection, the protein expressions of IGF-Ⅰ, type Ⅰ collagen, and α-SMA of cells in miR-627 mimic alone group were 1.623±0.070, 1.363±0.042, and 1.617±0.025, which were significantly lower than 2.723±0.045, 2.147±0.067, and 2.533±0.055 in miR-627 negative control group (t=22.831, 7.280, 26.220, P<0.01); the protein expressions of IGF-Ⅰ, type Ⅰ collagen, and α-SMA of cells in mimic+IGF-Ⅰ group were 2.477±0.102, 1.760±0.046, and 2.387±0.049, which were significantly higher than those of miR-627 mimic alone group (t=3.830, 8.286, 3.436, P<0.05 or P<0.01). Conclusions: miR-627 expression in human hypertrophic scars is down-regulated; miR-627 can inhibit the proliferation and promote the apoptosis of Fbs in human hypertrophic scar by targeted inhibition of IGF-Ⅰ expression.

Mechanism study of dendritic epidermal T lymphocytes in promoting healing of full-thickness skin defects wound on mice by regulating the proliferation and differentiation of epidermal stem cells in mice

Mechanism study of dendritic epidermal T lymphocytes in promoting healing of full-thickness skin defects wound on mice by regulating the proliferation and differentiation of epidermal stem cells in mice

Effect and mechanism of adipocyte co-culture on aquaporin-9 expression in HepG2 cells

Objective: To observe the effect of differentiated mature adipocytes on hepatic steatosis and aquaporin-9 (AQP9) expressions in HepG2 cells and further explore its possible mechanism of action. Methods: Human preadipocytes were cultured and differentiated to full maturity. HepG2 cells were co-cultured with non-differentiated adipocytes and differentiated mature adipocytes for 48 h, and then labeled as control group and experimental group. Oil red O staining and intracellular triglyceride content were performed on co-cultured HepG2 cells and simultaneous changes in phosphatidylinositol 3-kinase (PI3K) - serine/threonine kinase (Akt) signaling pathway, and AQP9 mRNA and protein levels were detected. The experimental group was co-cultured with recombinant human insulin-like growth factor-I (IGF-I), with the addition of 100ng/ml PI3K-Akt pathway agonist, labeled as experimental group + IGF-I group. The activation of PI3K-Akt pathway was verified by Western blotting (WB). The expression of AQP9 was detected by RT-q PCR and WB. The recombinant lentivirus LV-AQP9 or empty-loaded virus LV-PWPI was transfected with HepG2 cells by recombinant lentiviral transfection tecnique, and labeled as HepG2-AQP9 and HepG2-PWPI. The transfection efficiency was assessed by confocal laser scanning microscopy and RT-qPCR and WB detected the change of AQP9 expression level after virus transfection. Afterwards, the stable over-expressed HepG2-AQP9 cells and the empty-loaded HepG2-PWPI cells were co-cultured with differentiated mature adipocytes for 48h, and labeled as HepG2-AQP9 co-culture group, and then intracellular triglyceride content were detected with Oil red O staining. Finally, IGF-I was added to the HepG2-AQP9 co-culture group, which was recorded as HepG2-AQP9 co-culture + IGF-I group. Intracellular triglyceride content was detected with Oil red O staining, and WB verified PI3K-Akt signaling pathway activation and changes in AQP9 mRNA and protein levels. A t-test was used to compare the two independent samples. Results: The intracellular lipid droplets and triglyceride content (0.052 ± 0.005) in the experimental group was increased significantly than the control group (0.033 ± 0.003) (t= 5.225,P= 0.006), suggesting that adipocyte co-culture had induced steatosis in HepG2 cells. RT-qPCR and WB results indicated that the expression levels of AQP9 mRNA (3.615 ± 0.330) and protein levels (0.072 ± 0.005) in the experimental group were significantly higher than the control group (t= 13.708, 11.225,P= 0.005, < 0.001). WB results showed that the expression level of phosphorylated Akt (p-Akt) protein (0.116±0.003) in the experimental group was significantly lower than the control group (0.202 ± 0.003) (t= 27.136,P< 0.001). The total Akt protein was constant, and the p-Akt/total Akt (0.182 ± 0.017)was significantly lower than the control group (0.327 ± 0.019) (t= 2.431,P= 0.001), suggesting that adipocyte co-culture had inhibited PI3K- Akt signaling pathway in HepG2 cells and up-regulated the expression level of AQP9. WB results indicated that the expression level of p-Akt protein (0.194 ± 0.021) in the experimental group + IGF-I group was significantly higher than the experimental group (0.132 ± 0.003) (t= 5.082,P= 0.007). The total Akt protein was constant, and the p-Akt/total Akt (0.281 ± 0.009) was significantly higher than the control group (0.184 ± 0.132) (t= 10.311,P< 0.001). Simultaneously, RT-qPCR and WB results indicated that the expression levels of AQP9 mRNA (0.327 ± 0.347) and protein levels (0.042 ± 0.004) in the experimental group + IGF-I group were significantly lower than the experimental group (t= 33.573, 5.598,P< 0.001, 0.005), suggesting that adipocyte co-culture had possibility to regulate the expression level of AQP9 through the PI3K-Akt pathway. Confocal laser microscopy analysis showed that the transfection efficiency was more than 90%. RT-q PCR and WB results indicated that the expression levels of AQP9 mRNA and protein levels (0.373 ± 0.221) in HepG2-AQP9 group were significantly higher than HepG2-PWPI group (t=14.953, 28.931,P= 0.002 and 0.000), suggesting that the stable overexpression of AQP9 cell line was successfully constructed. The intracellular lipid droplets and triglyceride content in HepG2-AQP9 co-culture group was significantly increased (t= 5.478, 5.369,P= 0.005) than HepG2-PWPI co-culture group and HepG2-AQP9 co-culture+ IGF-I group, suggesting that the increased expression of AQP9 had promoted HepG2 steatosis in co-cultured adipocytes. WB results showed the expression levels of p-Akt protein (0.168 ± 0.006) and p-Akt/total Akt (0.265±0.009) in HepG2-AQP9 co-culture + IGF-1 group was significantly increased (t= 16.311, 8.769,P< 0.001) than HepG2-AQP9 co-culture group, while the expression levels of AQP9 mRNA (0.327 ± 0.034) and protein (0.375 ± 0.025) was significantly decreased (t= 33.573, 9.146,P< 0.001 and 0.001). Conclusion: Adipocytes co-culture can induce steatosis in HepG2 cells, and may participate in inhibiting PI3K-Akt signaling pathway to upregulate the expression of AQP9 in steatotic HepG2 cells.

