| In the present study ,the grass carp(Ctenopharyngodon idellus) cell line ZC-7901 and the Colossoma Brachypomum cell line CBS were used as in vitro model systems to study the effects of cold stress on the cell membrane fluidity, the level of cacium ion, the contents of malondialdehyde(MDA),the level of C>2 and the system of antioxidative enzymes in the fish cells.The microviscosity( n) of the grass carp cell ZC-7901 under the treatment of 2-3 ℃ cold stress for 6h, 12h, 24h, 48h, 72h is 1.110, 0.926, 0.726, 0.646, 0.696 times those of the control growing at the normal temperature(28℃); the lipid fluidity (LFU) was 0.862,1.118,1.610,1.927,1.716 times; the membrane fluiditiy was 0.901, 1.080, 1.377, 1.547, 1.435 times respectively. While the microviscosity( n) of the CBS under the treatment of 8℃ cold stress was 1.068, 0.905, 0.937, 1.024, 1.071 times those of the control(37℃); the LFU was 0.912, 1.154, 1.098, 0.966, 0.908 times; the membrane fluiditiy was 0.937, 1.105, 1.068, 0.976, 0.934 times respectively. The results showed that the membrane fluidity of both the ZC-7901 cells and the CBS cells began to decrease for the relatively shorter time after 6h cold stress. With the time of cold stress lengthening, the membrane fluidity of the ZC-7901 cells increased, reaching the highest degree at 48h, then began to decrease, but was still higher than that of the controlWhile the CBS cells' membrane fluidity reached the highest degree at 12h, then began to decrease. At 72h, it was lower than that of the control. From the results, it can be concluded that the ZC-7901 cell still can maintain appropriate membrane fluidity under cold stress, while the CBS cell only can do in a degree for a short time.The calcium ion (Ca2+) level in the ZC-7901 and CBS cell cytoplasm increased after cold stess at 6h, and reached the highest level at 12h, then began to decrease. At 72h, the level of Ca2+ of the former was a little lower than that of the control. However the level of Ca2+ in the later cell decreased to the lowest point at 24h but still higher than that of the control, then with the time of cold stress lengthening, the level of Ca2+ became higher. The results indicated that after coldstress the ZC-7901 cell can keep calcium homeostasis, while the CBS cell can only regulate the level of Ca2+ in a restricted degree for short time, with the time of cold stress becoming longer, the equilibrium of Ca2+ was disturbed.The contents of MDA of the ZC-7901 cell under the treatment of 2-3 ℃ cold stress for 6h, 12h, 24h, 48h, 72h was 1.40, 1.75, 1.36 ,1.31, 1.27 times those of the control respectively. The level of 02 in the ZC-7901 reached the highest degree at 6h after cold stress, then becoming lower while still a little higher than that of the control. The contents of MDA of the CBS was 1.06, 1.14, 1.22, 1.26, 1.25 times those of the control respectively.The level of 02 in the CBS reached the highest degree at 6h after cold stress, and began to decrease but still higher than that of the control.Under the same treatment of cold stress, the ATPase activity of the ZC-7901 cell was 0.522,0.896,1.246,3.716,12.455,10.873 times that of the control; the inhibition rates of catinomycin D (final concentration,0.1 ag/ml) and puromycine(final concentration, lug/ml) on the activity of ATPase after 48h cold stress were 50.8% and 64.3% ; the ATPase activity of the CBS was 0.710, 0.567, 0.805, 0.832, 0.899, 0.808 times that of the control; the activity of SOD activity was 0.892, 1.5, 1.35, 1.26, 1.22 times; the CAT activity was 0.913, 2.27, 6.73, 1.78, 1.13 times; the POD activity was 0.809, 0.905, 1.5, 1.01, 1.004 times; the GSH-Px activity was 0.604, 1.30, 1.08, 1.07, 0.987 times respectively. The activity of SOD and GSH-Px reached the highest value at 12h after cold stress; while the activity of CAT and POD did at 24h. All the four types of the enzymes' activity decreased to the lowest point at 6h after cold stress.
|
PDF Full Text Request