Myocardial remodeling in rats with metabolic syndrome: role of Rho-kinase mediated insulin resistance.

Insulin resistance (IR) plays a critical role in metabolic syndrome (MS). Previous studies have demonstrated that activated ROCK is increased in MS patients. However, the effect of Rho-kinase (ROCK) on IR has not been definitely determined. Thus, the aims of the present study were to determine whether ROCK activation induces IR or affects myocardial structure and function, as well as the possible mechanisms underlying this process. Wistar rats fed high fat, high glucose and high salt diet sewed as model of MS and we used transmission electron microscopy, echocardiogram technology, and terminal deoxynucleotidyl transferase-mediated DNA nick-end labeling staining to identify any myocardial damage. The protein levels of MYPT-1 (characteristic of ROCK activation), IRS-1 and AKT were analyzed by immunohistochemistry and Western blotting. In hearts from MS rats, we found increased protein levels of phospho-MYPT-1 and phospho-IRS-1 (Ser307) and decreased phospho-AKT compared to levels in normal rats. In conclusion, the results suggest that ROCK-mediated IR is involved in the development of myocardial impairments in MS rats and that this effect is mediated probably via the IRS-1/PI3-kinase/AKT pathway.

[Effects of electroacupuncture on hepatic blood flow and lipid peroxidation in septic rats].

OBJECTIVE: To investigate the protection effects of electroacupuncture on injury of lipid peroxidation induced by liver ischemia in septic rats. METHODS: Forty-eight male SD rats were subjected to sepsis induced by cecal ligation and puncture (CLP), and were randomly divided into a Sham operation group (group A), a CLP model group (group B), a CLP model plus electroacupuncture at "Zusanli" (ST 36) group (group C), a CLP model plus electroacupuncture at the shame acupoint (group D), a vagotomy plus CLP model group (group E) and CLP model plus electroacupuncture group after vagotomy (group F), 8 rats in each group. CLP was performed in group E and group F after the abdominal vagotomy. Bilateral "Zusanli"(ST 36) points and the shame acupoint were electroacupunctured (2 mA, 2/100 Hz) for 1 hour in group C, group F and group D, respectively. The hepatic blood flow (HBF) was detected by a laser-Doppler flowmetry at 6 h after CLP. The plasma activity of alanine aminotransferase (ALT) was also determined and specimens of liver were harvested for evaluation of malondialdehyde (MDA), xanthine oxidase (XOD) and assessment of the rate of water content. RESULTS: The blood flow of the liver was (56.97 +/- 11.95) U in group C which was significantly lower than (80.12 +/- 19.57) U in group A but higher than (42.61 +/- 10.97) U in group B, (44.53 +/- 9.23) U in group D, (30.05 +/- 4.46) U in group E and (30.46 +/- 6.38) U in group F (all P < 0.05) 6 h after CLP. Meanwhile, the levels of MDA, XOD, ALT and the rates of water content in liver in group C were all significantly higher than those in group A, but lower than those in the other four groups (all P < 0.05). The levels of MDA, XOD, ALT and the rates of water content in liver in group E and group F were all significantly higher than those in group D (all P < 0.05), while the blood flow of the liver lower than that in group D (P < 0.05), and with no significant differences in all above measurements between group E and group F (all P > 0. 05). CONCLUSION: Electroacupuncture at "Zusanli" (ST 36) can promote hepatic blood flow, inhibit lipid peroxidation and alleviate hepatic edema and dysfunction in septic rats, which might be related with the completeness of cranial nerve.

[The protective effects of carbachol on visceral ischemia-induced lipid peroxidation injury in rats with sepsis].