Effects of skin γδ T lymphocytes on wound healing of mice through regulating proliferation and differentiation of mice epidermal cells

Effects of skin γδ T lymphocytes on wound healing of mice through regulating proliferation and differentiation of mice epidermal cells

Systemic arterial hypertension but not IGF-I treatment stimulates cardiomyocyte enlargement in neonatal lambs.

Although cardiomyocyte terminal differentiation is nearly complete at birth in sheep, as in humans, very limited postnatal expansion of myocyte number may occur. The capacity of newborn cardiomyocytes to respond to growth stimulation by proliferation is poorly understood. Our objective was to test this growth response in newborn lambs with two stimuli shown to be potent inducers of cardiomyocyte growth in fetuses and adults: increased systolic load (Load) and insulin-like growth factor I (IGF-I). Vascular catheters and an inflatable aortic occluder were implanted in lambs. Hearts were collected for analysis at 18 days of age after a 7-day experiment and compared with control hearts. Load hearts, but not IGF-I hearts, were heavier ( P = 0.001) because of increased mass of the left ventricle (LV), septum, and left atrium (40-50%, P = 0.004). Terminal differentiation and cell cycle activity were not different between groups. Myocyte length was 7% greater in Load lamb hearts ( P < 0.05), and binucleated myocytes, which comprise ~90% of LV cells, were 25% larger in volume ( P = 0.03). Myocyte number per gram of myocardium was decreased in all ventricles of Load lambs ( P = 0.01). Cells from the IGF-I group were not different by any comparison. These results suggest that the newborn sheep LV responds to systolic stress with cardiomyocyte hypertrophy, not proliferation. Furthermore, IGF-I is ineffective at stimulating cardiomyocyte proliferation at this age (despite effectiveness when administered before birth). Thus, to expand cardiomyocyte number in the newborn heart, therapies other than systolic pressure load and IGF-I treatment need to be developed.

