Sains Malaysiana 40(2)(2011): 163–171

 

An In Vitro Study to Evaluate the Genotoxicity of Value Added Hydroxyapatite as a Bone Replacement Material

(Kajian In Vitro untuk Menilai Genotoksisiti Hidroksiapatit Tambah Nilai sebagai Bahan Tulang Gantian)

 

Akram Hassan

School of Dental Sciences, Universiti Sains Malaysia

16150 Kubang Kerian, Kelantan, Malaysia

 

Dasan Swaminathan*

Department of Oral Pathology, Oral Medicine and Periodontology

Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia

 

Received: 3 March 2010 / Accepted: 9 June 2010

 

ABSTRACT

 

Hydroxyapatite (HA) used for bone replacement is one of the most active areas of ceramic biomaterials research currently. It has been used clinically for the last 20 years due to its excellent biocompatibility, osseoconduction and osseointegration. Many modifications have been done to develop a stronger, tougher and biocompatible ceramic biomaterial because pure HA is brittle. Researchers in Universiti Sains Malaysia had developed this value added HA that is stronger and less brittle compared to pure HA. The objective of this in vitro study was to evaluate the genotoxic characteristic of the value added HA based material by using Bacterial Reverse Mutation Assay (Ames test). The Bacterial Reverse Mutation Assay of HA was performed on Salmonella typhimurium strains TA98, TA100, TA1535, TA1537 and Escherichia coli strain WP2 uvrA using the preincubation method in the presence and absence of an exogenous metabolic activation system. All the bacterial tester strains treated with and without S9 Mix showed no increase of revertant colonies with increase in concentration of test substance for both the dose finding test and the main test. The number of revertant colonies was less than twice that of the solvent control for all the five bacterial strains and this was reproducible for both the dose finding test and the main test. The numbers of revertant colonies in the negative and positive controls were within the background data of our laboratory. In conclusion the results of the tests showed that the value added HA was considered to have no reverse mutagenic potential under the present test conditions.

 

Keywords: Ames test; genotoxicity; hydroxyapatite

 

ABSTRAK

 

Hidroksiapatit (HA) yang digunakan untuk tulang gantian merupakan salah satu daripada bidang penyelidikan biobahan seramik yang paling aktif masa kini. Ia diguna secara klinikal sejak 20 tahun dahulu disebabkan oleh sifatnya yang sangat baik daripada sudut bioserasi, oseokonduksi dan oseointegrasi. Banyak pengubahsuaian telah dilakukan untuk menghasilkan biobahan seramik yang lebih kuat, lebih keras dan bioserasi disebabkan HA yang asli adalah rapuh. Penyelidik Universiti Sains Malaysia telahpun menghasilkan HA tambah nilai ini yang lebih kuat dan kurang rapuh berbanding dengan HA asli. Tujuan kajian in vitro ini adalah untuk menilai sifat genotoksik bahan berdasarkan HA tambah nilai dengan menggunakan ‘Bacterial Reverse Mutation Assay’ (ujian Ames). ‘Bacterial Reverse Mutation Assay’ untuk HA ini telah dilakukan ke atas Salmonella typhimurium strain TA98, TA100, TA1535, TA1537 dan Escherichia coli strain WP2 uvrA dengan menggunakan cara prainkubasi dengan kehadiran dan ketidakhadiran sistem pengaktifan metabolik eksogenus. Kesemua strain bakteria yang diuji, yang dirawat dengan atau tanpa ‘S9 Mix’ menunjukkan tiada pertambahan koloni ‘revertant’ dengan penambahan kepekatan bahan yang diuji untuk ujian pencarian dos dan ujian utama. Jumlah bilangan koloni ‘revertant’ adalah berkurangan dua kali ganda dengan kawalan pelarut untuk kesemua lima strain bakteria dan ini adalah sama untuk kedua-dua ujian pencarian dos dan ujian utama. Jumlah bilangan koloni ‘revertant’ untuk kawalan negatif dan positif adalah dalam lingkungan data latar makmal. Kesimpulannya, keputusan daripada ujian-ujian menunjukkan HA tambah nilai ini telah dianggap tiada potensi mutagenik berbalik dalam keadaan yang diuji.

 

Kata kunci: Genotoksisiti; hidroksiapatit; ujian Ames

 

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Akram Hassan

 

*Corresponding author; email: dasans@um.edu.my

 

 

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