OBJECTIVE: To investigate the effect of carbachol (CAR) on visceral perfusion and lipid oxidation injury in rats with sepsis. METHODS: Sixty-four Sprague-Dawley (SD) rats received cecal ligation and puncture (CLP) surgery, and they were divided randomly into two groups: septic model group (CLP group, n=32) and septic model with CAR-treatment group (CAR group, n=32). CAR (10 microg/kg, CAR group) or normal saline (CLP group) was immediately injected into penial vein. Sixteen animals in each group were used to observe the mortality rates 12 hours and 24 hours after CLP, and the remaining rats for measurement of variables of blood and tissue. At the 18 hours after CLP, the mean arterial pressure (MAP), the blood flow (BF) of liver, kidney and jejunum, the plasma levels of alanine aminotransferase (ALT) and creatinine (Cr) were measured. Animals were sacrificed after the aforementioned determinations, and specimens of liver, kidney and jejunum were harvested for evaluation of malondialdehyde (MDA), xanthine oxidase (XOD), and assessment of tissue water content (ratio of dry to wet weight) of those organs . The activity of diamine oxidase (DAO) in jejunal tissue was detected. RESULTS: The mortality rates of 12 hours and 24 hours of CAR group were 25.0% (4/16)and 50.0% (8/16) respectively, all significantly lower than those of CLP group [37.5% (6/16) and 75%(12/16), both P<0.05]. CAR treatment did not result in significant statistical difference in the levels of MAP compared with CLP group at 18 hours after CLP (P>0.05), but led to significant increases in BF of CAR group in liver, kidney and jejunum compared with those of CLP group (all P<0.05). The levels of XOD and MDA, as well as the tissue water content were significantly lower in CAR group than CLP group in kidney and jejunum (all P<0.05). The parameters of organ function were significantly different in CAR group compared with CLP group [ALT: (64.3+/- 8.3) U/L vs. (81.5+/-7.9) U/L, Cr: (96.4+/-7.0) micromol/L vs. (117.1+/-6.7) micromol/L, DAO: (0.20+/- 0.04) U/L vs. (0.12+/-0.03) U/L, all P<0.05]. CONCLUSION: The results indicate that CAR promotes visceral perfusion, inhibits lipid peroxidation production and alleviates visceral edema and dysfunction in rats with sepsis.

[The effects of electro-acupuncturing at Zusanli point on intestinal proinflammatory factors, diamine oxidase and tissue water content in rats with sepsis].

OBJECTIVE: To investigate the protective effect of electro-acupuncturing (EA) at Zusanli point on sepsis induced ischemic and oxygen free radical intestinal injury in rats with sepsis. METHODS: Thirty-two male Wistar rats were used to reproduce sepsis by cecal ligation and puncture (CLP), and they were randomly divided into four groups (each n=8): CLP+EA (CLP/EA), CLP+sham EA (CLP/SEA), vagotomy+CLP+SEA (VA/CLP/SEA) and vagotomy+CLP+EA (VA/CLP/EA). Zusanli point was electro-acupunctured with constant voltage (2-100 Hz,2 mA for 30 minutes) immediately after CLP surgery. Abdominal vagotomy was performed in rats in VA/CL/SEA and VA/CLP/SEA groups. Six hours after CLP, the mucosal blood flow of jejunum (JMBF) was measured. Animals were sacrificed after 6 hours and specimens of jejunum were harvested for evaluation of malondialdehyde (MDA), xanthine oxidase (XOD), diamine oxidase (DAO) and assessment of the water content (WCR). RESULTS: JMBF and the activity of DAO of CLP/EA group were markedly higher, and the levels of XOD, MDA and WCR in jejunal tissue were obviously lower than those of CLP/SEA group (all P<0.05). The levels of JMBF and DAO of the VA/CLP/SEA group and VA/CLP/EA group were significantly lower, and XOD, MDA and WCR obviously higher than those of the CLP/EA group ( all P<0.05 ). There were no statistically differences in all above measurements between the VA/CLP/EA group and the VA/CLP/SEA group (all P>0.05). CONCLUSION: The results indicate that EA at Zusanli point obviously increased JMBF and DAO, and alleviated tissue edema and insult of intestinal mucosa. Vagotomy could weaken or eliminate the effects of EA. It is suggested that cholinergic anti-inflammatory pathway is one of the main mechanisms of intestinal protective effect of EA at Zusanli point.

[The effect of carbachol on pulmonary vascular permeability and lung water content during oral fluid resuscitation of burn shock induced by a 50% total body surface area full-thickness flame injury in dogs].