Insulin-like growth factor I enhances the developmental competence of yak embryos by modulating aquaporin 3.

The objective of our present study was to determine the effects of insulin-like growth factor I (IGF-I) on the development of yak (Bos grunniens) embryos after cumulus-oocyte complex (COC) vitrification and warming followed by in vitro fertilization (IVF). In Experiment 1, the yak COCs underwent vitrification and then IVF. Embryos were incubated in synthetic oviductal fluid (SOF) supplemented with four concentrations (0, 50, 100 and 200ng/ml) of IGF-I, while the yak COCs without vitrification or IGF-I supplementation acted as the control group; the BAX, BCL-2, AQP3mRNA and aquaporin 3 (AQP3) protein expression levels in the five groups of blastocysts were evaluated using quantitative real-time PCR and immunofluorescence analyses. In Experiment 2, the groups described above were fertilized and incubated. The cleavage rate, blastocyst rate, total cell count per blastocyst and the rate of growth of the inner cell mass (ICM) and trophectoderm (TE) were evaluated. The results were as follows: (1) the AQP3 gene expression and protein expression in the control and 100ng/ml IGF-I treatment groups were the highest. (2) The BAX gene expression was the lowest and the BCL-2 gene expression was the highest in the control and 100ng/ml IGF-I treatment groups. (3) The rates of cleavage and blastocysts in the control and 100ng/ml IGF-I groups were higher than those in the other three groups. The total cell count per blastocyst in the vitrified and warmed 100ng/ml IGF-I group (106.7±4.9) and the control group (107.3±4.2) was higher than that in the vitrified and warmed 0ng/ml IGF-I (91.2±3.1), 50ng/ml IGF-I (92.3±3.7) and 200ng/ml IGF-I (92.4±3.7) groups. Therefore, we conclude that IGF-I can improve yak blastocyst developmental ability, cytomembrane permeability and formation of the blastocyst cavity after COC vitrification by improving the BAX, BCL-2 and AQP3 expression levels.

Insulin-like growth factor-I gene therapy increases hippocampal neurogenesis, astrocyte branching and improves spatial memory in female aging rats.

In rats, learning and memory performance decline during aging, which makes this rodent species a suitable model to evaluate therapeutic strategies of potential value for correcting age-related cognitive deficits. Some of these strategies involve neurotrophic factors like insulin-like growth factor-I (IGF-I), a powerful neuroprotective molecule in the brain. Here, we implemented 18-day long intracerebroventricular (ICV) IGF-I gene therapy in 28months old Sprague-Dawley female rats, and assessed spatial memory performance in the Barnes maze. We also studied hippocampal morphology using an unbiased stereological approach. Adenovectors expressing the gene for rat IGF-I or the reporter DsRed were used. Cerebrospinal fluid (CSF) samples were taken and IGF-I levels determined by radioimmunoassay. At the end of the study, IGF-I levels in the CSF were significantly higher in the experimental group than in the DsRed controls. After treatment, the IGF-I group showed a significant improvement in spatial memory accuracy as compared with DsRed counterparts. In the dentate gyrus (DG) of the hippocampus, the IGF-I group showed a higher number of immature neurons than the DsRed controls. The treatment increased hippocampal astrocyte branching and reduced their number in the hippocampal stratum radiatum. We conclude that the ependymal route is an effective approach to increase CSF levels of IGF-I and that this strategy improves the accuracy of spatial memory in aging rats. The favorable effect of the treatment on DG neurogenesis and astrocyte branching in the stratum radiatum may contribute to improving memory performance in aging rats.

