Animal Tissue Culture:

The term tissue culture refers to the culture of all organs, tissue fragments and dispersed cells on a suitable nutrient medium. It may be divided into (1) cell culture (2) organ culture and basically on the basis of whether the tissue organisation is taken or not. In organ cultures all embryonic organs or small tissue fragments are cultured in vitro in such a manner that they achieve their tissue architecture. In compare, cell cultures are gained either by enzymatic or mechanical dispersed of tissues into particular cells or by spontaneous migration of cells from an explants; they are maintained as attached or as cell suspensions or  monolayers.

Newly isolated cell cultures are called primary cultures; they are typically heterogeneous and slow rising, but are more representative of the tissue of their origin both in properties and cell type. Once a first  culture is subcultured, this given rise to cell lines which can either die after many subcultures (such cell lines are known as finite cell lines) or can continue to grow indefinitely (these are called continuous cell lines. Generally normal tissues give rise to finite cell lines, whereas tumours give rise to continuous cell lines. But there are many examples of continuous cell lines which were imitative from normal tissues and are themselves non-tumorigenic, e.g.3T3 fibroblasts, MDCK dog kidney etc. The growth of continuous cell lines from primary cultures is supposed to involve a mutation which alters their properties as compared to those of finite lines.

 AugmentThe beginning of animal tissue culture may be traced to 1880 when Arnold showed that leucocytes may divide outside the body. Later in the year 1903, Jolly studied the behaviour of animal tissue explants immersed in serum. Lymph or ascites fluid. In the year 1907, Harrison cultured frog tadpole spinal cord in the lymph drop hanging from a cover slip into the cavity on microscopic slide; this is considered  as the turning point. Subsequently in the year 1913, Carrel developed a complicated method for maintaining cultures free from contamination, mainly  by bacteria. Afterwards, suitable culture media were developed and the techniques of cell culture were refined.