Effect of alpha-melanocyte in rat models of renal ischemia-reperfusion injury / 中国组织工程研究

BACKGROUND: Kidney ischemia-reperfusion injury often combines with acute kidney and lung injury. The expression of cutin cel growth factor receptor (KGFR) and alpha sodiumchannel protein (α-ENaC) in kidney and lung after ischemia-reperfusion injury and the protective effect of α-melanocyte require further observation and research. OBJECTIVE:To explore the therapeutic effect of α-melanocyte on the expressions of KGFR and α-ENaC in rat models of ischemia-reperfusion injury. METHODS:A total of 30 healthy male Sprague-Dawley rats were randomly divided into control group, ischemia-reperfusion group and α-MSH group. Models of renal ischemia-reperfusion injury were established by 30-minute ligation of renal artery in the ischemia-reperfusion and α-melanocyte groups. Rats in the control group were only used to expose the renal artery, no ligation. Rats in the α-melanocyte group were intraperitonealy injected with α-melanocyte (0.25 mg/kg) at 30 minutes before model establishment. Rats in the ischemia-reperfusion group were injected with 4 mL of physiological saline. RESULTS AND CONCLUSION: Compared with control group, water content of kidney and lung increased significantly in rats of ischemia-reperfusion group and a-MSH group, while the levels of KGFR and α-ENaC of kidney and lung in rats were lower (P < 0.05). Compared with the ischemia-reperfusion group, water content of kidney and lung in rats of a-MSH group decreased significantly, while the levels of KGFR and α-ENaC of kidney and lung increased gradualy (P < 0.05). Moreover, edema was significantly lessened in the rat kidney and lung. Results confirmed that after renal ischemia-reperfusion injury, KGFR and α-ENaC expression was consistent to the kidney and lung injury. α-MSH could increase the protein and mRNA expression of KGFR and α-ENaC in kidney and lung of rats, reduce the kidney and lung injury, and exert a certain protective effect.

Superoxide Dismutase 1 Inhibits Alpha-Melanocyte Stimulating Hormone and Ultraviolet B-Induced Melanogenesis in Murine Skin

BACKGROUND: Over the last decade, the incidence of ultraviolet B (UVB)-related skin problems has increased. Oxidative stress caused by UVB induces the secretion of melanocyte growth and activating factors from keratinocytes, which results in the formation of cutaneous hyperpigmentation. Therefore, increasing the antioxidant abilities of skin cells is thought to be a beneficial strategy for the development of sunscreen agents. Superoxide dismutase 1 (SOD1) is an antioxidant enzyme that is known to exhibit antioxidant properties. OBJECTIVE: The purpose of this study was to investigate the effect of SOD1 on alpha-melanocyte stimulating hormone (alpha-MSH) and UVB-induced melanogenesis in B16F10 melanoma cells and HRM-2 melanin-possessing hairless mice. METHODS: The inhibitory effect of SOD1 on tyrosinase activity was evaluated in a cell-free system. Additional experiments were performed using B16F10 melanoma cells to demonstrate the effects of SOD1 in vitro, and HRM-2 melanin-possessing hairless mice were used to evaluate the antimelanogenic effects of SOD1 in vivo. RESULTS: We found that SOD1 inhibited melanin production in a dose-dependent manner without causing cytotoxicity in B16F10 melanoma cells. SOD1 did not inhibit tyrosinase activity under cell-free conditions. The results indicate that SOD1 may reduce pigmentation by an indirect, nonenzymatic mechanism. We also found that SOD1 decreased UVB-induced melanogenesis in HRM-2 melanin-possessing hairless mice, as visualized through hematoxylin and eosin staining and Fontana-Masson staining. CONCLUSION: Our results indicate that SOD1 has an inhibitory effect on alpha-MSH and UVB-induced melanogenesis, indicating that SOD1 may be a promising sunscreen agent.