Role and underlying mechanism of IGF-I/ERK signaling pathway in lung fibrosis

To explore the role and underlying mechanisms of insulin-like growth factor I (IGF-I)/extracellular signal-regulated kinase (ERK) signaling pathway in lung fibrosis. Alveolar epithelial cell A549 was used. The expressions of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) in A549 culture media stimulated by IGF-I were determined by enzyme-linked immunosorbent assay (ELISA). ERK inhibitor U0126 was used. And there were three groups of control, IGF-I stimulation and RK inhibitor plus IGF-I stimulation. The activity of ERK in three groups was measured by Western blot. The mRNA level and protein concentration of MMP-2 and MMP-9 in three groups were examined by quantitative real-time-polymerase chain reaction (qRT-PCR) and ELISA. The protein concentrations of MMP-2 and MMP-9 in cell culture media increased in 50, 100 ng/ml IGF-I groups as compared with 0 ng/ml IGF-I group ((18.30 ± 0.11), (21.80 ± 0.09) vs (13.52 ± 0.19) ng/ml and (0.34 ± 0.01), (0.39 ± 0.01) vs (0.25 ± 0.01) ng/ml, P < 0.001). And the protein concentrations of MMP-2 and MMP-9 in 100 ng/ml IGF-I group increased versus 50 ng/ml IGF-I group (P < 0.01). IGF-I stimulation group increased the expression of p-ERK1/2 versus control group (0.40 ± 0.01 vs 0.23 ± 0.02, P < 0.05) while ERK inhibitor plus IGF-I stimulation group decreased the expression of p-ERK1/2 versus IGF-I stimulation group (0.14 ± 0.03 vs 0.40 ± 0.01, P < 0.01). ERK inhibitor plus IGF-I stimulation group inhibited the mRNA levels of MMP-2 and MMP-9 versus IGF-I stimulation group (0.88 ± 0.03 vs 1.17 ± 0.05 and 0.82 ± 0.23 vs 1.81 ± 0.27, both P < 0.05) and decreased the concentrations of MMP-2 and MMP-9 in culture media versus IGF-I stimulation group ((21.70 ± 0.32) vs (29.15 ± 0.34) ng/ml and (0.22 ± 0.01) vs (0.29 ± 0.01) ng/ml, both P < 0.01). IGF-I induces the expressions of MMP-2 and MMP-9 in alveolar epithelial cell through ERK signaling pathway. And it is associated with the disruption of epithelial basement membrane and the development of lung fibrosis.

Insulin-Like Growth Factor I Inhibits Alveolar Bone Loss Following Tooth Extraction in Rats.

Alveolar bone is often lost after tooth extraction. Few studies have assessed the longitudinal changes in bone volume that occur within these extraction sites. To investigate the longitudinal morphological changes in extraction sockets following sustained continuous subcutaneous infusion of human recombinant insulin-like growth factor I (IGF-I). Fourteen rats were subjected to right mandibular first molar extraction. Experimental rats (n = 7) received a continuous subcutaneous infusion of human recombinant IGF-I (320 mg/day) for 3 weeks by osmotic minipump. Control animals were treated with saline via the same method (n = 7). All rats were then housed for an additional 3 weeks. Micro-CT scanning was performed immediately after tooth extraction and at 1, 2, 3, and 6 weeks after extraction. New bone formation was markedly higher in the IGF-I-treated group as compared with the control group. The loss in alveolar ridge height in the IGF-I group was significantly lower than that in the control group at each time point after extraction on the buccal side and at 2, 3, and 6 weeks on the lingual side. IGF-I treatment increases the volume of newly formed bone and reduces the loss in alveolar ridge height following tooth extraction.

Antepartal insulin-like growth factor concentrations indicating differences in the metabolic adaptive capacity of dairy cows.

Cows with different Insulin-like Growth Factor-I (IGF-I) concentrations showed comparable expression levels of hepatic growth hormone receptor (GHR). Suppressor of cytokine signaling 2 (SOCS2), could be responsible for additional inhibition of the GHR signal cascade. The aims were to monitor cows with high or low antepartal IGF-I concentrations (IGF-Ihigh or IGF-Ilow), evaluate the interrelationships of endocrine endpoints, and measure hepatic SOCS2 expression. Dairy cows (n = 20) were selected (240 to 254 days after artificial insemination (AI)). Blood samples were drawn daily (day -17 until calving) and IGF-I, GH, insulin, thyroid hormones, estradiol, and progesterone concentrations were measured. Liver biopsies were taken (day 264 ± 1 after AI and postpartum) to measure mRNA expression (IGF-I, IGFBP-2, IGFBP-3, IGFBP-4, acid labile subunit (ALS), SOCS2, deiodinase1, GHR1A). IGF-I concentrations in the two groups were different (p < 0.0001). However, GH concentrations and GHR1A mRNA expression were comparable (p > 0.05). Thyroxine levels and ALS expression were higher in the IGF-Ihigh cows compared to IGF-Ilow cows. Estradiol concentration tended to be greater in the IGF-Ilow group (p = 0.06). It was hypothesized that low IGF-I levels are associated with enhanced SOCS2 expression although this could not be decisively confirmed by the present study.

