Carnosine inhibits cataract formation and inactivation of Na+-K+ATPase induced by a glucocorticoid
- VernacularTitle:肌肽对糖皮质激素诱导白内障形成和Na+-K+ATP酶失活的保护作用
- Author:
Yi, SUN
;
Hong, YAN
- Publication Type:Journal Article
- Keywords:
carnosine;
glucocorticoid;
cataract;
Na+-K+ATPase
- From:
International Eye Science
2006;6(3):519-522
- CountryChina
- Language:Chinese
-
Abstract:
AIM: To investigate whether carnosine can inhibit cataract formation and protect Na+-K+ATPase against inactivation induced by a glucocorticoid.METHODS: Two hundred and twenty clear lenses cultured in vitro were randomly divided into five groups: control group (DMEM), steroid group (DMEM+Dexamethason 10μmol/L),lower concentration carnosine-treated group (DMEM+Dexamethason 10μ mol/L+Carnosine 2mmol/L), higher concentration carnosine-treated group (DMEM+Dexamethason 10μmol /L+Carnosine 5mmol/L) and carnosine group (DMEM + Carnosine 5mmol/L). Progression of cataract formation was evaluated daily using a dissecting microscope. On 1, 3, 5 and 7d, 10lenses of every group were homogenized and the activity of Na+-K+ATPase was measured by using spectrophotometer.RESULTS: During the incubation, mistlike opacity was observed in the lenses of the control group and carnosine group,but in the steroid group appeared dense nuclear opacity, while both two carnosine-treated groups came out visible demarcation between nuclear and cortical regions on 7d. A decrease in the activity of Na+-K+ATPase was found in the lens of the steroid group. On 3, 5, 7d, Na+-K+ATPase activity decreased 22.34% (P=0.002),47.98% (P＜0.001),75.37% (P＜0.001) compared with that at 1d, respectively. In the carnosine group,the activity of Na+-K+ATPase remained at the level of the control throughout the 7-d incubation, indicating that carnosine itself did not interfere with the original lens enzyme activity. In the lower concentration carnosine-treated group, on 3, 5, 7d,the activity of Na+-K+ATPase increased 10.8% (P＜0.05),44.6% (P＜0.01), 57.4% (P＜0.01) of control activity, respectively. In the higher concentration carnosine-treated group, on 3, 5, 7d, the activity of Na+-K+ATPase increased 11.3% (P＜0.05), 45.7% (P＜0.01), 57.6% (P＜0.01) of control activity,respectively. The activity of Na+-K+ATPase in both two carnosine-treated groups were only 6.7% and 6.5% lower than that of the control group after 7-d incubation. After the 7-d incubation, the Na+-K+ATPase activity of the lenses in the steroid group decreased significantly compared with carnosine-treated groups (P＜0.01).CONCLUSION: Carnosine prevents the cataract formation induced by a glucocorticoid, and significantly inhibits the inactivation of Na+-K+ATPase induced by a glucocorticoid.