Correlation between expression of α-melanocyte-stimulating hormone and melanin level in human skin autografts / 第二军医大学学报

Objective: To examine the expression of α-melanocyte-stimulating hormone (α-MSH) and the melanin in different kinds of human skin autografts and in the normal skins, so as to elucidate the role of α-MSH in hyperpigmentation in the skin autografts. Methods: Immunohistochemical technique was employed to detect the expression and distribution of α-MSH in skin autografts (including the full thickness skin autografts, medium thickness skin autografts, razor-thin skin autografts, and normal skins adjacent to the donor site and the recipient site). Masson-Fontana staining technique was used to detect the melanin contents in all the above skin specimens. Results: The location of α-MSH expression was at the cytoplasm of melanocytes and keratinocytes in epiderm; α-MSH was positive in most skin autografts and its expression was higher in the thinner skin autografts. The expression of α-MSH in all types of skin autografts was significantly different from that in normal skin (P<0.01); α-MS expression was also significantly different between all the skin autografts (P<0.01); α-MSH expression in normal skin around donor site and recipient site had no statistical difference. The contents of melanin in skin autografts was obvious increased compared with that in normal skin(P<0.01); the contents of melanin between all the skin autografts were also significantly different (P<0.01). The melanin contents increased with the decrease of skin autografts thickness. The expression of α-MSH was positively correlated with the contents of melanin in epidermis. Conclusion: The expression of α-MSH in skin autografts is positively correlated with the contents of melanin in skin autografts. Overexpression of α-MSH may play an important role in hyperpigmentation process of skin autografts.

Effects of α-melanocyte-stimulating hormone on the production of TNF-α and IL-10 by peripheral blood mononuclear cells from patients with psoriasis / 中华皮肤科杂志

Objective To investigate the effects of alpha-melanocyte-stimulating hormone (alpha-MSH) on the production of tumor necrosis factor-alpha (TNF-alpha) and intedeukin-10 (IL-10) by peri-pheral blood monohuclear cells (PBMCs) from patients with psoriasis vulgaris. Methods Heparinized peri-pheral blood was obtained from 20 patients with psoriasis vulgaris and 10 healthy human controls. PBMCs were isolated, cultured in complete medium, and stimulated with phytohemagglutinin (PHA) alone, the com-bination of PHA and various concentrations of alpha-MSH, or nothing. After another 48-hour culture, ELISA and real-time PCR were performed to measure the secretion levels of TNF-alpha and IL-10 in the super-natants of cultured PBMCs as well as the mRNA expression levels of TNF-alpha and IL-10 in PBMCs. Results The secretion level of TNF-alpha in the supematants of patient-derived PBMCs stimulated by nothing or PHA alone was significantly higher than that from normal control-derived PBMCs (329.87 ± 99.33 ng/L vs 116.95 ± 37.15 ng/L, 1756.01 ± 183.60 ng/L vs 1287.30 ± 152.36 ng/L, both P<0.01). alpha-MSH of all tested concentrations (10-13, 10-11, 10-7,mol/L) could inhibit the secretion of TNF-alpha by PBMCs com-pared with PHA alone (all P < 0.01), and the maximum effective concentration was 10-13 mol/L. On the con-Wary, a significant decrease was observed in the secretion level of IL-10 in the supematants of patient-derived PBMCs stimulated by nothing or PHA alone compared with normal control-derived PBMCs (P <0.05 or 0.01). Moreover, the secretion of IL-10 by PBMCs was promoted by alpha-MSH of all tested con-centrations (P < 0.01 or 0.05), with the maximum effective concentration being 10-13 mol/L (P < 0.01). The alpha-MSH of 10-13 mol/L down-regulated the mRNA expression of TNF-alpha (P < 0.001), but up-regnlated that of IL-10 (P < 0.001) in PHA-stimulated PBMCs from patients. Conclusion alpha-MSH can regulate the production of TNF-alpha and IL-10 by PHA-stimulated PBMCs from patients with psoriasis vulgaris.