P.11.15 Recombinant human insulin-like growth factor-I (IGF-I) therapy in Duchenne Muscular Dystrophy (DMD): A 6-month prospective randomized controlled trial

Glucocorticoids (GC) delay motor decline in DMD, but cause significant endocrine adverse effects. IGF-I offers potential as a therapeutic agent; it may improve or preserve muscle function and counter GC effects of growth failure and insulin resistance. To determine if IGF-I therapy (1) improves or preserves muscle function and (2) improves linear growth in DMD. Prospective randomized controlled trial of IGF-I therapy in pre-pubertal, ambulatory, GC-treated DMD boys (n = 17) compared to controls (GC alone, n = 21). IGF-I 160 mcg/kg was given daily subcutaneously for 6 months. Primary motor outcome was 6-min walk distance (6MWD), and endocrine outcomes were height velocity and change in height SD score (ΔHtSDS). Other outcomes included changes in timed motor tests, cardiopulmonary function, insulin sensitivity and safety. The difference of 6MWD between control and IGF-I groups at 6 months was 8.5 ± 7.0 m (mean ± SEM, p > 0.5). There were no significant differences between groups for changes in cardiopulmonary and other motor functional outcomes. Height velocity in IGF-I treated subjects was double that of controls at 6 months (6.5 ± 0.4 vs. 3.3 ± 0.3 cm/yr, p In this first study of IGF-I therapy in DMD boys, 6 months of daily IGF-I significantly increased height velocity and HtSDS compared to controls, but there was no difference in motor functional outcomes.

Steady-state level of insulin-like growth factor-I (IGF-I) receptor mRNA and the effect of IGF-I on the in vitro culture of caprine preantral follicles

The objectives were to quantify insulin-like growth factor receptor-1 (IGFR-1) mRNA in preantral follicles on Days 0 and 18 of in vitro culture in the presence or absence of FSH, and to evaluate the effects of IGF-I on the rate of normal follicles, antral cavity formation, and in vitro growth and maturation of caprine oocytes on Days 0, 6, 12, and 18 of culture. The expression of IGFR-1 was analyzed using real-time RT-PCR before and after follicle culture. Preantral follicles were isolated from the cortex of caprine ovaries and individually cultured for 18 d in the presence or absence of bovine IGF-I (50 or 100 ng/mL). At the end of the culture period, the oocytes were submitted to IVM. The expression of IGFR-1 mRNA in preantral follicles cultured in vitro only approached being significantly higher in follicles supplemented with FSH when compared to follicles immediately after recovery (P < 0.06) and cultured without FSH (P < 0.1). There was a higher (P < 0.05) percentage of normal follicles on Days 6, 12, and 18 of culture in IGF-I 50 (97, 92, 67%, respectively) and IGF-I 100 (100, 90, 80%) groups versus the control (90, 64, 36%). In addition, the rate of antrum formation at 6 and 12 d of culture was higher (P < 0.05) in IGF-I groups (IGF-I 50: 72 and 90% and IGF-I 100: 69 and 85%) than the control group (41 and 59%). After 18 d of culture, the percentages of grown oocytes acceptable for IVM were higher (P < 0.05) in follicles cultured in the presence of IGF-I (82 vs 49%). Furthermore, follicles cultured in the presence of IGF-I 50 and IGF-I 100 had higher (P < 0.05) meiotic resumption rates (63 and 66%, respectively) than the control group (11%). In conclusion, treatment with FSH tended to increase IGFR-1 mRNA expression during the in vitro culture of preantral follicles and the addition of IGF-I to the culture medium clearly improved the in vitro development of caprine preantral follicles.

