OBJECTIVETo investigate the influence of induced nitric oxide synthase (iNOS) expression on apoptosis of thymocyte in burn rats, and to explore the relationship between NO and pathological lesion of the thymus gland in burn rats.

METHODSFifty-six male Wistar rats were enrolled in the study and randomized into control( C, n = 8,without treatment) , burn ( B, n = 24) , and S-methylisothiourea( SMT, n = 24) groups. Equal amount of isotonic saline solution and SMT(7. 5 mg/kg) were respectively intravenously infused into the rats in B and SMT groups after being inflicted with 30% TBSA full-thickness burns. The weight of thymus gland in each group were weighed, and thymocyte apoptosis and iNOS expression were determined with TUNEL method and immunohistochemistry, respectively at 6,24,72 postburn hours( PBH) , with 8 rats at each time-point. The number of apoptotic cells and the density of iNOS positive cells in thymus was measured by stereological method.

RESULTSThe weight of thymus in B group at 24 and 72 PBH [ (153+/- 14) , (91+/-22) mg] were obviously heavier than those in C group, but much lighter than those in SMT group ( P < 0.01). A few apoptotic cells and iNOS positive cells were observed in cortex and medulla of thymus in C group, while they were observed in B group at 6 PBH, and the number of cells began to increase at 24 PBH, distributing in medulla,parenchyma, the boundary of cortex, and medulla under capsule. The iNOS positive cells in B group at 24 PBH were distributed around the interlobular septum. A large number of cortical cells with brown staining were observed in B group at 72 PBH, and the number of iNOS positive cells also increased, with scattered distribution and clear cell boundary. Fewer positive cells with uneven distribution, no iNOS positive cells, and few apoptotic foci were observed in SMT group after burns. The density of apoptotic cells in B group at 24 and 72 PBH was (2. 428 +/-0. 728) x 10(-5)/microm(3) and (5. 586 +/- 1.233) x 10(-5)/microm(3), respectively, which was obviously higher than that in C and SMT group. The density of iNOS positive cells in B group was increased in a time-dependent manner( P <0. 05).

CONCLUSIONThe apoptotic rate of thymocyte in severely burn rats increases early after burns. The up-regulation of iNOS expression in thymus can promote apoptosis of thymocytes, while SMT can partially ameliorate this phenomenon.

Animals ; Apoptosis ; Burns ; metabolism ; pathology ; Gene Expression Regulation ; Isothiuronium ; analogs & derivatives ; pharmacology ; Male ; Nitric Oxide Synthase Type II ; metabolism ; Organ Size ; Rats ; Rats, Wistar ; Thymus Gland ; cytology ; metabolism

Adult ; Blood Coagulation ; Emergency Treatment ; Female ; Humans ; Intraoperative Period ; Liver Transplantation ; Male ; Middle Aged

Objective To explore the distribution and characteristics on genotype of Mycobacterium tuberculosis and the relationship between Beijing genotype and drug-resistant phenotypes in Tianjin city. Methods 656 clinical strains were collected from Tianjin Center for Tuberculosis Control and ten other Tuberculosis Institute in Tianjin from January 2008 to June 2009.Information regarding administration, clinical as well as laboratory findings of patients were collected.Proportion method was adopted to detect the susceptibility on four anti-tuberculosis drugs, namely streptomycin (SM), isoniazid (INH), rifampicin (RFP) and ehambutol (EMB). Both Beijing and non-Beijing genotypes were differentiated by multiplex PCR. The relationship between Beijing genotype and drug-resistant phenotypes was analyzed. Results In this study, the overall resistance rate of MTB was 26.98%, with multidrug-resistant rate was 6.25%. Among 656 MTB strains, 600isolates (91.46% ) belonged to Beijing genotype. There was significant difference between Beijing and non-Beijing genotype (x2=4.26, P=0.039) among the Tianjin household registered population.Concerning the drug resistance, there was no significant difference between the two groups.Conclusion Beijing genotype strains were the predominant one in Tianjin. The proportion of people infected with the Beijing genotype strains in Tianjin household registration of patients was significantly higher than the proportion of patients in the floating population in the same region.Results from the statistical analysis did not reveal any statistically significant association between Beijing genotype and drug resistance.