The Effect of alpha-Melanocyte Stimulating Hormone on Renal Ischemia Reperfusion Injury / 대한이식학회지

PURPOSE: In ischemia-reperfusion induced renal injuries, cytokines, chemoattractant chemokines, adhesion molecules and nitric oxide play an important role. alpha-Melanocyte stimulating hormone (alpha-MSH) is a potent anti-inflammatory cytokine so the therapeutic effect of alpha-MSH on an ischemia-reperfusion induced acute renal failure is to be evaluated. METHODS: 40 male Spraque-Dawley rats were prepared for the experiment, they were classified into three classes (Sham, ischemic control and alpha-MSH injection). Both renal pedicles were clamped for 45 minutes. alpha-MSH (50 microgram) was injected intravenously three times, immediately before ischemia and reperfusion and 18 hour after reperfusion. Serum creatinine and histologic changes were analyzed between groups (Sham (n=6), ischemic control group (n=15), and alpha-MSH group (n=19)). RESULTS: Serum creatinine level decreased significantly at 24 hours after reperfusion in alpha-MSH treated animals (SCr24 0.78+/-0.23 mg/dL, 4.21+/-1.14 mg/dL, 3.01+/-1.19 mg/dL, repectively (P=0.008)), especially serum creatinine level at 48 hours after reperfusion much more dicreased in alpha-MSH group (SCr48 0.67+/-0.16 mg/dL, 4.21+/-2.03 mg/dL, 1.15+/-1.11 mg/dL, repectively (P=0.004)). Tubular neccrosis and neutrophil infiltration decreased signigicantly in alpha-MSH treated group (P=0.001). Mortality was noted 33.3% only at ischemic conrol group. CONCLUSION: we demonstrate the fact that alpha-MSH has protective role on ischemic renal injury and improves survival rates.

The Effect of alpha-MSH on Long-term Histologic Changes after Acute Ischemic Kidney Injury in Rats / 대한신장학회잡지

BACKGROUND: Ischemic acute renal failure (ARF) is increasingly recognized as involving chronic functional and structural sequelae. Ischemia reperfusion injury (I/R) plays a major role in delayed graft function and long-term changes after kidney transplantation, also. The present study was designed to evaluate the long-term changes after acute ischemic injury and whether renoprotection by alpha-MSH in the acute ischemic stage, could reduce the long-term sequelae. METHODS: In control group, ischemia/reperfusion injury was induced in male Sprague-Dawley rats by clamping Lt. renal pedicle for 15, 45, 60 minutes after removal of Rt. Kidney and followed by reperfusion. The animals in alpha-MSH group were injected alpha-MSH prior to reperfusion and then every day for 1 week. We measured BUN, creatinine at 24 hour after I/R injury, and in each group, 6 animals were sacrified at 1 week and 4 weeks after I/R injury to evaluate apoptosis, ED1, PCNA, and histopathologic changes. RESULTS: At 4 weeks after I/R injury, the remnant structural damage such as apoptosis, ED1 stained cells, MT (+) tubulointerstitial fibrosis were observed. alpha-MSH could reduce the initial functional injury, and apoptosis, ED1 stained monocyte, MT (+) tubulointerstitial fibrosis, also. CONCLUSION: Renal function was recoverd at 4 weeks after I/R injury, but structural sequelae such as apoptosis, fibrosis were remnant. alpha-MSH could attenuate initial functional damage and remnant fibrosis.

Drug Induced Cerebral Proerectile Effect in Anesthethetized Rats / 대한남성과학회지

PURPOSE: To examine the centrally elicited erectile effects of alpha-MSH, oxytocin, prostagladin E1, and anabolic steroids after intracerebroventricular administration. MATERIALS AND METHODS: We used anesthetized male Sprague-Dawley rats. After intracerebroventricular administration of normal saline (NS), alpha-melanocyte stimulating hormone (alpha-MSH), oxytocin acetate (OT), prostaglandin E1 (PGE1), methylprednisolone (MP), testosterone enanthate (TE) or 17beta-estradiol (E2) under stereotaxis, the intracavernosal pressure (ICP), systolic femoral artery pressure (FAP), heart rate (HR), time to first response, duration, and number of erectile responses and adverse reactions were evaluated for 60 minutes. To show whether erections were centrally elicited, the above criteria were re-evaluated after a bilateral pelvic neurotomy and bilateral orchiectomy. RESULTS: A cerebral proerectile effect was elicited only by alpha-MSH and OT with no significant changes of FAP or HR. With PGE1, significant changes in FAP and HR were observed. The ICP/FAP ratio was highest (0.49 0.03) with alpha-MSH. The mean time latency was shortest with OT (20.6 5.6 min). The mean duration was longest in alpha-MSH (11.6 8.7 min). The number of responses was highest with OT (3.6 0.7). Adverse reactions, such as stretching, yawning and ejaculation, were simultaneously observed during increases in ICP. In the cases of a bilateral pelvic neurotomy or bilateral orchiectomy, these elicited erectile responses disappeared. CONCLUSIONS: alpha-MSH had the most potent proerectile effect compared to OT and PGE1 as assessed by highest intracavernosal pressure as well as duration of erectile response. The results suggest that testosterone and the pelvic nerve were essential for the central proerectile response.