Effect of transforming growth factor β(1) and insulin-like growth factor-I on extracelluar matrix synthesis of self-assembled constructs of goat temporomandibular joint disc

To examine the effects of high and low concentrations of transforming growth factor (TGF) β(1) and insulin-like growth factor-I (IGF-I) on the extracelluar matrix synthesis of the self-assembled constructs of temporomandibular joint (TMJ) disc. The experimental groups of self-assembled constructs were exposed to IGF-I (10, 100 µg/L) and TGF-β(1) (5, 50 µg/L), the control groups were not added with any growth factors. All groups were examined at 3 and 6 weeks for gross morphological, histological, and biochemical changes. Safranin-O/fast green staining was used to examine glycosaminoglycan (GAG) distribution, picrosirius red and immunohistochemical staining to observe type I collagen distribution. Type I collagen contents were tested by ELISA assay kit, GAG contents were measured by Blyscan GAG assay kit, and the cell numbers were quantified with a Picogreen reagent kit. The growth factor groups all upregulated the matrix synthesis of the self-assembled constructs compared with control groups. TGF-β(1) (5 µg/L) and IGF-I (10 µg/L) were the two most potent concentration in increasing type I collagen and GAG synthesis and cells proliferation. IGF-I group (10 µg/L) produced nearly 2 times (109.16 ± 5.12 µg) as much type I collagen as the control group (69.13 ± 5.94 µg) at 3 weeks. The matrix contents and the number of the proliferated cells in control group and all GF groups at 6 weeks were more than those at 3 weeks. IGF-I (10 µg/L) is the most beneficial growth factor and can be applied in tissue-engineering stratigies of the temporomandibular joint disc. At the same time, the exposure time of growth factors is another key factor that affects matrix synthesis of TMJ disc constructs.

The effect of growth hormone (GH) and insulin-like growth factor-I (IGF-I) on in vitro maturation of equine oocytes

The objective of this study was to test the hypothesis that equine growth hormone (eGH), in combination with insulin growth factor-I (IGF-I), influences positively in vitro nuclear and cytoplasmic maturation of equine oocytes. Cumulus-oocyte complexes were recovered from follicles that were < 25 mm in diameter, characterized by morphology and were allocated randomly as follow: (a) control (no additives); (b) 400 ng/ml eGH; (c) 200 ng/ml IGF-I; (d) eGH + IGF-I; and (e) eGH + IGF-I + 400 ng/ml anti-IGF-I antibody. Oocytes were matured for 30 h at 38.5°C in air with 5% CO2 and then stained with 10 μg/ml propidium iodide (PI) to evaluate nuclear status and 10 μg/ml Lens culinaris agglutinin-fluorescein complex (FITC-LCA) to assess cortical granule migration by confocal microscopy. The proportion of immature oocytes that developed to the metaphase II (MII) stage in the eGH + IGF-I group (15 of 45) was greater than in the groups that were treated only with IGF-I (7 of 36, p = 0.03). Oocytes that reached MII in the control group (20 of 56; 35.7%) showed a tendency to be different when compared with eGH + IGF-I group (15 of 45; 33.3%, p = 0.08). The treated group that contained anti-IGF-I (15 of 33; 45.4%) decreased the number of oocytes reaching any stage of development when compared with eGH (47 of 72; 65.3%) and eGH + IGF-I (33 of 45; 73.3%) groups (p = 0.05) when data from MI and MII were combined. We concluded that the addition of eGH to in vitro maturation (IVM) medium influenced the in vitro nuclear and cytoplasmic maturation of equine oocytes. The use of GH and IGF-I in vitro may represent a potential alternative for IVM of equine oocytes.

In Vitro Development of Caprine Preantral Follicles Is Improved with Insulin-Like Growth Factor-I (IGF-I).