OBJECTIVE: To investigate the effects of carbachol (CAR) on pulmonary vascular permeability and pulmonary water content during oral fluid resuscitation of burn shock. METHODS: Twelve male Beagle dogs with intubation of carotid artery and jugular vein for 24 hours were subjected to a 50% total body surface area (TBSA) full-thickness burn, then they were equally divided into oral resuscitation (OR) and OR plus CAR groups (OR+CAR). Dogs were given either a glucose-electrolyte solution (GES) in OR group or GES containing CAR (20 microg/kg) in OR+CAR group by gavage within 24 hours after burn. Dogs in each group were given intravenous fluid resuscitation after 24 post burn hour (PBH). The delivery rate and volume of GES was in accordance with that of Parkland formula. Respiratory rate (RR), arterial partial pressure of oxygen (PaO(2)), extravascular lung water index (ELWI) and pulmonary vascular permeability index (PVPI) were determined before burn (0 hour), and at 2, 4, 8, 24, 48 and 72 PBH. At 72 PBH or before death, dogs were sacrificed to collect lung tissue for evaluation of myeloperoxidase (MPO), malondialdehyde (MDA), and assessment of the tissue water content by dry to wet weight. RESULTS: Compared with those before burn, RR, ELWI and PVPI were greatly increased, and PaO(2) obviously decreased in two groups after burn (all P<0.01). At 72 PBH, PaO(2) returned to pre-burn level, while RR, ELWI and PVPI were still higher than pre-burn levels. RR, ELWI and PVPI at 4, 8 and 24 PBH, and PaO(2) at 8, 24, 48 PBH in OR+CAR group were respectively lower or higher than those in OR group (P<0.05 or P<0.01), but those measurements showed no statistical differences between two groups at 72 PBH (all P>0.05). MPO, MDA and lung water contents in OR+CAR group were significantly lower than those in OR group at 72 PBH [(2.64+/-0.38) U/mg vs.(4.12+/-0.46) U/mg, P<0.01; (3.60+/-0.54) micromol/mg vs.(5.14+/-0.62) micromol/mg, P<0.01; (77.40+/-0.56)% vs. (78.30+/-0.54)%, P<0.01]. CONCLUSION: The results indicate that CAR inhibits inflammatory response and oxidative damage in lung tissue, and alleviates pulmonary vascular permeability and lung edema during oral fluid resuscitation of burn shock.

[Vitamin alleviates visceral lipid peroxidative injury in dogs during oral fluid resuscitation of burn shock].

OBJECTIVE: To investigate the effect of vitamin C (VC) on visceral lipid oxidative injury during oral fluid resuscitation of burn shock. METHODS: Twelve male Beagle dogs were surgically prepared for arterial and venous cannulation, and 24 hours later they were subjected to a 50% TBSA full-thickness flame injury. In the first 24 hours after burn dogs were resuscitated with gastric infusion of either glucose-electrolyte solution (GES group, n = 6) or GES containing 250 mg/kg of VC (GES/VC group, n = 6). The delivery rate and volume of GES was in accordance with that of Parkland formula (4 ml x kg(-1) x 1% TBSA(-1) in the first 24 hours). In the second 24 hours all animals received delayed i.v. fluid resuscitation. At end of 72 hours after injury, animals were sacrificed, and specimens of heart, lung, liver, kidney and jejunum were harvested for evaluation of xanthine oxidase (XOD), malondialdehyde (MDA) and assessment of the tissue water content (ratio of dry to wet weight) of organs. The plasma levels of alanine aminotransferase (ALT), creatinine (Cr), MB isoenzyme of creatine kinase (CK-MB) and diamine oxidase (DAO) were determined at same time. RESULTS: At 72 hours after burn it was showed significant higher activities of XOD in GES/CAR than GES group in heart, kidney and jejunum, and lower contents of MDA in heart, lung, liver, kidney and jejunum (P all < 0.01). Tissue water contents were significantly lower in GES/CAR than GES group in heart [(75.4 +/-1.1)% vs (78.5 +/- 0.8)%], lung [(68.1 +/- 0.9)% vs (73.9 +/- 1.0)%], liver [ (75.2 +/- 0.8)% vs (78.3 +/- 1.2)%], kidney [(73.8 +/- 1.1)% vs (78.1 +/- 0.8)%] and jejunum [(76.3 +/- 0.8)% vs ( 80.4 +/- 0.6)] respectively, all P < 0.01. The levels of ALT, CK-MB, Cr and DAO in GES/CAR group were (46.6 +/- 2.49) U/L, (43.4 +/- 7.05) mol/L, (7156 +/- 596) U/L and (1.86 +/- 0.45) U/L respectively, all significantly lower than those of the GES group [(86.9 +/- 7.89) U/L, (95.2 +/- 1.23) mol/L, (8023 +/- 384) U/L and (2.68 +/- 0.61) U/L respectively, all P < 0.05]. CONCLUSION: The results indicated that vitamin C alleviated visceral tissue edema and organ injury by inhibiting free radical production during oral fluid resuscitation of burn shock.