Electroacupuncture up-regulated arcuate nucleus ?-MSH expression in the rat of diet-induced obesity / 北京大学学报(医学版)

Objective: To investigate the effect of electroacupuncture (EA) on rat with diet induced obesity (DIO) and to explore the possible neurochemical mechanisms using the technique of immumohistochemisty. Methods:To establish DIO rat model by feeding the animals with high fat diet for 14 weeks. DIO rats were randomly divided into 4 groups: (1) 2Hz EA group, (2) 100Hz EA group, (3) restrain control group,(4) diet resistance (DR) group,(5) DIO group and (6) normal control group. EA treatment: (1) The acupoints used were Zusanli and Sanyinjiao on both legs. (2) The intensities of stimulation were 0.5, 1.0 and 1.5mA for 10 mins each. EA treatment was administered 3 times per week. Food intake and body weight were measured daily for 4 weeks. (3) The changes of the expression of ? melanocyte stimulating hormone (? MSH) in the hypothalamic arcuate nucleus (ARC) were measured with immunohistochemical semiquantitative analysis. Results: (1) The food intake and body weight of 2 Hz EA group and 100 Hz EA group were decreased significantly compared with the restrain control group and DIO group. (2) The number of ? MSH positive cells in hypothalamic ARC in 2 Hz EA and 100 Hz EA group was significantly higher than that in restrain control group and DIO group. The number of ? MSH positive cells in hypothalamic ARC in DIO group is significantly lower than those in DR group or normal control group. Conclusion: A decrease of ? MSH level in hypothalamus may be associated with diet induced obesity. The therapeutic effect on obesity produced by EA may be accounted for by the stimulation of pro opio melanocortin neurons in hypothalamic ARC to release ? MSH, which inhibits food intake , resulting in a decrease of body weight.

Effects of Subentaneous Injection of?-MSH on Alexandrite Laser Hair Removal in a Mouse Model / 中华皮肤科杂志

Objective To study the result of Alexandrite laser hair removal after subcutaneous in-jection of?-MSH in anagen-induced C57BL6mice.Methods Hair shafts were depilated by wax/resin mix-ture to induce hair follicles from telogen to anagen in60C57BL6mice.The mice were randomly divided in-to groups A,B,C and D.Groups A and B were injected with0.5mg/kg and0.25mg/kg of?-MSH,respec-tively,on the back skin subcutaneously once a day.Group C was injected with the same dose of normal saline.Group D was treated as blank control.Groups A,B and C were exposed to Alexandrite laser on ana-gen(substageⅣ).Biopsies were taken before treatment and0.5h,2and28days after treatment.Speci-mens were stained with Masson-Fontana method before treatment,and with haematoxylin and eosin after treatment.The cutaneous response was observed after laser hair removal.Hair regrowth was assessed28days after treatment.Results The mean gradation value of folliclar melanin was increased in the test groups than that in control group before laser hair removal.Extent of folliclar damage and cutaneous adverse reaction af-ter laser treatment was more severe in test groups than those in control group.Hair regrowth was less obvious in test groups than that in control group,while local hyperpigmentation was increased in test groups than that in control group28days after treatment.No scarring was observed in3groups.Conclusion Subentaneous injection of?-MSH could increase melanin of the hair,decrease hair regrowth,and enhance local pigmenta-tion after laser hair removal in anagen-induced C57BL6mice.

