| Objective: To investigate the effects of different dosages of cefaclor and bifidobacterium on the development of immune system and intestinal microflora in young rats.Methods: In the experiment, a total of 80 Sprague-Dawlay(SD) rats ,grade SPF, healthy,7days old,15g-20g.Rats were randomly divided into 7 groups: the 7days group (groupA),the control groups (group G), and treated groups(groupB,groupC,groupD,groupE,groupF). GroupA ,consisting of 8 rats, was sacrificed immediately. Group G was treated with saline while the treated groups were treated with a daily dose of 150mg/kg cefaclor, 50mg/kg cefaclor, 5 million Live bacterium , 15 million Live bacterium, 100mg/kg cefaclor then 2h later 10 million Live bacterium, respectively in 2weeks, consisting of 72 rats. 8 rats of G,B,C,D,E,F group were sacrificed at the age of 21 days respectively. The tissue from terminal ileum and feces were stored to measure. The CD4+,CD8+T cells of terminal ileum tissue were detected by SABC immunohisto- chemistry (IHC). A gram stain was done for fecal smear and then counted the populations of gram positive bacillus, gram negative bacillus, gram positive cocci, gram negative cocci and analysis the changes among them. Relative content of four bacteria in the intestin: bifidobacterium (BB), lactobacillus (LB), bacteroides fragilis (BF), clostridium botulinum (CL), were detected by the variation intestinal microflora by 16S rRNA fluorescent quantificative PCR.Results: 1. CD4+T Cells and CD8+T Cells detected by SABC IHC1.1 CD4+T Cells detected by SABC IHCThe gray values of CD4+T Cells of group B,C,F[respectively (158.94±10.08), (115.29±17.39),(107.71±16.62)]were all significantly higher than group G [(92.50±11.30)] (respectively P<0.01, P<0.01, P<0.05). Group C,F were all significantly lower than group B(P all<0.01), but there was no significance between group C and F (P>0.05). Group D,E[respectiveely(79.48±5.43),(77.04±7.72)]were all lower than G(P<0.05), but there was no significance between group D and E (P>0.05).1.2 CD8+T Cells detected by SABC IHCThe gray values of CD8+T Cells of group B,C [respectively (107.91±8.85),(103.78±10.30)]were all significantly higher than group G [(80.81±14.80)] (P all<0.01), while group D,E [respectively(59.28±5.81),(58.95±7.81)]were all lower than group G (P all<0.01). Group F[(101.95±11.67)]was markly higer than D and E (P all<0.01), but there were no significance between group F and G (P>0.05). There were no significance among group B,C and F (P all>0.05).2. Intestinal flora differential counting2.1 Sum total of the bacillus count,cocci count and bacillus/cocci ratioThe total cell numbers of bacillus in group B,C,F [respectively (177.00±3.42),(178.63±3.42),(178.00±3.46)]were all significantly lower than group G,D,E [respectively (196.75±1.36),(196.88±1.25),(196.88±0.99)] (P all<0.01). The total cell numbers of cocci in group B,C,F [respectively (23.00±3.42),(21.38±3.42),(22.13±3.52)]were all significantly higher than group G,D,E [respectively (3.25±0.89),(3.25±1.04),(3.13±0.99)] (P all<0.01). The ratios of bacillus to cocci in in group B,C,F [respectively (7.86±1.31),(8.60±1.75),(8.24±1.42)]were all significantly lower than group G,D,E [respectively (64.42±17.27),(66.56±22.41),(68.58±21.19)] (P all < 0.01). But there were no significance among group B,C and F in the total cell numbers of bacillus,cocci and bacillus/cocci ratio (P all>0.05), the same results were found in comparison among group G,D and E.2.2 The ratios of bacillus count to the total cell numbersThe ratios of bacillus count to the total cell numbers in group B,C,F [respectively (13.38±1.51)%,(24.06±3.89)%,(15.50±1.95)%]were all significantly lower than group G,D,E [respectively (48.31±2.60)%,(46.56±2.03)%,(46.63±2.89)%] (P all<0.01). Group B,F were all significantly lower than group C(P all<0.01), but there was no significance between group B and F (P>0.05). There were no significance among group G,D and E (P all>0.05).2.3 The ratios of cocci count to the total cell numbersThe ratios of bacillus count to the total cell numbers in group B,C,F [respectively (10.50±1.60)%,(9.75±1.51)%,(10.06±1.72)%]were all significantly higher than group G,D,E [respectively (1.25±0.27)%,(1.13±0.44)%,(1.19±0.46)%] (P all<0.01). But there were no significance among group B,C and F (P all>0.05), the same results were found in comparison among group G,D and E.3. Detecting the variation intestinal microflora by 16S rRNA fluorescent quantificative PCR3.1 The relative content of BBThe relative content of BB [respectively (0.17265±0.03219),(0.38493±0.01453),(0.40909±0.07239)] were all significantly higher than group G,D,E [respectively (0.62473±0.08555),(0.60160±0.05108),(1.12013±0.38711)] (P<0.01 or P<0.05). Group C,F were all significantly higher than group B(respectively P<0.01,P<0.05), but there was no significance between group C and F (P>0.05). Group G,D were all significantly lower than group E(P all<0.01), but there was no significance between group G and D (P>0.05).3.2 The relative content of LBThe relative content of LB in group B[(0.02117±0.00793)] was significantly lower than group G,C,D,E and F [respectively (0.09233±0.04382),(0.08768±0.00886),(0.11830±0.01404),(0.11705±0.01358),(0.09298±0.05705)] (P all<0.01). There were no significance among group G,C,D,E and F (P all>0.05).3.3 The relative content of BFThere were no significance among group G,B,C,D,E and F (P all>0.05).3.4 The relative content of CL The relative content of CL in group B[(0.00329±0.00303)] was significantly higher than group G,C,D,E and F [respectively (0.00017±0.00015),(0.00073±0.00065),(0.00016±0.00022),(0.00010±0.00004),(0.00154±0.00029)] (P all<0.01). Group F was higher than group G,D and E (P all<0.05), while there was no significance between group F and C (P>0.05). There were no significance among group C,G,D and E (P all>0.05).Conclusions:1. Different dosages of cefaclor could reduce Sprague-Dawlay rats'intestinal immunity, while different dosages of bifidobacterium could improve immune response. SD rats'intestinal immunity was maken vulnerable after bifidobacterium was given firstly and cefaclor secondly. It indicated that bifidobacterium didn't have an effect of protection on intestinal immunity against cefaclor.2. Different dosages of cefaclor could send SD rats into intestinal dysbacteriosis, and higher dosage of cefaclor was related to increased dysbacteriosis. A high dosage of bifidobacterium had a good effect on intestinal microflora, however, there was no significant effect on intestinal microflora with a low dosage of bifidobacterium. SD rats'intestinal dysbacteriosis was observed after bifidobacterium was given firstly and cefaclor secondly, that indicated bifidobacterium could not maintain intestinal microfloral stability effectively under the circumstances. |
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