M Saxena, H Saxena, P Kaur, K Kaur
M Saxena, H Saxena, P Kaur, K Kaur. Effect of heavy metal pollution of water on response of fish lymphocytes to mitogenic stimulation. The Internet Journal of Veterinary Medicine. 2008 Volume 5 Number 2.
Two groups of six fish each were exposed to a combination of various compounds of eight heavy metals in water for two months. The concentration of the metals in the water was the same as found in the polluted water of Buddha Nallah, a drain of Ludhiana which flows through the heart of the city and joins the river Satluj. Levels of lymphocyte proliferation and lymphokine secretion by mitogen activated lymphocytes were analyzed. The difference in mean values of proteins in culture supernatants of activated lymphocytes between the Con-A stimulated normal and pollutant – exposed stimulated lymphocytes was not significant but the decrease in values in case of exposed fish was very significant (p=0.001)on PHA stimulation. No significant difference in cell proliferation on stimulation with the mitogens PHA or Con-A was found between normal and pollutant – exposed fish.
The aquatic habitat of fish is intimately associated with their body functions, including immune reactivity. These normal functions are susceptible to adverse changes in water quality. Occurrence of aquatic pollutants (such as heavy metals) has been correlated to alterations in the fish immune system and the incidence of infectious diseases. Even very low sub lethal doses of certain heavy metals can have profound effects upon the structure and / or functions of the immune system that could be almost as harmful as direct toxic doses. Ludhiana has a large number of industries for manufacturing bicycle parts, Nickel – Chrome plating, dyeing and woolen hosiery etc. The heavy metal Chromium is often found in the effluents of many industries especially Chrome plating and Chrome tanning industries which are a major source of pollution of surface and ground water.
Pollution of water with heavy metals may adversely affect the immune system of fish leading to decreased production, increased susceptibility to diseases and mortality. It is therefore, important to assess the effect of heavy metals on the immune system of fish.
The effect of heavy metals on cellular immunity of common carp fish (
Materials and methods
Response of lymphocytes to mitogen
The mean values of total proteins (mg/ml) in the culture supernatants of PHA stimulated lymphocytes were 0.061 ± 0.006 in case of normal fish (n=6) and 0.015 ± 0.05 in case of pollutant – exposed fish (n=6) (Table 2). The difference was very significant (p=0.001).
Proteins (mainly lymphokines like IL-2, IL-4 etc.) are secreted by lymphocytes after activation by mitogens. The effect of water pollution by heavy metals on lymphokine secretion by mitogen stimulated lymphocytes was studied by total protein estimation. The mean level of total proteins in culture supernatants of stimulated lymphocytes was significantly (p<0.05) lower in case of Con-A activation and very significantly (p=0.001) lower in case of PHA activation. These findings indicate the adverse effects of exposure to heavy metals on cellular immune responses in fish.
Hari Mohan Saxena, Flat no. 9, FF, Geetanjali Apartments, E-Block, Rishi Nagar, Ludhiana – 141001 India. E-mail: email@example.com