The Expression of the alpha-Melanocyte Stimulating Hormone (alpha-MSH) and Melanocortin-1 Receptor (MC1R) in the Epidermis of the Vitiligo / 대한피부과학회지

BACKGROUND: Vitiligo is a skin disease that is characterized by the loss of cutaneous pigmentation. alpha-Melanocyte stimulating hormone (alpha-MSH) is a neuroimmunomodulating peptide derived from proopiomelanocortin, and melanocortin-1 receptor (MC1R) is a surface receptor which is expressed by several other cutaneous cells including melanocyte and keratinocyte. Both of them have been known to be the main physiologic regulator for integumental pigmentation. OBJECTIVE: To evaluate the expression pattern of alpha-MSH and MC1R in the epidermis of vitiligo patients. METHODS: Specimens were obtained in lesional, perilesional and non-lesional skin in 10 patients with vitiligo and from 3 normal persons by the punch biopsy. And then, indirect immunofluorescence was done to show the pattern of expression of alpha-MSH and MC1R. RESULTS: Pattern of expression between alpha-MSH and MC1R was nearly the same. In vitiligo patients with stable disease state (7 of 10), the expression of alpha-MSH and MC1R in the non-lesional skin was more prominent than that in lesional area. In vitiligo patients with active disease state (3 of 10), the expression of alpha-MSH and MC1R in the lesional skin was more prominent than that in non-lesional area. CONCLUSION: Between the stable and active vitiligo patients, there was a different pattern of expression of alpha-MSH and MC1R in the lesional skin.

The Effect of alpha-MSH on Tumor Necrosis Factor-alpha and NFkappaB Activation in Cultured Human Proximal Tubular Cells during Simulated Ischemia / 대한신장학회잡지

BACKGROUND: Tumor necrosis factor a (TNF), potent proinflammatory cytokine, may be related with ischemia/reperfusion injury induced tubular cell inflammation and apoptosis. We examined TNF and its major nuclear transcriptional factor, NFkappaB activation in cultured human tubular cells in hypoxic condition and the effect of alpha-MSH, potent antiinflammatory agent, which have been reported to reduce renal I/R injury in rats. METHODS: Hypoxic culture condition was produced by oxidative pathway inhibitor (Antimycin 2 mM) and glycolytic pathway inhibitor (deoxy-D- glucose 2 mM and 10 mM) for 1 hour and re-oxygenation was performed by placing the cells in normal medium. The expression of TNF mRNA was studied by RT-PCR and NFkappaB DNA binding activity was analysed by Electomobility shift assays (EMSA) and cellular apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated dUTP biotin nick-end labelling (TUNEL) method and DNA laddering. These data were compared between the alpha-MSH and the vehicle-treated groups. RESULTS: Measured ATP level was 49% of control by luciferase-based assay kit. I/R injury caused an increase in TNF mRNA and NFkappaB activation and was accompanied by morphological evidence of apoptosis. alpha-MSH significantly reduced the degree of apoptosis, as well as TNF mRNA and NFkappaB activity (TNF/L19 mRNA ratio, vehicle/alpha-MSH: 105.15 +/- 16.5/18.75 +/- 0.85, p<0.05) (NFkappaB activity, vehicle/alpha-MSH: 5624/4803 densitometric index (DI), p<0.05). CONCLUSION: These findings suggest that alpha-MSH can decrease cellular apoptosis in hypoxic tubular cells and this protective effect of alpha-MSH may be related, in partially, with supression of TNF and NFkappaB activity.