In vitro culture of preantral follicles is a powerful technique to study the basic mechanisms of folliculogenesis and also represents a promising approach to obtain viable embryos in vitro. Currently, the rates of embryo production from preantral follicles cultured in vitro are very low. Efforts are still required to improve this technique and make it a potential tool for in vitro embryo production. The control of folliculogenesis involves a complex interaction among endocrine, paracrine, and autocrine factors. The involvement of IGF-I in preantral and antral follicles has been elegantly evidenced by studies with IGF-I gene knockout mice. Although the importance of IGF-I on folliculogenesis of several species is well known, the effect of this growth factor on the in vitro culture of isolated caprine preantral follicles has not been studied. Thus, this study was developed to evaluate the effects of IGF-I on follicle survival, antral cavity formation, and in vitro growth and maturation of caprine oocytes. Preantral follicles were individually cultured for 18 days with α-MEM associated or not to IGF-I (50 or 100 ng/ml) in three treatments: 1) alpha-MEM; 2) alpha-MEM + IGF-I 50, and 3) alpha-MEM + IGF-I 100. At the end of the culture period, the oocytes underwent in vitro maturation (IVM). Results showed a higher (P<0.05) percentage of normal follicles on days 6, 12, and 18 of culture in IGF-I 50 (97%, 92%, 67%) and IGF-I 100 (100%, 90%, 80%) groups versus the control (90%, 64%, 36%). In addition, the rate of antrum formation at 6, 12, and 18 days of culture was significantly higher (P<0.05) in IGF-I groups (IGF-I 50: 72%, 90%, 92% and IGF-I 100: 69%, 85%, 85%) versus the control group (41%, 59%, 69%). After 18 days of culture, the percentages of grown oocytes acceptable for IVM were significantly higher (P<0.05) in follicles cultured in the presence of IGF-I (82% vs. 49%). Furthermore, follicles cultured in the presence of IGF-I 50 and IGF-I 100 had higher (P<0.05) meiotic resumption rates (63% and 66%, respectively) when compared to the control group (11%). Results of the present study demonstrated, for the first time, that the addition of IGF-I in the culture medium was beneficial to the in vitro development of caprine preantral follicles and the production of oocytes capable of resuming meiosis. (poster)

Insulin-Like Growth Factor I Serum Levels Influence Ischemic Stroke Outcome

Insulin-like growth factor I (IGF-I) is neuroprotective in animal models of stroke. We investigated whether serum IGF-I levels in patients with acute ischemic stroke influence stroke severity and outcome. Concentrations of IGF-I and IGF binding protein 3 were measured in serum samples obtained within 6 hours after stroke onset from 255 patients who took part in the placebo arm of the United States and Canadian Lubeluzole in Acute Ischemic Stroke Study. Stroke severity was assessed with the National Institutes of Health Stroke Scale. Multivariate analysis was performed to assess the overall shift in modified Rankin Scale score and changes in the National Institutes of Health Stroke Scale score at 3 months. Survival curves were plotted using the Kaplan-Meier method, and the Cox proportional hazard model was used for multivariate analysis to investigate factors influencing survival. After controlling for statistically relevant risk factors, subjects with high IGF-I levels or IGF-I/IGF binding protein 3 ratios had a better neurological and functional outcome at 3 months. Baseline stroke severity was not different between high and low IGF-I groups. In contrast to the low IGF-I group, neurological symptoms gradually improved from Day 3 in the high IGF-I group. Our results suggest that high serum IGF-I levels just after ischemic stroke onset are associated with neurological recovery and a better functional outcome.

Influence of IGF-I on buffalo ( Bubalus bubalis) spermatozoa motility, membrane integrity, lipid peroxidation and fructose uptake in vitro

