Effects of microwave radiation on thymocytes in mice at different power densities / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of microwave radiation on thymocytes in mice at different power densities.</p><p><b>METHODS</b>The experimental animals were whole-body exposed to microwave radiation with frequency of 2,450 MHz, power density of 1, 5, 15 mW/cm(2) respectively 1 h everyday for 30 days. Then the thymus were taken out after the mice were decapitated. Thymus index, morphological characteristics of thymus were examined. The changes of thymus T-cell subgroups, cell cycle progression in thymocytes and cellular apoptosis were detected with flow cytometry (FCM).</p><p><b>RESULTS</b>The body weights of animals in 5, 15 mW/cm(2) irradiation groups [(28.10 +/- 1.46), (27.50 +/- 2.52) g] were lower than that of the control [(31.95 +/- 2.51) g] (P < 0.05). Pathological observation showed dark red piece of nucleus, some nuclei inclined to one side, slight increase in hassall body. The expressions of CD8 in 5, 15 mW/cm(2) irradiation groups (29.14% +/- 1.68%, 29.18% +/- 0.81%) were higher than that in control group (26.95% +/- 1.27%) (P < 0.05). The percentages of G(2) + M phase thymocytes in both radiation groups (12.24% +/- 1.82%, 11.19% +/- 1.36%) were lower than that in control group (14.58% +/- 0.64%) (P < 0.01). Thymocytic apoptosis rates in the three experimental groups (7.18% +/- 0.99%, 10.06% +/- 1.58%, 9.45% +/- 0.92%) were higher than that in control (4.25% +/- 1.63%) (P < 0.01), but the evident difference between 5 mW/cm(2) and 15 mW/cm(2) was not found (P > 0.05).</p><p><b>CONCLUSION</b>Sub-chronic microwave exposure (2 450 MHz, 5, 15 mW/cm(2)) could induce thymocyte apoptosis, cause pathological changes in thymus, and affect cell cycle progression, thus may inhibit the immune function of the animal.</p>

Effect of lead acetate on the nerve growth factor protein expression and the regulation of thyroid hormone / 中华劳动卫生职业病杂志

<p><b>OBJECTIVES</b>To study the effect of lead acetate on the expression of nerve growth factor (NGF) protein in rat brain and the regulation of thyroid hormone.</p><p><b>METHODS</b>Lead acetate was given to SD rats intraperitoneally ip. at the dosage of 25, 50 and 100 mg/kg respectively. 6-n-propyl-2-thiouracil (PTU) was used to make a hypothyroid model and then lead acetate was given at the dosage of 50 mg/kg body weight through i.p. The NGF protein expression in rat brain was observed by immunohistochemistry Triiodothyronine (T3), thyroxin (T4), TSH in serum and T3, T4 in brain tissue were determined by radio immunoassays (RIAs).</p><p><b>RESULTS</b>The average gray value of NGF protein in cerebral cortex of 50 mg, 100 mg treated groups (180.49 +/- 10.33, 169.72 +/- 19.75, respectively) were lower than the control (200.75 +/- 3.27, P<0.01). The area density of NGF protein in hippocampus of three treated groups (0.08 +/- 0.14, 0.12 +/- 0.02, 0.13 +/- 0.04, respectively) were significantly different from the control (0.025 +/- 0.015, P<0.05). The area density and the average gray value of NGF protein in lead acetate treated hypothyroid rat brain were of no significant changes. The levels of serum T3 in three treated groups [(0.68 +/- 0.02), (0.57 +/- 0.04), (0.54 +/- 0.02) microg/L respectively] and T4 [(28.30 +/- 1.83), (27.35 +/- 2.55), (24.00 +/- 3.01) microg/L] in serum were significantly lower while TSH [(6.34 +/- 1.13), (7.74 +/- 0.79), (9.16 +/- 0.77) IU] higher than those in the control [T3 (0.97 +/- 0.14) microg/L, T4 (54.50 +/- 3.70) microg/L and TSH (4.62 +/- 2.16) IU], and there was a good dose-response relationship. The levels of T3 in cerebral cortex of three treated groups [(13.26 +/- 0.81), (11.49 +/- 0.10), (10.42 +/- 1.19) pg/mg pro respectively] and T4 [(0.50 +/- 0.03), (0.49 +/- 0.13), (0.42 +/- 0.01) ng/mg pro] were significantly lower than those in control [(20.85 +/- 11.01) pg/mg pro, (0.76 +/- 0.14) ng/mg pro, P<0.05, P<0.01].</p><p><b>CONCLUSION</b>Lead could increase the NGF protein expression in rat brain, which may be regulated by thyroid hormone.</p>