The Effect of alpha MSH Analogues on Rat Bones

Melanocortin is the downstream mediator of leptin signaling and absence of leptin signaling in ob/ob and db/db mice revealed the enhancement of bone formation through the central regulation. While alpha-melanocyte-stimulating hormone (alpha MSH) inhibits the secretion of interleukin-1 alpha and tumor necrosis factor-alpha from the inflammatory cells, alpha MSH can also enhance clonal expansion of pro B cells linked to stimulation of osteoclastogenesis. Therefore, we tested the effect of melanocortin on bones. alpha MSH analogues [6His] alpha MSH-ND and [6Asn] alpha MSH-ND were synthesized and the radio-ligand receptor binding- and cyclic AMP generating activity were analyzed in China Hamster Ovary cell line over- expressing melanocortin receptors. The EC50 of [6His] alpha MSH-ND measured from melanocortin-1, 3, 4 and 5 receptors were 0.008 0.0045, 1.523 0.707, 0.780 0.405, and 250.320 42.234 nM, respectively, and the EC50 of [6Asn] alpha MSH-ND were 16.8 6.94, 271.8 21.95, 8.0 1.21, and 1132.5 635.46 nM, respectively. Four weeks after the subcutaneous injection of the analogues, the body weights in the [6His] alpha MSH-ND and the [6Asn] alpha MSH-ND treated groups (346.0 20.63 g vs. 350.0 13.57 g) were lower than that of the vehicle treated group (375.8 17.31 g, p 0.05). There was no difference in the total femoral BMD measured by dual x-ray absorptiometry among the three groups. Among the three groups, there were no differences in the total numbers of crystal violet positive- or alkaline phosphatase positive colonies, in the expression of Receptor Activator of Nuclear Factor Kappa-B ligand on the tibia and the total number of multinucleated osteoclast-like cells differentiated from primary cultured bone marrow cells. From the above results, no evidence of bone gain or loss was found after treatment of the alpha MSH analogues peripherally.

-Melanocyte Stimulating Hormone (MSH) decreases cyclosporine A induced apoptosis in cultured human proximal tubular cells

The pathogenesis of chronic cyclosporine A (CsA) nephrotoxicity has not been elucidated, but apoptosis is thought to play an important role in CsA induced tubular atrophy. Recently Fas-Fas ligand system mediated apoptosis has been frequently reported in many epithelial cells as well as in T lymphocytes. We investigated the ability of CsA to induce apoptosis in cultured human proximal tubular epithelial cells and also the effect of -MSH on them. Fas, Fas ligand, and an intracellular adaptor protein, Fas-associating protein with death domain (FADD) expression, and poly-ADP ribose polymerase (PARP) cleavage were also studied. CsA induced apoptosis in cultured tubular epithelial cells demonstrated by increased number of TUNEL positive cells and it was accompanied by a significant increase in Fas mRNA and Fas ligand protein expressions. FADD and the cleavage product of PARP also increased, indicating the activation of caspase. In -MSH co-treated cells, apoptosis markedly decreased with downregulation of Fas, Fas ligand and FADD expressions and also the cleavage product of PARP. In conclusion, these data suggest that tubular cell apoptosis mediated by Fas system may play a role in tubular atrophy in chronic CsA nephrotoxicity and pretreatment of -MSH may have a some inhibitory effect on CsA induced tubular cell apoptosis.

Effect of weight loss on cerebrospinal Fluid and Plasma Concentrations of NPY, alpha -MSH and leptin in Obese Women / 대한내분비학회지