The objective of the present experiment was to examine the influence of mean physiological concentration of insulin-like growth factor-I (IGF-I) on frozen–thawed Surti buffalo ( Bubalus bubalis) spermatozoa functional parameters, i.e., motility, plasmalemma integrity, acrosomal integrity, functional membrane integrity, lipid peroxidation and fructose uptake in vitro. Frozen–thawed semen samples ( n = 6) were washed in tris buffer and divided into two equal parts (control and IGF-I groups). Only in the IGF-I group, IGF-I (rhIGF-I analogue) was added to a final concentration of 100 ng/ml. The samples were incubated at 37 °C for 2 h and the assessments were made at 0, 30, 60, 90 and 120 min of incubation. The mean concentration of the buffalo seminal plasma ( n = 17) IGF-I was 116.83 ± 28.34 ng/ml (range 41.4–198.95). IGF-I had significant effect on the total motility ( P < 0.01), progressive forward motility ( P < 0.01), functional membrane integrity ( P < 0.05) and lipid peroxidation levels ( P < 0.05) during the 120-min study period as assessed by area under curve. Treatment with IGF-I increased ( P < 0.01) the total spermatozoa motility at 30, 60 and 90 min as compared to the control. The progressive forward motility was significantly ( P < 0.01) higher at 60 and 90 min of incubation. The addition of IGF-I resulted in significant ( P < 0.01) increase in straight-line velocity (VSL, μm/s) as compared to the control at 60 and 90 min of incubation. The linearity (%) was significantly ( P < 0.01) higher in IGF-I treated semen as compared to control at 60 min of incubation. Plasmalemma integrity in IGF-I group was significantly ( P < 0.05) higher than control at 30 and 60 min of incubation. The functional membrane integrity differed significantly ( P < 0.01) between groups (control and IGF-I) at 60 and 90 min of incubation. The percentage of acrosomal intact spermatozoa decreased continuously over a period of time in both the groups. As compared to 0 min of incubation, the significant ( P < 0.05) loss of acrosome was observed at 60 and 90 min of incubation in control (63.87 ± 3.17 vs. 58.52 ± 2.54) and IGF-I (61.60 ± 2.26 vs. 56.11 ± 2.12) groups, respectively. Lipid peroxidation levels were significantly lower in IGF-I group at 90 min ( P < 0.05) and 120 min ( P < 0.01) of incubation than the control group. Fructose utilization was significantly higher in IGF-I group as compared to control at 30 min ( P < 0.05) and 60 min ( P < 0.01) of incubation. The present study suggests that addition of IGF-I improve spermatozoa functional parameters by reducing lipid peroxidation levels.

High Serum Levels of IGF-I Contribute to Promotion of Endochondral Ossification in Mandibular Condyle and Cause its Specific Elongation in Acromegaly-like Rats

Mandibular protrusion accompanies acromegaly or acrogigantism. To clarify the detailed mechanisms, we used an acromegaly-like rat model recently developed by exogenous administration of insulin-like growth factor I (IGF-I). Human recombinant IGF-I (640 microg/day) continuously was infused subcutaneously to 10-week-old male rats (n=12) for four weeks. Control, sham-operated animals (n=12) were injected with saline alone. Twelve rats (six from each group) were killed immediately after ending administration at age 14 weeks. Another 12 rats (six from each group) were housed for an additional four weeks after treatment ended. Mandibular condylar length increased significantly in the IGF-I rats compared with the control rats, but no significant intergroup difference was found in the lengths of the coronoid and angular processes. Cartilaginous layer width, bone matrix volume, and the number of osteoblasts in the mandibular condyle increased significantly in the IGF-I group. These histopathological changes in the condyle disappeared after IGF-I administration was discontinued; however, the morphological change in condylar length remained. These findings suggest that mandibular protrusion in patients with acromegaly or acrogigantism may be evoked by superfluous elongation of the mandibular condyle and that such elongation can be induced by endochondral ossification caused by high IGF-I serum levels.

Profile and regulation of annexin II expression during early embryogenesis in cattle

The presence of annexin II (Ann-II) during the initial stages of bovine embryo development and the regulation of Ann-II expression by retinol and insulin-like growth factor I (IGF-I) were studied. Bovine embryos at different stages of development were produced in vitro on Synthetic Oviductal Fluid (SOF) medium (control group), SOF supplemented with retinol (retinol group; 0.1ng/ml), or IGF-I (IGF-I group; 10ng/ml). The embryos were processed for mRNA extraction, cDNA production and polymerase chain reaction (PCR) using Ann-II-specific oligonucleotides. Ann-II was detected in all stages of early embryo development, except for the 16-cell stage. The blastocyst rates were significantly higher (P&lt;0.05) in the group supplemented with retinol (37.8%, 45/119) during in vitro embryo culture (IVC) than in those cultured in SOF (20.5%, 24/117) or SOF with IGF-I (25.8%, 24/93). Semiquantitative analysis of Ann-II expression in embryos produced in medium supplemented with IGF-I or retinol revealed a lower expression of this gene when compared with embryos cultured in SOF (P&lt;0.05). The Ann-II expression was not different in embryos cultured in the presence of retinol and IGF-I. The presence of retinol increased the production of embryos in vitro by decreasing the expression of Ann-II in early-stage of bovine embryo.