[Observation on the effect of vitamin C in alleviating peroxidative damage in gut of dogs during enteral fluid resuscitation of severe burn shock].

OBJECTIVE: To investigate the effect of vitamin C (VC) on alleviating peroxidative damage in gut of dogs during enteral fluid resuscitation of severe burn shock. METHODS: Eighteen male Beagle dogs were subjected to 50% total body surface area (TBSA) full-thickness burn 24 hours after duodenostomy and cannulation of cervical artery and vein. The dogs were divided into no resuscitation (NR) group (no treatment after burn), enteral resuscitation (ER) group, and ER+VC group according to the random number table, with 6 dogs in each group. Dogs in ER and ER+VC groups were respectively infused with glucose-electrolyte solution (GES) and GES containing 250 mg/kg VC through duodenostomy tube 30 minutes after burn. The infusion rate and volume of GES were in accordance with Parkland formula. Venous blood of dogs was drawn before (0) and at 2, 4, 6, and 8 post burn hours (PBH) to determine the activity of diamine oxidase (DAO) in plasma. Dogs were sacrificed at PBH 8 to collect specimens of jejunum tissue for determining the content of malondialdehyde (MDA), and activity of myeloperoxidase (MPO), xanthine oxidase (XOD) and superoxide dismutase (SOD), and assessment of the water ratio of intestinal tissue by dry-wet weight method. RESULTS: 50% TBSA burn injury resulted in significant elevation of DAO in every group. The activity of DAO in ER group was obviously higher than that in NR group at PBH 6 and 8 (P < 0.05), but DAO activity in ER+VC group was significantly lower than those in the other two groups after PBH 2 (P < 0.05 or P < 0.01). MDA content, MPO and XOD activity and the water ratio of intestinal tissue [(5.74 +/- 0.51) nmol/mg, (2.08 +/- 0.46) U/g, (58.4 +/- 3.8) U/mg, (81.5 +/- 1.8)%] in ER group at PBH 8 was respectively significantly higher than that in NR group [(5.43 +/- 0.25) nmol/mg, (1.55 +/- 0.21) U/g, (50.1 +/- 2.8) U/mg, (78.3 +/- 1.5)%, P < 0.05 or P < 0.01]. While the activity of SOD in ER group (72 +/- 12) U/mg was lower than that in NR group (97 +/- 20) U/mg. MDA content, MPO and XOD activity and water ratio of intestinal tissue in ER+VC group was respectively lower than that in ER group, with activity of SOD in the former group higher than that in the latter group (P < 0.01). CONCLUSIONS: Vitamin C can alleviate peroxidative damage and tissue edema in gut induced by ischemia and reperfusion, and intestinal complications during oral rehydration during burn shock can be reduced.

[Study on intestinal absorption rate of glucose electrolyte solution during enteral resuscitation of 35% total body surface area burn injury in dog].