BACKGROUND: Although leptin and its principal mediators, neuropeptide Y (NPY) and -melanocyte stimulating hormone (MSH) are postulated to play a pivotal role in the energy balance in experimental animals, the physiologic roles of leptin and its molecular targets are not fully identified in cases of human obesity. METHODS: The subjects consisted of 16 obese women (mean BMI 35.6 kg/m2) before and after weight loss that was induced by a 2 week-very low caloric diet (800 kcal/day) and 14 normal weight women (who had a mean BMI of 20.4 kg/m2). We evaluated the plasma and cerebrospinal fluid (CSF) leptin, NPY and alpha -MSH levels and their relationship in normal weight and obese women. Additionally, changes of these peptides during a negative energy balance (800 kcal/day) were assessed in causes of human obesity. RESULTS: Obese subjects exhibited a 6.3-fold higher plasma leptin level (21.9+/-1.2 vs 3.5+/-0.4 ng/mL, p<0.05) and a 2.8-fold higher CSF leptin level (0.29+/-0.02 vs 0.10+/-0.01 ng/mL, p<0.05) compared to control subjects. The CSF/plasma leptin ratio in normal weight subjects was 2.3-fold higher than that in obese subjects. After a weight loss in obese subjects, the plasma leptin level decreased by 40% and the CSF level decreased by 51%. The CSF/plasma leptin ratio was slightly lower than the baseline level. There was a positive linear correlation between CSF and plasma leptin level at the baseline in obese subjects (r= 0.74, p<0.05) and a positive logarithmic correlation in normal weight subjects and in obese subjects after a weight loss (r= 0.66, p<0.05). The BMI negatively correlated with the CSF/plasma leptin ratio (r=-0.86, p<0.05) in any subjects. Neither the baseline plasma levels nor the baseline CSF levels of NPY were different between the normal weight subjects and obese subjects. After a weight loss the CSF NPY level decreased significantly compared to the baseline values in obese subjects. The alpha -MSH levels in plasma and CSF did not differ significantly from controls in obese subjects at the baseline or after a weight loss. The baseline CSF leptin level neither correlated with the baseline CSF NPY level nor the baseline CSF alpha -MSH level. CONCLUSION: These results demonstrated that the efficiency of leptin delivery to the CNS is reduced in human obesity and that the CNS leptin uptake involves the combination of saturable and unsaturable mechanisms. A marked reduction in the CSF leptin levels compared to the plasma level after a weight loss in obese subjects can be a potent stimulus for the body to regain weight. In contrast to the results that were observed in experimental animals, the CSF NPY and alpha -MSH did not differ from the controls in human obesity and there was no significant correlation between the CSF leptin and CSF of these neuropeptides. This could have resulted from leptin resistance in cases of human obesity although the mechanisms for this resistance remain to be determined.

Effects of alpha-melanocyte stimulating hormone on the expression of intercellular adhesion molecule-1 and renal function in acute ischemic renal failure in rats / 대한내과학회지

BACKGROUND: Acute renal failure is a reversible process in majority of cases but mechanisms of renal injury or recovery are poorly understood. Recently neutrophil infiltration is reported to potentiate inflammatory and cytotoxic cascade in ischemic renal injury and alpha-melanocyte stimulating hormone has been reported to have a potent anti-inflammatory properties in a variety of animal models. We examined the beneficial effects of alpha-MSH in acute ischemic renal injury in rats and tried to clarify its action mechanism. METHODS: After unilateral nephrectomy, renal artery of contralateral kidney was clamped for 40 minutes and reperfused in female Sprague-Dawley rats. alpha-MSH (50(mu)g) and vehicle was injected intraperitoneally immediately after and 6, 24 hours after reperfusion. Biochemical, histological data, ICAM-1 mRNA, protein expressions and polymorphonuclear cell infiltration were examined. RESULTS: alpha-MSH significantly attenuated the renal injury, measured by plasma BUN and creatinine level and also the degree of severity of histological injury (BUN 125.2+/-14.6 mg/dL : 46+/-19.6 mg/dL (p=0.004), creatinine 3.65+/-0.81 mg/dL : 1.47+/-0.5 mg/dL (p=0.005) at 24 hours after reperfusion, BUN 88+/-12.5 mg/dL : 25.5+/-15.8mg/dl (p=0.002), creatinine 2.76+/-0.5 mg/dL : 0.93+/-0.2 mg/dL (p=0.002) at 72 hours after reperfusion and 5.4+/-1.94/ 2.6+/-0.77 (p=0.006) at 24 hours after reperfusion in histilogical grading system). In the alpha-MSH treated groups, ICAM-1 mRNA expression decreased significantly compared to the vehicle treated ischemic group in 72 hours after reperfusion (0.49+/-0.01/0.31+/-0.2, p<0.008). ICAM-1 protein expression also decreased in alpha-MSH treated group, but it was not statistically significant. Polymorphonuclear cell infiltration showed a significant decrease in the alpha-MSH treated group at 24 hours after reperfusion (5.05+/-1.8/1.59+/-0.4, p=0.009). CONCLUSION: alpha-MSH attenuates ischemic renal injury by inhibiting the expression of ICAM-1 and subsequent polymorphonuclear cell infiltration. These results provide a rationale of alpha-MSH as a potential therapeutic drug in acute renal failure.

