[Effects of ozone exposure on percentage of CD4(+)CD25(high)Foxp(3+) regulatory T cells and mRNA expression of Foxp3 in asthmatic rats].

OBJECTIVE: To investigate the effects of low-concentration ozone exposure on the percentage of CD4(+)CD25(high)Foxp(3+) regulatory T cells and the mRNA expression of transcription factor Foxp3 in asthmatic rats. METHODS: Sixty male Wistar rats were randomly divided into 4 groups (n = 15 for each): normal control group, ovalbumin (OVA) exposure group, ozone exposure group, and OVA+ozone exposure group. The OVA exposure group was sensitized and challenged with OVA to establish an asthma model; the normal control group inhaled aerosolized saline; the ozone exposure group inhaled low-concentration ozone; the OVA+ozone exposure group inhaled low-concentration ozone before being challenged with aerosolized OVA every day. The percentage of CD4(+)CD25(high)Foxp(3+) regulatory T cells in CD4(+) T cells was determined by flow cytometry. The levels of interferon-γ (INF-γ) and interleukin 4 (IL-4) in peripheral blood and lung tissue were measured by enzyme-linked immunosorbent assay. The mRNA expression of Foxp3 in lung tissue was measured by PCR. RESULTS: The percentages of CD4(+)CD25(high)Foxp(3+) regulatory T cells in OVA exposure group (6.12±1.03%) and ozone exposure group (5.87±1.26%) were significantly lower than that in normal control group (9.85±1.34%), and the percentage of CD4(+)CD25(high)Foxp(3+) regulatory T cells in OVA+ozone exposure group (3.31±0.85%) was significantly lower than those in normal control group and OVA exposure group (P < 0.01). The levels of IL-4 in plasma and lung tissue in OVA exposure group (plasma: 21.83±5.12 ng/L; lung tissue: 0.89±0.13 ng/L) were significantly higher than those in normal control group (plasma: 10.58±2.73 ng/L; lung tissue: 0.32±0.11 ng/L) (P < 0.01). The levels of IL-4 in plasma and lung tissue in OVA+ozone exposure group (plasma: 35.47±7.24 ng/L; lung tissue: 1.50±0.42 ng/L) were significantly higher than those in normal control group and OVA exposure group (P < 0.01). The levels of INF-γ in plasma and lung tissue in OVA exposure group (plasma: 61.78±23.45 ng/L; lung tissue: 0.69±0.21 ng/L] were significantly lower than those in normal control group [plasma: 158.89±60.23 ng/L; lung tissue: 1.86±0.29) (P < 0.01). The levels of INF-γ in plasma and lung tissue in OVA+ozone exposure group (plasma: 10.28±2.63 ng/L; lung tissue: 0.41±0.12 ng/L) were significantly lower than those in normal control group and OVA exposure group (P < 0.01). The mRNA expression of Foxp3 was significantly lower in the OVA+ ozone exposure group than in the normal control group (P < 0.05). CONCLUSION: Low-concentration ozone exposure may decrease the number of CD4(+)CD25(high)Foxp(3+) regulatory T cells and inhibit the mRNA expression of Foxp3 to promote Th1/Th2 imbalance in asthmatic rats, suggesting that ozone exposure may be one of factors that induce asthma attack.

[Effect of acrolein exposure on the percentage of CD4⁺CD25⁺ regulatory T cells and expression of transcription factor Foxp3 in asthmatic rats].

OBJECTIVE: This work was intended to investigate the effect of acrolein fog exposure on the ratio of CD4⁺CD25⁺ regulatory T cells (Treg) and expression of transcription factor Foxp3 in asthmatic rats. METHODS: Sixty 6 - 8 weeks male Wistar rats were randomly divided into 4 groups according to random number table (15 rats for each group) which were control group (animals were treated with saline), aerosolized ovalbumin (OVA) exposure group, acrolein exposure group and combined OVA and acrolein fog exposure group, respectively. The rats were exposed to air or/and to saline or OVA aerosol for 6-8 weeks respectively.24 h after the last challenge, 4 ml of peripheral blood and lung tissue were collected from each rat. The percentage of CD4⁺CD25⁺ T cells was determined by flow cytometry analysis. The concentration of interleukin-4 (IL-4) and γ-interferon (IFN-γ) in peripheral blood and lung homogenates were measured by ELISA. The protein expression of Foxp3 in the lung was detected by Western blotting. RESULTS: The percentage of CD4⁺CD25⁺T cells in aerosolized OVA group ((6.23 ± 1.11)%) was significantly lower than that in the normal saline group ((9.97 ± 1.23)%) (P < 0.01). The percentage of CD4⁺CD25⁺ T cells ((3.26 ± 0.84)%) in OVA combined acrolein fog exposure group was remarkably lower than that in the aerosolized OVA exposure group and in the normal saline group (P < 0.01). IL-4 in both plasma and lung ((22.57 ± 4.34), (0.86 ± 0.12) ng/L) was significantly increased in the OVA exposed rats compared with the normal saline group ((11.57 ± 2.86), (0.31 ± 0.10) ng/L) (P < 0.01). Further remarkable increase in IL-4 of both plasma and lung tissue was observed in the group exposed to both OVA and acrolein ((34.32 ± 6.21), (1.45 ± 0.32)ng/L) compared with the aerosolized OVA exposure group and the normal saline group (P < 0.05). γ-IFN of plasma and lung tissue in OVA exposed group ((59.67 ± 20.12), (0.56 ± 0.17) ng/L) was significantly decreased compared with the normal saline group ((151.74 ± 56.68), (1.54 ± 0.21) ng/L) (P < 0.01), and a further remarkable decrease in IFN-γ of plasma and lung tissue was observed in the group exposed to both OVA and acrolein ((10.12 ± 2.57), (0.49 ± 0.10) ng/L) compared with the aerosolized OVA exposure group and the normal saline group (P < 0.05). Protein expression of Foxp3 in the aerosolized OVA group (8.07 ± 0.24) was lower than that in the normal saline group (10.25 ± 0.31) (P < 0.01), while the protein expression of Foxp3 in OVA combined acrolein fog exposure group (6.38 ± 0.32) was lower than that in the normal saline group and the aerosolized OVA exposure group (P < 0.01). CONCLUSION: The number of CD4⁺CD25⁺ Treg cells and the expression of Foxp3 were likely to be altered by acrolein fog exposure, which might play an important role in acrolein induced Th1/Th2 imbalance in asthmatic rats.