OBJECTIVE: To investigate the intestinal absorption rate of glucose-electrolyte solution (GES) during enteral resuscitation of burn injury in Beagle dogs, and compare the effect of enteral intake with that of intravenous infusion resuscitation. METHODS: Twelve male Beagle dogs were subjected to a 35% total body surface area (TBSA) full-thickness flame III degree injury. Thirty minutes after burn, each dog was given either enteral resuscitation with a GES (EGES group) or intravenous resuscitation with lactated Ringer's solution (IVLR group), and the amount and speed of replenishment of fluid were in accordance with Parkland formula. In the first 8 hours post burn, intestinal absorption rates of water and Na+ were continuously assessed using phenol red as a nonabsorbable marker for water absorption rate. The plasma volume (PV) was measured by the dye (indocyanine green) dilution technique, and the plasma concentration of Na+, mean arterial pressure (MAP) cardiac output (CO), and urine volume were also determined in the first 8 hours. All above measurement were performed in animals without anesthesia. At the end of 8-hour-period of experiment, the remnant fluids in the intestine were collected to calculate the total volume of fluid absorbed in 8 hours. RESULTS: The intestinal absorption rates of water and Na+ reduced markedly down to lowest level (21% and 37% of pre-injury level) at 3.5 hours post burn, and then increased slowly. But the mean absorption rate of water was similar to infusing rate according to Parkland formula [(99+/-47) mlxh(-1)xm(-1) vs. (81+/-11) mlxh(-1)xm(-1), P>0.05]. The total fluid absorbed by intestine was (94.8+/-3.7)% of the total fluid infused within 8 hours post burn. There were no significant differences in plasma concentration of Na+, MAP and CO between two groups at 8 hours post burn. The urine volume and PV at 4 hours in EGES group were lower than those in IVLR group (both P<0.05), but those indexes at 8 hours showed no significant difference between two groups (both P>0.05). CONCLUSION: Intestinal absorption rate of fluid given according to Parkland formula after burn injury is sufficient to resuscitate shock in animals suffering from a 35%TBSA full-thickness burn. Enteral resuscitation with GES may attain a similar therapeutic effect in expanding PV and maintain hemodynamic parameters.

[Effect of carbachol on intestinal mucosa blood flow and absorption rate of glucose-electrolyte solution during enteral resuscitation for 50% total body surface area full-thickness burn injury in dog].

OBJECTIVE: To investigate the effect of carbachol (CAR) on blood flow of intestinal mucosa and absorption rate of glucose-electrolyte solution (GES) during enteral resuscitation of burn shock in dog. METHODS: Eighteen male Beagle dogs were subjected to a (51.2+/-2.6)% total body surface area (TBSA) full-thickness flame injury, and fluid resuscitation was given according to Parkland formula 0.5 hour after burn. Animals were randomly divided into intravenous infusion of GES group (VGES group, n=6), enteral infusion of GES group (EGES group, n=6) and EGES containing 0.25 microg/kg of CAR group (EGES/CAR group n=6). In the first 8 hours post burn, intestinal absorption rate of water and Na+, intestinal mucosa blood flow (IBF), the plasma volume (PV) and plasma concentration of Na+ were continuously determined without anesthesia. At the end of 8 hours animals were sacrificed, and specimens of gut tissue were taken to determine the activity of Na+-K+-ATPase. RESULTS: The intestinal absorption rate of water and Na+ was reduced markedly after burn in two enteral resuscitation groups and much lower than pre-injury levels and the expected infusing rate according to Parkland formula. It was found that the absorption rate of water and Na+ from 1.5 hours and 2.5 hours in EGES/CAR group were significantly higher compared with those in EGES group (all P<0.05). During 8 hours after burn, only 47.1% and 63.8% of fluids enterally infused in EGES and EGES/CAR groups were absorbed by the gut. The volume of fluid absorbed and the fluid absorption rate were significantly higher in EGES/CAR group than those in EGES group (P<0.05). Incidence of gut intolerance (diarrhea) was 83% in EGES group, which was higher than that of in EGES/CAR group (50%). IBF was significantly decreased compared with pre-injury levels in all groups. Enteral infusion of CAR led to a significant elevation of IBF in EGES/CAR compared with GES group from 4 hours after burn, but it was still lower than pre-injury levels and those in VGES group. The Na+-K+-ATPase activity between three groups ranked as follows: VGES group>EGES/CAR group>EGES group (P<0.05). Within 8 hours post injury, PV and plasma concentration of Na+ in two enteral resuscitation groups were much lower than those in VGES group, but from 4 hours after burn the values in EGES/CAR group were higher than those in EGES group (all P<0.05). CONCLUSION: 50%TBSA full-thickness flame injury led to a markedly decrease in intestinal absorption rate of water and Na+. The total volume of fluid absorbed by intestine in 8 hours was significantly lower in enteral resuscitation groups compared to the regime of the Parkland formula. CAR promoted intestinal absorption rate and PV by increasing the intestinal blood flow and Na+-K+-ATPase activity, and it seems to exert a helpful effect on the resuscitation of burn shock with electrolyte solution per oral route.