Expression of signal transducing G proteins in human melanoma cell lines

Some malignant melanoma cells regress spontaneously by terminal differentiation, and understanding the mechanisms of this spontaneous regression can contribute to the development of a new therapy not only for melanoma but also for other cancers. The signal transducing G protein is one component of the signaling pathways for the differentiation-inducing molecules such as alpha-melanocyte-stimulating hormone (alpha-MSH) and cAMP. To investigate the role of G proteins in the differentiation process, we analyzed the expression of various G proteins by quantitative Western blot and cAMP response in human malignant melanoma cell lines. SK-MEL-3 cells expressed the largest amount of stimulatory G protein alpha subunit (G(s) alpha) and the largest amount of inhibitory G protein alpha subunit (G(i) alpha) was expressed in Malme-3M cells among the 4 melanoma cell lines analyzed in this experiment. The SK-MEL-28 cells exhibited largest amount of alpha subunit of G(q) and the beta subunits. The cAMP formation by forskolin stimulation was largest in the Malme-3M. The amount of cAMP formation did not show any correlation with the expression of G(s) alpha nor that of G(i) alpha. The population doubling time was longest in Malme-3M cells. In this experiment, we found that the melanoma cells vary widely both in the expression of various G proteins and in cAMP production depending on the cell lines.

Effect of ?-melanocyte stimulating hormone on serum cytokine levels in rats with acute respiratory distress syndrome / 中华麻醉学杂志

Objective To investigate the effects of a-melanocyte stimulating hormone (?MSH) on serum cytokine levels in rats with acute respiratory distress syndrome (ARDS) induced by acute hemorrhagic shock and intratracheal lipopolysaccharide (LPS) administration (two-hit model) .Methods Thirty male SD rats weighing (337? 25) g were randomly assigned to six groups of five animals in each group: group A normal control; group B ARDS control; group C-F treatment groups in which ?MSH 1.7 mg/kg was given at different time points - Ih before LPS(C), at the time as LPS was administratered (D), 1h after LPS (E) or together with and 3 h and 6 h after LPS (F) . The animals were anesthetized with intravenous thiopental 30 mg?kg-1 and tracheotomized and mechanically ventilated (FiO2 : 0.5, RR 100 bpm, VT12ml, I: E = 1:1.5) . Right common carotid artery was cannulated for BP monitoring, removal of blood and blood sampling. Acute hemorrhagic shock was induced by removal of blood and MAP was maintained at 45 mm Hg for 1 h, then the animals were resuscitated with reinfusion of removed blood and lactated Ringer's solution, then endotoxin (LPS 200 ?g/kg in 500 ?l normal saline). The criterion for ARDS was PaO2/FiO2

Effect of ?-MSH on the NO production and SOCS-3 mRNA expression in murine peritoneal macrophages induced by LPS / 中国病理生理杂志

AIM: To explore the anti-LPS mechanisms of ?-melanocyte-stimulating hormone (?-MSH), the effects of ?-MSH on the expression of SOCS-3 mRNA and the production of NO in murine peritoneal macrophages induced by LPS were investigated. METHODS: BALB/c mouse peritoneal macrophages were cultured in vitro and induced by LPS, ?-MSH and LPS with ?-MSH, respectively. The expression of SOCS-3 mRNA was detected using reverse transcription polymerase chain reaction (RT-PCR). NO produced in macrophages was tested with Griess reagent. RESULTS: The level of NO and the expression of SOCS-3 mRNA were significantly increased in macrophages stimulated with LPS.?-MSH markedly decreased the expression of SOCS-3 mRNA and almost completely inhibited the production of NO induced by LPS. CONCLUSION: These results suggest that the negative regulative circuits operated by SOCS are activated during the inflammation induced by LPS, but SOCS might not be involved in the anti-LPS mechanism of ?-MSH.