AIM:To study the effect of manganese(Mn)on heat stressprotein 70(HSPT0)synthesis in the brain and liver of new-born rats whose mother-rats were exposed to Mn.METHODS:32 female rats were randomly divided into fourgroups.One group was administrated with physiologicalsaline only as control group,the other three groups wereadministrated with 7.5,15 and 30 mg·kg~(-1)manganesechloride(MnCl_2)by intraperitioneal injection every two daysfor two weeks.After delivery,the mother-rats receivedMnCl_2 unceasingly for a week with the same method.Thenthe contents of Mn,Zn,Cu and Fe in the livers of the new-born rats were determined by atomic absorptionspectroscopy;The level of HSPT0 in the brains and thelivers of the new-born rats as detected by Western-dot-blotting,and the SOD activities were measuredsimultaneously.RESULTS:The contents of Mn in the livers of new-born ratsof the experimental groups(respective 1.38±0.18,2.73±0.65,3.44±0.89μg·g~(-1))were significantly increasedcompared with the control group(0.88±0.18μg·g~(-1);P<0.01);The contents of Fe in the livers of new-born rats of 15and 30 mg·kg~(-1)experimental groups(426±125,572±175μg·g~(-1),respectively)were significantly increased comparedwith the control group(286±42μg·g~(-1);p<0.05);the levelsof Zn in the livers of the new-born rats of three experimentalgroups(254±49,263±47,213±28μg·g~(-1),respectively)were lower titan those of the control group(335±50μg·g~(-1);respective P<0.05,P<0.01);and the levels of Cu showedno significant difference among the four groups(threeexperimental groups:75±21,68±241 and 78±18μg·g~(-1);control group:83±9μg·g~(-1);P>0.05).There was asignificant increase in the levels of HSP70 in the brains ofnew-born rats of the 30 mg·kg~(-1)group(19.5×10~3±1.3×10~3A;control group:14.3×10~3±1.4×10~3A;P<0.01),andthe levels of HSPT0 in the livers of new-born rats of threeexperimental groups(respective 19.6×10~3±3.9×10~3A,18.5×10~3±3.8×10~3A,22.4×10~3±1.9×10~3A)also increased than control group(13.3×10~3±1.0×10~3A;P<0.01),butthe SOD activities showed no significant difference amongbrains of the four groups(experimental groups:5.04±0.43,4.83±0.48,4.60±0.84 ku·g~(-1);control group:4.91±0.37ku·g~(-1);P>0.05).The SOD activities in the livers of 15mg.kg~(-1)group(5.41±0.44 ku·g~(-1))was lower than the controlgroup(5.95±0.36 ku·g~(-1);P<0.05).CONCLUSION:While mother-rats were exposed tomanganese,the metabolisms of Mn、Zn and Fe of new-bornrats in the livers were influenced and were situated in astress status,thus HSP70 syntheses is induced in the brainsand livers of new-born rats,but the mechanism of this effectin the developmental toxicity of Mn remains to be furtherstudied. AIM: To study the effect of manganese (Mn) on heat stress protein 70 (HSPT0) synthesis in the brain and liver of new-born rats whose mother-rats were exposed to Mn. METHODS: 32 female rats were differentiated into four groups. One group was administrated with physiologicalsaline only as control group, the other three groups wereadministered with 7.5,15 and 30 mg · kg ~ (-1) of manganese chloride (MnCl_2) every two days for two weeks. After delivery, the mother-rats received MnCl_2 unceasingly for a week with the same method. Contents of Mn, Zn, Cu and Fe in the livers of the new-born rats were determined by atomic absorption spectroscopy; The level of HSPT0 in the brains and the divers of the new-born rats as detected by Western-dot-blotting, and the SOD activities were measured sequentially .RESULTS: The contents of Mn in the livers of new-born rats of the experimental groups (each 1.38 ± 0.18, 2.73 ± 0.65, 3.44 ± 0.89 μg · g ~ -1)) were significantly increasedcompared with the co ntrol group (0.88 ± 0.18μg · g -1; P <0.01); The contents of Fe in the livers of new-born rats of 15 and 30 mg · kg -1 experimental groups (426 ± 125,572 ± 175 μg · g -1, respectively) were significantly increased compared with the control group (286 ± 42 μg · g -1; p <0.05); the levels of Zn in the livers of the new-born rats of three experimental groups (254 ± 49,263 ± 47,213 ± 28 μg · g -1, respectively) were lower titan those of the control group (335 ± 50 μg · g -1; respective P <0.05, P <0.01); and the levels of Cu showed no significant difference among the four groups (three experimental groups: 75 ± 21, 68 ± 241 and 78 ± 18 μg · g -1; control group: 83 ± 9 μg · g -1; P> 0.05 ) Was was asignificant increase in the levels of HSP70 in the brains of new-born rats of the 30 mg · kg -1 group (19.5 × 10 -3 ± 1.3 × 10 -3 A; control group: 14.3 × 10 ~ 3 ± 1.4 × 10 -3 A; P <0.01), and the levels of HSPT0 in the livers of new-born rats of three experimental groups (19.6 × 10 -3 ± 3.9 × 10 -3 A, 18.5 × 10 -3 ± 3.8 × 10 ~ 3A, 22.4 × 10 ~ 3 ± 1.9 × 10 ~ 3A) al so increased than control group (13.3 × 10 ~ 3 ± 1.0 × 10~ 3A; P <0.01), but the SOD activities showed no significant difference among brains of the four groups (experimental groups: 5.04 ± 0.43,4.83 ± 0.48,4.60 ± 0.84 ku · g -1; control group: 4.91 ± 0.37 ku · g -1; P> 0.05). The activities of the SOD in the livers of 15 mg · kg -1 (5.41 ± 0.44 ku · g -1) were lower than the control group ± 0.36 ku · g -1; P <0.05) .CONCLUSION: While mother-rats were exposed to mandarin, the metabolisms of Mn, Zn and Fe of new-bornrats in the livers were influenced and were situated in astress status, thus HSP70 syntheses is induced in the brains and livers of new-born rats, but the mechanism of this effect in the developmental toxicity of Mn remains to be furtherstudied.