Objective To observe the effect of transcutanous electrical acupoint stimulation(TEAS)on the exercise ability of rats.Methods After stereotaxis surgery,twenty male adult SD rats wera randomly divided into control group (n=10)and TEAS group(n=10).Two days after surgery.the rats were trained to adapt the treadmill mnning and TEAS(continuous wave,2Hz,5mA)was applied to right Zusanli (ST 36) for 30min,once a day for 6 days.Basic microdialysis samples of extracellular serotonin(5-HT)in rats'dorsal raphe nucleus(DRN)were collected 7 days after surgery.During experiment,rats were running on treadmill (10m/min for 10min,then gradually increased to 24m/min for 1 hour,0% grade).Microdialysis samples were collected continuously until 5 hours after treadmill running.The frequency of brush-stimulation during the running was recorded.Meanwhile,plasma amino acid content was examined 5 hours after exercise.Results The frequencies of brush-stimulation during the treadmill running in control group and TEAS group were 2.04+0.46 and 0.40+0.080 times per minute,respectively (P<0.05).There were no significant differences in plasma total-TRP(T-TPP)and branched chain amino acid(BCAA)contents between two groups(P>0.05).However,plasma free-TRP(f-TRP)content,f-TRP/T-TRP ratio and f-TRP/BCAA ratio decreased significantly(P<0.05) in TEAS group as compared with the control group.Extracellular 5-HT levels in DRN in control group soon after exercise were higher than their base levels(P<0.05),and decreased in sequential two hours,and then increased significantly 3 hours and 4 hours after exercise as compared with that 2 hours after exercise(P<0.05).There was a slow decline in the levels of extracellular 5-HT in TEAS group at each time-point after exercise,and significant lower than that in control group within 5 hours after exercise(P<0.05).Conclusion TEAS atZusanli(ST36)can effectively improve exercised ability by reducing peripheral free-TRP level and transporting TRP into the brain,and thus decreasing the synthesis of 5-HT in the brain.

Objective: To investigate the effect of chromium picolinate on egg production, egg quality, serum biochemical indices and immune response. Methods: A total of 120 49 w old Beijing Red commercial layers were randomly allotted to one of five treatments, and fed a basal corn soybean meal diet and the basal diet supplemented with 0.4,2.0,10.0 or 20.0 mg/kg Cr as chromium picolinate under heat stress for 30 days.Results: Cr increased average egg weight(P0.20) on egg yield, feed intake and feed/egg ratio. Added Cr at 0.4 ,2.0,10.0 mg/kg enhanced (P

OBJECTIVETo investigate the effects of malathion on the testicular spermatogenic function of male rats and its working mechanism.

METHODSForty specific pathogen-free male Wistar rats were randomly and equally divided into four groups: three exposure groups and a control group. Malathion was administered orally to male rats in the exposure groups at 33.75, 54, and 108 mg/kg (1/32 LD₅₀, 1/20 LD₅₀, and 1/10 LD₅₀) for 60 days. Rats in the control group received an equal volume of water. The body weights of rats were measured after exposure. The organ weights and coefficients of the testes and epididymes were determined as soon as rats were sacrificed. The sperm motility, counts, and malformation rates were measured in the left epididymis. Histopathological changes, cell apoptosis, and the expression levels of Bcl-2/Bax in the testes of rats were observed using HE staining, terminal deoxynucleotidyl transferase-mediated dUPT-biotin nick end labeling, and immunohistochemistry SABC method.

RESULTSThe body weights and the testis weights in the exposure groups were significantly lower than those in the control group (P < 0.01). The exposure groups had significantly lower sperm motility and significantly higher sperm malformation rates than the control group (P < 0.01). The sperm counts were significantly lower in the exposure groups than in the control group (P<0.01). The sperm counts and motility were negatively correlated with exposure dose (r = -0.81, P < 0.01; r = -0.51, P < 0.01), while the sperm malformation rate was positively correlated with exposure dose (r = 0.85, P 0.01). The exposure groups had significantly higher spermatogenic cell apoptosis rates than the control group (P<0.01). The expression level of Bax was significantly higher in the exposure groups than in the control group (P<0.01), while the expression level of Bcl-2 was significantly lower in the exposure groups than in the control group (P < 0.01). Histopathological examination of the testes showed degenerative changes in the seminiferous tubules at various doses along with the increase in malathion exposure dose.

CONCLUSIONMalathion affects the testicular spermatogenic function of male rats and its working mechanism may involve cell apoptosis induced by down-regulation of Bcl-2 and up-regulation of Bax.

Animals ; Apoptosis ; drug effects ; Dose-Response Relationship, Drug ; Down-Regulation ; Epididymis ; Malathion ; toxicity ; Male ; Organ Size ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Random Allocation ; Rats ; Rats, Wistar ; Sperm Motility ; Spermatogenesis ; drug effects ; Spermatozoa ; Testis ; drug effects ; Up-Regulation ; bcl-2-Associated X Protein ; metabolism