[Effect of JNK signal transduction pathway in intense noise-induced apoptosis of vestibular hair cells in guinea pigs].

OBJECTIVE: To investigate the mechanism of intense noise-induced apoptosis of vestibular hair cells in guinea pigs and the effect of phosphorylated c-Jun N-terminal kinase (JNK) signal transduction pathway in intense noise-induced apoptosis of vestibular hair cells. METHODS: Thirty-two guinea pigs were randomly and equally divided into 1, 5, and 15 d experimental groups and control group. The guinea pigs in the experimental groups were exposed to 4 kHz narrow-band noise at 120 dB SPL for 4 h and then subjected to measurement of auditory brainstem response at 1, 5, or 15 d after noise exposure. In each group, four guinea pigs were used to prepare paraffin sections of vestibular hair cells, and the rest for extraction of total protein from vestibular hair cells. The apoptosis of vestibular hair cells was detected by terminal deoxynucleotidyl transferase (TdT)-mediated d-UTP nick-end labeling (TUNEL). The expression levels of p-JNK and pc-Jun were measured by immunohistochemistry and Western blot. RESULTS: TUNEL-positive cells were found in the vestibular hair cells in the experimental groups, most in the 1 d experimental group and least in the 15 d experimental group, but no positive cells were found in the control group. The immunohistochemical results showed that p-JNK and pc-Jun were detected in the cell nuclei in the experimental groups, but no p-JNK- and pc-Jun-positive cells were found in the control group. The Western blot showed that p-JNK and pc-Jun were increased and activated quickly at 1d after noise exposure, reached the peak levels at 5 d after noise exposure, and were then decreased gradually, but they were still at relatively high levels at 15 d after noise exposure. CONCLUSION: Intense noise can cause injury to vestibular hair cells by inducing cell apoptosis, and p-JNK marks the activation of JNK signal transduction pathway, suggesting that JNK signal transduction pathway plays an important role in intense noise-induced apoptosis of vestibular hair cells in guinea pigs.

Expression of phosphatidylinositol-3 kinase and effects of inhibitor Wortmannin on expression of tumor necrosis factor-α in severe acute pancreatitis associated with acute lung injury.

BACKGROUND: Acute lung injury (ALI) is a common and serious complication of severe acute pancreatitis (SAP). The study aimed to investigate the protective effect and mechanism of phosphatidylinositol-3 kinase (PI3K) inhibitor Wortmannin in SAP associated with ALI. METHODS: Ninety rats were randomly divided into three groups: sham operation (SO) group (n=30), SAP group (n=30), and SAP+Wortmannin (SAP+W) group (n=30). SAP model was induced by retrograde injection of 4% sodium taurocholate into the biliopancreatic duct of rats. The rate of lung water content, myeloperoxidase (MPO), matrix metalloproteinase 9 (MMP-9), protein kinase B (PKB), abdphosphorylation of protein kinase B (P-PKB) activity in the lung tissue were evaluated. RESULTS: In the SAP group, the p-PKB expression in the lung tissue began to rise at 3 hours after modeling, and peaked at 12 hours (P<0.05); the rate of lung water content, MPO and TNF-α activity were also gradually increased, and the degree of lung lesion gradually increased (P<0.05). In the SAP+Wortmannin group, the p-PKB expression in the lung tissue began to rise at 3 hours after modeling, and peaked at 12 hours; it was higher than that in the SO group (P<0.05), but significantly lower than that in the SAP group (P<0.05). The rest indicators in the SAP+Wortmannin group were also significantly decreased as compared with the SAP group (P<0.05). CONCLUSIONS: The expression of phosphatidylinositol-3 kinase/protein kinase B was elevated in severe pancreatitis rats with lung injury. This suggested that PI3K signal transduction pathway is involved in the control and release of proinflammatory cytokines TNF-α, which may play an important role in the pathogenesis of severe acute pancreatitis associated with lung injury. This finding indicated that Wortmannin can block the PI3K signal transduction pathway, and inhibit the release of inflammatory factor TNF-α.